US ISSN: 0025-4231
BULLETIN ©F THE
TIRacylanb
f>erpetological
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DEPARTMENT OF HERPETOLOGY
THE NATURAL HISTORY SOCIETY OF MARYLAND, INC.
MDHS . A Founder Member of the Eastern
Seaboard Herpetological League
JANUARY-DECEMBER 2011 VOLUME 47 NUMBER SI-4
MAR 0 l Aw.i
BULLETIN OF THE MARYLAND HERPETOLOGICAL SOCIETY
Volume 47 Numbers 1-4 January-December 2011
CONTENTS
Geographic Variation in Northern Green Frog Larvae, Lithobates Clamitans Melanotus, in
Northwestern New Jersey
John K. Korky and John A. Smallwood . . . 1
Seasonal Activity, Reproductive Cycles, and Growth of the Bronze Frog (. Lithobates clamitans
clamitans ) at the Western Edge of its Geographic Range
Walter E. Meshaka, Jr., Samuel D. Marshall and David Heinicke . 11
Seasonal Activity, Reproductive Cycles, and Growth of the Northern Leopard Frog, Lithobates
pipiens (Schreber, 1782), From Pennsylvania
Walter E. Meshaka, Jr., Pablo R. Delis, Sarah A. Mortzfeldt . . ...23
Clutch characteristics of the Southern Leopard Frog, Lithobates sphenocephalus (Cope, 1886), in
Natchitoches, Louisiana
Walter E. Meshaka, Jr. and Samuel D. Marshall... . 36
The Effects of Temperature and Salinity on Wood Frog {Lithobates sylvaticus ) Tadpole Growth
and Survival
Jennifer H. Clemmer, Eliza Z. Miller, Laura Wolgamott, Geoffrey R. Smith
and Jessica E. Rettig . . . . . 38
Body temperatures of Hyla arenicolor from Sierra de Tepozotlan, Estado de Mexico, Mexico
Felipe Correa-Sanchez, Geoffrey R. Smith, Guillermo A. Woolrich-Pina, and
Julio A. Lemos-Espinal . . . ..42
Clutch characteristics of the Pickerel Frog, Lithobates palustris (LeConte, 1825), in
Natchitoches, Louisiana
Walter E. Meshaka, Jr. and Samuel D. Marshall . . . . . . . .45
Distribution of Tadpoles {Hyla arenicolor ) in the Ponds Associated To Rio Salado, Puebla,
Mexico
Guillermo A. Woolrich-Pina. Julio A. Lemos-Espinal- Geoffrey R. Smith-
Raymundo Montoy a- Ay ala and Luis Oliver-Lopez. . 47
Mississippi Map Turtle, Graptemys pseudogeographica kohnii. Documented in Frederick
County Maryland
Wayne G Hildebrand . . . . . . . . . .....51
Reproduction in Clark’s Spiny Lizard, Sceloporus clarkii (Squamata: Phrynosomatidae) From
Sinaloa, Mexico
Stephen R. Goldberg . . . . . . . .53
Harassment/Predation of Maryland Snakes by Bird Species
Herbert S. Hams, Jr. . . . . . . . 58
BULLETIN OF THE
mbt)6
Volume 47 Numbers 1-4 January-December 2011
The Maryland Herpetological Society
Department of Herpetology, Natural History Society of Maryland, Inc.
President Tim Hoen
Executive Editor Herbert S. Harris, Jr.
Steering Committee
Jerry D. Hardy, Jr. Herbert S. Harris, Jr.
Tim Hoen
Library of Congress Catalog Card Number: 76-93458
Membership Rates
Membership in the Maryland Herpetological Society is $25.00 per year
and includes the Bulletin of the Maryland Herpetological Society. For¬
eign is $35.00 per year. Make all checks payable to the Natural History
Society of Maryland, Inc.
Meetings
Meetings are held monthly and will be announced in the “Maryland
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.
Volume 47 Numbers 1-4
January-December 2011
Geographic Variation in Northern Green Frog Larvae,
Lithobates Clamitans Melanotus, in Northwestern
New Jersey
John K. Korky* & John A. Smallwood
Abstract
A total of 124 larvae of the northern green frog, Lithobates clamitans melanotus (Rafin-
esque 1 820), were collected at five localities in three adjacent counties of northwestern New Jersey
from 200 1 to 2007 . Data were recorded for 1 9 varying character states that included 1 8 morphometric
features (body dimensions and characteristics of the oral disc) and developmental stage. Develop¬
mental stage differed significantly among the localities. Tables of univariate descriptive statistics
are provided for the 18 morphological features from all sites. Regression analyses of body length
over developmental stage and tail length over developmental stage determined that larvae from one
locality (Allamuchy State Park) differed markedly from the larvae from the other four localities.
Four localities expressed the larval tooth row formula (LTRF) 2(2)/ 3, while Chubb Park was 2(2)/
3(1). Phenotypic plasticity likely accounts for some of the variation of all characters.
Introduction
Northern green frogs are commonly found throughout New Jersey in a variety of perma¬
nent, freshwater habitats, and are named Rana clamitans melanota by Schwartz and Golden (2002).
Using mtDNA data, Hillis and Wilcox (2005) retained the use of the genus Rana , placing them in
their Aquarana group. Based on molecular data. Frost et al . (2006) placed the species clamitans in the
genus Lithobates , requiring the use of this genus with the subspecific name changing to melanotus ,
but retaining the common name as green frog. In contrast, Austin and Zamudio (2008) presented
mtDNA data that suggested the recognition of the subspecies was not supported. However, their
finding was rejected by an eminent anuran systematist group (Center for North American Herpe¬
tology, http://cnah.org/detail .asp?id=l 163). As a result, Collins and Taggart (2009) designated the
green frog as Lithobates clamitans melanotus (Rafinesque 1 820), as does Frost (201 1 ).
Since natural selection operates on anuran larvae (tadpoles) as well as adults, studies
focused on the larvae are warranted. This study entails the examination of 124 field-collected larvae
from five sites in three adjacent counties of northwestern New Jersey (Morris, Warren, Sussex),
known as The Highlands. The purpose of the study was to: ( 1 ) document the occurrence of the taxon
with habitat notes, (2) document geographic variation of 1 8 morphometric characters from selected
sites using descriptive statistics, and (3) analyze patterns of variation among populations.
Methods
Field collections: Field collections of 124 tadpoles were made by one of us (JKK) at
five different sites between 2001 and 2007. Three of the sites were collected twice in two different
years. The following are the collection localities and dates of collection. ( 1 ) Chubb Park, State Route
24, Chester, Morris County (40° 46' 57.5” N, 74° 42' 36.1' W; elevation 253 m AMSL), a 0.71-ha
rectangular, man-made pond of an approximately 1-m uniform depth used for winter ice skating in
34-ha park of grassland and woodlands. A total of 21 specimens were collected on 3 July 2001 and
26 June 2002.(2) Intersection of Colby Farm Road and Knolhvood Terrace, Chester, Morris County
Key words: Lithobates clamitans melanotus , green frog tadpoles, morphometric variables, oral
disc, phenotypic plasticity. New Jersey.
Bulletin of the Maryland Herpetological Society
page 1
Volume 47 Numbers 1-4 January-December 2011
(40° 46’ 48.5” N, 74° 40’ 58.9’ W; elevation 249 m), a 0.05-ha artificial retention basin in a housing
subdivision, with marginal aquatic vegetation surrounding a >1 .25-m deep circular basin. A total
of 13 specimens were collected on 3 July 2001 and 26 June 2002. (3) Allamuchy State Park, Deer
Park Road, Hackettstown, Warren County (40° 53’ 15.0” N, 74° 49' 23.5’ W; elevation 273 m), a
0.05-ha natural pond of approximately 1 m depth near a house on the access road to interior of ap¬
proximately 3500 ha of diverse habitat. Twenty-seven specimens were collected on 21 June 2007.
(4) Schooley’s Mountain, West Springtown Road, Long Valley, Morris County (40° 47’ 6.0'’ N, 74°
48’ 29.4’ W; elevation 329 m), a 1 .50-ha spring fed pond, approximately 3.5 m deep at center on
residential property. Thirty-three specimens were collected on 1 1 September 2006. (5) New Jersey
School of Conservation, Montclair State University, Branchville, Sussex County (41° 13' 1 .7” N,
74° 44’ 50.2’ W; elevation 268 m), a 0.2-ha flooded beaver pond area with slowly moving water
and fallen trees. A total of 30 specimens were collected on 8 July 2002 and 14 July 2003.
TABLE 1. Descriptive statistics of selected character states for Lithobcites c lam i tans melanotus
larvae from Chubb Park, Morris County, New Jersey, 2001-2002. All measurements are in mm.
Range is minimum value-maximum value. Developmental stages for specimens included stage 26
(n = 3), stage 28 ( n = 2), stage 30 ( n = 2), stage 36 (n = 3), stage 37 (n = 1), stage 38 ( n = 2), stage
39 (/? = 2), stage 40 (n = 4), and stage 41 (n = 2).
Variable
n
Mean
Median
SD
Range
Body length
21
29.3
33.0
9.1
13.0-39.0
Tail length
21
42.7
48.0
13.9
18.0-59.0
Total length
21
72.0
80.0
23.0
31.0-97.0
Tail height
21
14.6
16.0
3.7
7.0-19.5
Tail muscle height
21
7.5
8.1
2.3
3.5-10.0
Dorsal fin height
21
4.7
4.8
1.2
2. 5-7.0
Ventral fin height
21
3.5
3.5
0.9
2. 0-5 .2
Interocular distance 21
10.0
11.0
3.8
3.0-14.5
Internareal distance 21
3.4
3.5
0.9
1 .5-4.6
A-l length
21
3.6
3.7
1.5
0. 7-6.0
Left A-2 length
12
0.9
0.9
0.4
0. 3-1.4
Right A-2 length
14
1.0
1.0
0.4
0.5- 1.7
A-2 gap
12
2.5
2.5
0.6
1.5-3 .6
A-2 gap ratio
12
0.5
0.5
0.2
0.2-0.9
P-1 length
21
3.5
3.6
1.2
1. 1-4.8
P-1 gap
6
0.2
0.2
0.1
0. 1-0.3
P-2 length
21
3.4
3.5
1.1
0.9-4 .6
P-3 length
14
2.4
2.4
1.1
0.2-3 .7
page 2
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Tadpoles were obtained by hand net and preserved in 10% formalin, and are in the cus¬
tody of the senior author. Larvae were identified by keys (Altig 1970, Altig and Johnston 1986),
the online guide of Altig et al. (http://www.pwrc.usgs.gov/ tadpole/), and the presence of adults in
some cases. Larvae were staged according to Gosner (1960).
Morphological measurements: Measurements of body features were made with Cenco
calipers, whereas those of the oral disc were made with dissecting microscope and ocular micrometer
calibrated to the nearest 0.1 mm. Descriptive features follow Altig (1970) and McDiarmid and Altig
(1999), and included body length, tail length, total length, tail height, tail muscle height, dorsal
fin height, ventral fin height, interocular distance, internareal distance. A- 1 length, left A-2 length,
right A-2 length. A-2 gap, A-2 gap ratio, P-1 length, P-1 gap, P-2 length, and P-3 length. Thus,
TABLE 2. Descriptive statistics of selected character states for Lithobates clamitans melanotus
larvae from Colby Farm Road, Morris County, New Jersey, 2001-2002. All measurements are in
mm. Range is minimum value-maximum value. Developmental stages for specimens included stage
26 ( n = 1), stage 27 ( n = 1), stage 28 (n = 1), stage 29 (n = 1), stage 36 (/? = 1), stage 37 ( n - 2),
stage 38 (n = 1), stage 41 (n = 1), stage 42 (n = 1), stage 43 (/? =1), and stage 44 ( n - 2).
Variable
n
Mean
Median
SD
Range
Body length
13
24.2
26.0
6.4
13.0-36.0
Tail length
13
33.8
36.0
10.2
20.0-47.0
Total length
13
57.5
60.0
14.3
33.0-74.0
Tail height
13
11.9
11.0
4.6
5.0-19.5
Tail muscle height
13
5.8
5.1
1.9
2.5-8.8
Dorsal fin height
13
4.0
3.5
1.6
1 .5-6.5
Ventral fin height
13
2.8
3.0
1.4
1.0-5 .4
Interocular distance
13
6.8
6.8
1.8
3. 5-9 .4
Internareal distance
13
3.1
3.4
0.6
1.8-3 .7
A-l length
10
2.8
3.1
0.9
1.5-3 .7
Left A-2 length
3
0.5
0.6
0.2
0.3-0.6
Right A-2 length
4
0.6
0.5
0.4
0.2- 1.2
A-2 gap
3
2.0
1.9
0.2
1. 8-2.2
A-2 gap ratio
3
0.4
0.3
0.2
0.2- 0.6
P-1 length
10
2.6
2.7
0.7
1.4-3 .4
P-2 length
10
2.3
2.6
0.9
1. 1-3.5
P-3 length
7
1.6
1.6
0.4
1. 0-2.0
Bulletin of the Maryland Herpetological Society page 3
Volume 47 Numbers 1-4
January-December 2011
16 direct measurements, 2 derived variables (total length and A-2 gap ratio), and developmental
stage were recorded for each tadpole from the five selected sites. Some specimens had missing or
damaged body or oral disc features.
Data analyses: We calculated descriptive statistics of central tendency and variability for
each of the 1 8 morphometric variables. However, developmental stage differed significantly among
the five locations (Kruskal-Wallis Rank Sums Test, chi-square approximation = 42.6, df = 4, P <
0.0001). Thus, we did not compare these variables directly among the five locations. Instead, fol¬
lowing Strauss and A1 tig (1992) we first converted measurements to natural logarithms, and then for
each location we used regression models to describe the change in selected morphometric variables
in relation to developmental stage. We then compared those regressions among locations. Tests of
significance were performed using JMP version 8.0.2, and regression models were calculated with
TableCurve 2D version 5.01 .
TABLE 3. Descriptive statistics of selected character states for Lithobates clamitans melanotus
larvae from Allamuchy State Park, Warren County, New Jersey, 2007. All measurements are in mm.
Range is minimum value-maximum value. Developmental stages for specimens included stage 31
(n = 1 ), stage 32 (n = 5), stage 33 (n = 9), stage 34 ( n = 5), stage 35 (n = 5), and stage 36 (n = 2).
Variable
n
Mean
Median
SD
Range
Body length
27
9.6
10.0
0.9
7.5-10.5
Tail length
27
10.6
11.0
1.6
8.0-13.5
Total length
27
20.2
21.0
2.2
15.5-24.0
Tail height
27
3.7
3.5
0.5
2.8-4 .5
Tail muscle height
27
1.8
2.0
0.3
1 .2-2.2
Dorsal fin height
27
1.3
1.2
0.3
0. 5-2.0
Ventral fin height
27
1.4
1.4
0.3
1. 0-2.0
Interocular distance
27
2.4
2.4
0.2
2. 0-2. 8
Internareal distance
27
1.5
1.5
0.2
1.0- 1.8
A-l length
27
1.6
1.6
0.2
0.9-2 .0
Left A-2 length
27
0.5
0.5
0.2
0.2-0.8
Right A-2 length
27
0.6
0.6
0.2
0.3-0.8
A-2 gap
27
0.4
0.3
0.1
0. 1-0.7
A-2 gap ratio
26
1.7
1.7
0.7
0.6-3 .5
P-1 length
27
1.4
1.5
0.2
1. 1-1.7
P-2 length
27
1.3
1.3
0.2
1. 1-1.7
P-3 length
26
1.1
1.0
0.2
0.8- 1.5
page 4
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
Results
January-December 2011
Measures of central tendency and variability in the 18 morphometric characters of the
samples collected from Chubb Park are presented in Table 1 ; 6 of 21 larvae had the unique LTRF of
2(2)/3(l), indicating a P-1 median gap. P-1 gap was not expressed on any tadpoles from the other
four localities; these larvae showed a LTRF of 2(2)/3. Measures of central tendency and variability
in the remaining 17 morphometric characters of specimens from the four other collection localities
are presented in Tables 2 through 5.
The following regression model most consistently provided the best fit for the relationship
of body length with developmental stage: length = a + b/stageL The samples from Allamuchy State
Park differed markedly from the other four locations (Figure 1 ). The same regression model also most
TABLE 4. Descriptive statistics of selected character states for Lithobates clamitans melanotus
larvae from Schooley ’s Mountain, Morris County, New Jersey, 2006. All measurements are in mm.
Range is minimum value-maximum value. Developmental stages for specimens included stage 26
(n = 1), stage 27 (n = 2), stage 28 (n = 2), stage 29 (n = 4), stage 30 (n = 4), stage 31 (/? = 15), stage
32 (n = 1), stage 33 (n = 2), and stage 36 (n = 2).
Variable
n
Mean
Median
SD
Range
Body length
33
19.0
19.0
2.4
14.0-24.0
Tail length
33
26.6
27.0
4.1
18.0-35.0
Total length
33
45.6
47.0
6.3
32.0-59.0
Tail height
33
9.7
10.0
1.3
7.0-12.2
Tail muscle height
33
4.1
4.2
0.5
3. 2-5.0
Dorsal fin height
33
3.4
3.3
0.5
2.5-4 .5
Ventral fin height
33
2.8
2.8
0.4
2.0-3 .5
Interocular distance
33
5.3
5.5
0.9
3. 8-7 .2
Internareal distance
33
3.1
3.2
0.4
2.2-3 .9
A-l length
33
2.3
2.4
0.3
1. 6-3.1
Left A-2 length
31
0.3
0.3
0.2
0.1 -0.6
Right A-2 length
30
0.4
0.4
0.2
o
o
Li
A-2 gap
29
1.2
1.2
0.3
0.9-2. 1
A-2 gap ratio
29
0.4
0.4
0.2
0.1 -0.7
P-1 length
33
2.1
2.1
0.4
1. 1-3.0
P-2 length
33
2.1
2.1
0.4
1.4-3 .0
P-3 length
32
1.2
1.2
0.4
0.6-2. 1
Bulletin of the Maryland Herpetological Society
page 5
Volume 47 Numbers 1-4
January-December 2011
consistently provided the best fit for the relationship of tail length with developmental stage, and
again the samples from Allamuchy State Park were markedly different from the samples obtained at
the other four locations (Figure 2). Mean total length of the Allamuchy State Park larvae (20.2 mm)
was less than half the mean lengths from the four other localities (45.6-72.0 mm; Tables 1-5).
Discussion
Altig and Johnston (1989, Table 1 ) showed the LTRF 2/3 to be most common (51%) and
highly conserved of 320 anuran species studied of a total of 627. All our 124 larvae were slight
derivatives of this prime formula, and are consistent with the species being a lentic-benthic pond
form with reduced oral apparatus complexity.
TABLE 5. Descriptive statistics of selected character states for Lithobates clamitans melanotus
larvae from the School of Conservation, Sussex County, New Jersey, 2002-2003. All measure¬
ments are in mm. Range is minimum value-maximum value. Developmental stages for specimens
included stage 28 (n = 2), stage 29 (n = 1 ), stage 32 (n = 1), stage 35 (n= 1), stage 36 (n = 4), stage
37 ( n = 2), stage 38 (n = 1), stage 39 ( n = 6), stage 40 ( n = 4), stage 41 ( n = 7), stage 42 (n = 1),
and stage 46 (n - 1).
Variable
n
Mean
Median
SD
Range
Body length
30
26.9
27.5
3.3
17.0-33.0
Tail length
30
41.7
43.0
8.9
21.0-59.0
Total length
30
68.6
70.0
11.6
39.0-88.0
Tail height
30
13.9
14.5
2.4
7.5-19.0
Tail muscle height
30
7.6
7.7
1.3
4.0-9.5
Dorsal fin height
30
4.2
4.5
0.7
2.5-5 .5
Ventral fin height
30
2.8
2.9
0.8
1 .0-4.5
Interocular distance
28
8.5
oo
bo
0.7
6.5-9.6
Internareal distance
30
3.8
4.0
0.4
3. 0-4 .4
A-l length
27
2.5
2.8
0.7
0.5-3 .3
Left A-2 length
10
0.3
0.4
0.1
0.1 -0.6
Right A-2 length
8
0.5
0.5
0.3
0.2-1. 1
A-2 gap
4
2.1
2.0
0.5
1. 8-2.8
A-2 gap ratio
4
0.3
0.3
0.1
0.2-0.3
P-1 length
27
2.7
2.7
0.5
1. 3-3.8
P-2 length
27
2.2
2.3
0.5
1.0-2. 8
P-3 length
21
1.1
1.1
0.5
0.2-2.0
page 6 Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
While developmental stage was determined to be statistically different between localities,
variability in the oral apparatus cannot be explained solely by stage difference as the assumption
that stage and oral disc development are tightly correlated is not warranted McDiarmid and Altig
(1999, p.45).
It is notable the two localities in Chester, Chubb Park and Colby Farm Road, are about
2.5 km apart. Yet, the former had 6 of 21 specimens with a P-1 gap. while none of the 13 at the
latter had any with that gap. The specific reason for this is unclear.
Variation in the data may be attributed to some combination/permutation of the following
factors: ontogenetic variation, nonadaptive variation, and phenotypic plasticity. The percentage each
factor may contribute singularly or synergistically has not been determined in studies, but phenotypic
plasticity has been investigated the most, particularly with tadpoles as subjects.
Phenotypic plasticity is an adaptive phenomenon wherein one genotype can produce mul¬
tiple phenotypes as a function of abiotic and biotic factors. This plasticity can result in behavioral,
physiological, morphological, and life history alterations (Miner et al. 2005).
The nature of the habitat alone, field-collected versus laboratory-reared, was shown by
Hillis (1982) to induce morphological variation in conspecifics. Not surprisingly, food availability
affected both age and size at metamorphosis (Hensley 1 993). Impending pond desiccation increased
FIGURE 1. The relationship of body length and developmental stage for Lithobates clamitans
melanotus larvae collected at five locations in northwestern New Jersey, 2001-2007. Regression
model for Chubb Park: ln(length) = 4.1 - 949.3/stage2, r2 = 0.73; for Colby Farm Road: ln(length)
= 3.7 -668.7/stage2, r2 = 0.71 ; for Allamuchy State Park: ln(length) = 3.1 - 951 .9/stage2, r2 = 0.46;
for Schooley’s Mountain: In(length) = 3.8 -789.3/stage2, r2 = 0.82; and for School of Conservation:
ln(length) = 3.7 - 61 1 .9/stage2, r2 = 0.74.
Bulletin of the Maryland Herpetological Society
page 7
Volume 47 Numbers 1-4
January-December 2011
speed of development with earlier metamorphosis and smaller size (Laurila and Kujasalo 1999),
an obvious survival facilitator. Predator presence is another factor. Miner et al. (2005), Kraft et
al. (2006), and Van Buskirk and Relyea (2008) all demonstrated such presence resulted in smaller
bodies with larger tail fins, presumably aiding predator escape by better swimming and being able
to survive a tail bite compared to a fatal body bite.
Predator presence also may increase the toxic effects of pesticide use (Relyea 2003).
Carbaryl is a water soluble pesticide used globally. He tested green frogs as one of six amphibian
species exposed to the pesticide and simultaneous predator stress. The lethality of exposure increased
many times with predator presence.
Sometimes the changing subtle interaction of factors may lead to study discordance, as
in those of green frog tadpoles. Schalk et al. (2002), using a leech as a high risk larval predator,
showed delayed metamorphosis and a larger size at metamorphosis. Ireland et al. (2007), using a
leech as a green frog egg predator, determined metamorphosis occurred at an earlier stage with a
smaller size at hatching. Thus, the same predator at a different life history stage of the same species
produced markedly different plasticity outcomes.
Suffice to say, further investigations of the abiotic and biotic factor interplay influencing
larval morphology are warranted, and will be challenging evolutionary biology, but will better il¬
luminate the mechanisms of Natural Selection.
FIGURE 2. The relationship of tail length and developmental stage for Lithobcites clamitans mela-
notus larvae collected at five locations in northwestern New Jersey, 2001-2007. Regression model
for Chubb Park: ln(length) = 4.6 - 983.7/stage2, r2 = 0.73; for Colby Farm Road: ln(length) = 4.3
- 843.1/stage2, r2 = 0.80; for Allamuchy State Park: ln(length) = 3.8 - 1630.9/stage2, r2 = 0.57; for
Schooley’s Mountain: ln(length) = 4.3 - 926.8/stage2, r2 = 0.77; and for School of Conservation:
ln(length) = 4.5 - 1052.0/stage2, r2 = 0.69.
h= 35
0
Z
111
E
E
X
45
55
B
A
15
A . Chubb Park
B — Colby Farm Road
C — Allamuchy State Park
D - - Schooley’s Mountain
E — School of Conservation
5
25
30
35
STAGE
40
45
page 8
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Acknowledgments
Release time for JKK and JAS was provided by the Faculty Scholarship Program , Mont¬
clair State University. We also thank Independent Study student, Mr. Brian Platt, for his contribution
of morphometric measurements.
Literature Cited
Altig, R.
1970. A key to the tadpoles of the United States and Canada. Herpetologica 26:
180-207.
Altig, R., & Johnston, G. F.
1986. Major characteristics of free-living anuran tadpoles. Smithsonian Herpeto-
logical Information Service 67: 1-75.
Altig, R. and G. F. Johnston, G. F.
1989. Guilds of anuran larvae: relationships among developmental modes, mor¬
phologies, and habitats. Herpetological Monographs 3: 81-109.
Austin, J. D., & Zamudio, K. R.
2008. Incongruence in the pattern and timing of intra-specific diversification in
Bronze Frogs and Bullfrogs (Ranidae). Molecular Phylogenetics and Evolu¬
tion 48: 1041-1053.
Collins, J. T., & Taggart, T. W.
2009. Standard common and current scientific names for North American amphib¬
ians, turtles, reptiles, and cocodilians. Sixth Edition. Publication of The Center
for North American Herpetology, Lawrence, iv + 44pp.
Frost, D. R.
2011. Amphibian species of the World: an online reference. Version 5.5. (3 1 January,
2011). http://research.amnh.org/vz/herpetology/amphibia/American Museum
of Natural History, New York, USA.
Frost, D. R., Grant, T., Faivovich, J., Bain, R. H.. Haas, A., Haddad, C. F. B., de Sa, R. O., Chan-
ning. A., Wilkinson. M., Donnellan, S. C., Raxworthy, C. J.. Campbell, J.
A., Blotto, B. L., Moler, P, Drewes, R. C., Nussbaum, R. A., Lynch, J. D.,
Green, D. M„ & Wheeler, W. C.
2006. The amphibian tree of life. Bulletin of the American Museum of Natural
History 297: 1-370.
Gosner, K. L.
1960. A simplified table for staging anuran embryos with notes on identification.
Herpetologica 16: 183-190.
Hensley, F. R.
1 993 . Ontogenetic loss of phenotypic plasticity of age at metamorphosis in tadpoles.
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Hillis, D. M.
1982. Morphological differentiation and adaptation of the larvae of Rana berlan-
dieri and Rana sphenocephala ( Rana pipiens complex) in sympatry. Copeia
_ 1982(1): 168-174. _
Bulletin of the Maryland Herpetologica! Society
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Hillis, D.M..& Wilcox, T.P.
2005. Phylogeny of the New World true frogs ( Rana ). Molecular Phylogenetics
and Evolution 34: 299-314.
Ireland. D. H.. Wirsing, A. J.. & Murray, D. L.
2007. Phenotypical ly plastic responses of green frog embryos to conflicting preda¬
tion risk. Oecologia 152(1): 162-168.
Kraft, P. G., Franklin, C. E„ & and Blows., M. W.
2006. Predator-induced phenotypic plasticity in tadpoles: extension or innovation?
Journal of Evolutionary Biology 19(2): 450-458.
Laurila, A.. & Kujasalo, J.
1999. Habitat duration, predation risk and phenotypic plasticity in common frog
(Rana temporaria ) tadpoles. Journal of Animal Ecology 68(6): 1123-1132.
McDiarmid. R. W., & Altig, R.
1 999. Tadpoles: the biology of anuran larvae. University of Chicago Press, Chicago,
444 pp.
Miner. B. G., Sultan, S. E., Morgan, S. G., Padilla, D. K., & Relyea, R. A.
2005. Ecological consequences of phenotypic plasticity. Trends in Ecology &
Evolution 20( 1 2): 685-692.
Relyea, R. A.
2003. Predator cues and pesticides: a double dose of danger for amphibians. Eco¬
logical Applications 13: 1515-1521.
Schalk, G., Forbes, M. R.. & Weatherhead, P. J.
2002. Developmental plasticity and growth rates of green frog ( Rana clamitans )
embryos and tadpoles in relation to a leech (Macrobdella decora) predator.
Copeia 2002: 445-449.
Schwartz, V., & Golden, D. M.
2002. Field guide to reptiles and amphibians of New Jersey. New Jersey Division
of Fish and Wildlife, Trenton. 89 pp.
Strauss, R. E., & Altig, R.
1992. Ontogenetic body form changes in three ecological morphotypes of anuran
tadpoles. Growth, Development, & Aging 56:3-16.
Van Buskirk, J., & Relyea, R. A.
1998 Selection for phenotypic plasticity in Rana sylvatic tadpoles. Biological
Journal of the Linnean Society 65(3): 301 1-328.
Department of Biology and Molecular Biology, Montclair State University, Montclair,
New Jersey 07043, *korkyj@ mail. montclair.edu
Received: 2 1 October 20 1 0
Accepted: 1 November 2011
page 10
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Seasonal Activity, Reproductive Cycles, and Growth
of the Bronze Frog (Lithobates clamitans ciamitans) at the
Western Edge of its Geographic Range
Abstract
Seasonal activity, reproduction, and growth of the Bronze Frog ( Lithobates clamitans
clamitans ) from Texas were examined using 278 museum specimens and calling data. Post-meta-
morphic individuals were active throughout the year, and metamorphoslings were captured over an
extended season. Males called, and females were gravid, over an extended time in eastern Texas.
Larval transformation occurred at small body sizes and sexual maturity was reached quickly and
at small body sizes, with males being smaller in mean body size than females. Findings relating to
activity, reproduction, and growth in this study were in general agreement with those from Louisiana.
Our findings suggest that factors apart from those studied here were responsible for the western
limit of its geographic range.
Introduction
The Bronze Frog, Lithobates clamitans clamitans (Latreille 1 80 1 ), is one of two recognized
subspecies of the eastern North American Bronze Frog, L. clamitans (Latreille 1801). Occurring in the
southeastern United States, it intergrades with the Green Frog, L. clamitans melanotus (Rafinesque
1820) along the fall line in Georgia and Alabama, which in turn replaces the Bronze Frog north to
southeastern Canada (Conant and Collins 1998; Pauley and Lannoo 2005). Less attention has been
paid to the Bronze Frog in the literature than its nearest relative despite the ubiquity of this species
in generally lentic aquatic systems in the southeastern United States. Examination of this species in
Louisiana (Meshaka et al. 2009a,b) corroborated findings of small body size of metamorphoslings
(Wright and Wright 1949) and adults (Wright and Wright 1949; Mecham 1954) of the Bronze Frog
and found longer seasons of activity and reproduction and faster post-metamorphic growth to sexual
maturity than in northern populations of the Green Frog (Meshaka et al. 2009a). The goal of this
study was to compare these same parameters from the western edge of the Bronze Frog’s geographic
range and the southwestern edge of the Green Frog’s geographic range to test the endpoint in the
geographic variation of these life history traits
Materials and Methods
Two hundred and seventy-eight specimens of Bronze Frogs ( Lithobates clamitans clami¬
tans) collected during 1931-2000 from eastern Texas (Figure 1) were examined from the holdings
of the California Academy of Sciences, Carnegie Museum of Natural Flistory, Field Museum of
Natural History, Los Angeles County Museum of Natural History, Illinois Natural History Survey,
Northwestern State University, Texas Cooperative Wildlife Collection, Texas Memorial Museum,
Tulane University, University of Arizona, University of Kansas Biodiversity Institute, University
of Michigan, and the University of Texas-El Paso (Appendix 1). Body lengths of all size-classes
and of tadpoles were measured in mm snout-vent length (mm SVL).
Sexual maturity was determined in males using a slightly modified version of the technique
by Martof (1956), whereby the ratio of tympanum diameter: body size corresponded to enlarged
Keywords. Bronze Frog, ecology, frogs, life history,
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
testis, which signified sexual maturity. Martof ( i 956) noted that the tympana generally were “nearly
or quite round.” For most frogs Martof (1956) measured the antero-posterior diameter of the left
tympanum. If irregular in shape, the right tympanum was measured, and if both were misshapen,
Martof (1956) took the average of the antero-posterior and dorso-ventral measurements. Irregu¬
larly shaped tympana from our sample were greater in length than in height. For consistency, the
dorso-ventral diameter of the left tympanum was measured, and the right tympanum was measured
only if the left one appeared to have been damaged in some way. As per Martof (1956), sex index
= body length/ tympanum diameter. The sex index was generally below 10 for sexually mature
males (Martof 1956).
The secondary sexual characteristic of enlarged thumbs was not easily ascertained. The
yellow throat of mature males, which easily fades to varying degrees in preservative, was not ap¬
parent. The length and width of the left testis as a percent of the body size was used to measure
seasonal differences in testis dimensions.
Sexually mature females were associated with one of four ovarian stages. In the first
ovarian stage oviducts were thin and just beginning to coil, and the ovaries are somewhat opaque.
In the second ovarian stage, the oviducts were larger and more coiled, and the ovaries contained
some pigmented oocytes. In the third ovarian stage, oviducts were thick and heavily coiled, and the
ovaries were in various stages of clutch development. In the fourth ovarian stage, oviducts were
Figure 1. Texas counties from which 278 museum specimens of Bronze Frogs ( Lithobates clomitans
clamitans ) were examined in this study.
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
thick and heavily coiled, and the ovaries were full of polarized ova with few non-polarized ova,
signifying a fully ripened clutch and gravid female (Meshaka 2001). Fat body development was
scored as absent, intermediate in volume in the body cavity, to extensive development that reached
upwards in the body cavity. The latter amount was used as an estimation monthly incidence of
extensive fat relative to all females examined in each month.
Tadpoles were scored as per Gosner (1960). For practical purposes, tadpoles were in
categories of having poorly-developed hind legs (less than Gosner stage 37) or well-developed
hind legs (Gosner stage of at least 37). Metamorphoslings were distinguished from tadpoles by
the presence of forelimbs (Gosner stage 42) and distinguished from juveniles by the presence of a
tail . Statistical analysis was conducted with the use of Excel . Means were followed by + 2 standard
deviations, and significance was recognized at P < 0.05.
The following sources of calling records were shared in response to Research Request
#1 from the Center of north American Herpetology. Calling was monitored at Ratcliff Lake in the
Davy Crockett National Forest (DCNF) in Houston County of eastern Texas during 1961-1982
(Edward Greding, unpbl. data). Also at DCNF, calling was monitored at four ponds during 2000-2004
(Daniel Saenz unpubl . data). Calling was monitored at four sites at Brazos Bend State Park (BBSP),
Fort Bend County, of eastern Texas during January 1999-November 2004 by DH. Exceptionally,
July and October 2004 were not monitored. Those data are presented as number of sites with calls.
Regional calling data from the Texas Amphibian Watch and FrogWatch USA volunteers and the
U.S. Forest Service, Southern Forest Experimental Station during 1999-2003 was provided by Lee
Ann Johnson Linam of the Texas Parks and Wildlife Department. Regions corresponded to North
American Amphibian Monitoring Program sampling regions.
Results
Seasonal activty.— Bronze Frogs from southern Texas were collected in every month
of the year (Figure 2). Most individuals were found during April-June, especially males and this
seasonal peak was followed by a November peak comprised mostly of juveniles (Figure 2).
Seasonal changes in testis size.— Measured as a percentage of male body size, testis
length and width were largest in Spring (Figure 3).
Calling — Bronze Frogs were heard calling during 22 April-10 August at Ratcliff Lake
in DCNF. At four ponds also at DCNF, calling began in March {n = 8) (earliest = 17 March 2004)
or April (n = 7) and ended in August ( n = 3) or September (n = 1 2) (latest = 1 0 September 2000) . At
BBSP calling was heard during March-September (Figure 4). Regional monitoring revealed calling
during March-October in coastal Texas and during March-September in north/east Texas.
Air (mean = 24.4 ± 2.6 0C; range = 18-29; n = 25) and water (mean = 24.5 ± 2.7 0C;
range = 18-28; n = 22) temperatures associated with calling at BBSP were generally warm, most
having been within 24-27 0C range (Figure 5). Relative humidity associated with calling was high,
generally 80-90% RH (Figure 6). Calling also occurred in primarily still conditions: < 1 rnph (n =
21), 1-3 mph (n = 2), 4-7 mph (n =1).
Ovarian cycle.— Gravid (stage 4) females were detected during April-September
(Figure 7). Yolking-nearly gravid (stage 3) females were captured during March-August (Figure
7). The high frequency of stage 3 females in March, and the highest frequencies of stage 1 and 2
females during October-December were suggestive of a gravid condition having occurred during
March-September (Figure 7).
Female fat cycle and the presence of food.— The extent to which fat bodies were well-
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4 January-December 2011
Figure 2. Seasonal incidence of captures of 272 Bronze Frogs (Lithobates clamitans clamitans)
from eastern Texas.
Figure 3. Monthly distribution of testis size as a percentage of body size of 100 Bronze Frogs
( Lithobates clamitans clamitans) from eastern Texas.
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page 14
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Figure 4. Monthly distribution of 25 calling records for Bronze Frogs ( Lithobates clamitans clami-
tans) from Brazos Bend State Park, Fort Bend County, Texas, during 1999-2004.
Month
Figure 5. The distribution of air (n = 25) and water (n = 22) temperatures associated with calling
by the Bronze Frog (Lithobates clamitans clamitans ) from Brazos Bend State Park, Fort Bend
County, Texas, during 1999-2004.
nn n
18 19 20 21 22 23 24 25
Temperature (C)
■ Air temp
□ Water temp
26 27 28 29
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Figure 6. The distribution of relative humidity values (n = 24) associated with calling by the
Bronze Frog ( Lithobates clamitans clamitans) from Brazos Bend State Park, Fort Bend County,
Texas, during 1999-2004.
developed in females varied across the months, whereby depletion of late-fall stores of fat w'as
evident in the spring and depleted by June (Figure 8). It was during April-June that the highest
numbers of gravid females were apparent (Figure 7), the majority of which were depleted of their
fat compared to their non-gravid counterparts (Figure 9).
The incidence of females containing food in their stomachs was relatively high through
the year but generally highest during September-March (Figure 8). The incidence of females
containing prey was lowest during April-August, concomitant with gravid females, the 41 .7% of
which were not eating (Figure 9).
Growth and sexual maturity.— The length of the larval period in eastern Texas could not
be ascertained: however, metamorphoslings were present in May and during August-November
(Figure 2, 1 0), and the distribution of body sizes w;as suggestive of a nearly continuous, production
of metamorphoslings in eastern Texas (Figure 10).
Body size at transformation of six metamorphoslings w'as small (mean = 22.2 + 3.4 mm
SVL) and ranged 18.6-27.2 mm SVL. From these data, growth trajectories from the monthly dis¬
tribution of body size indicated that male Bronze Frogs in eastern Texas reached sexual maturity
in four months of post-metamorphic age at 44.0 mm SVL (Figure 10). Males attained their mean
body size three or four months after reaching sexual maturity at 63.0 ±7.0 mm SVL; range =
44.0-80.7; n = 112).
Mean sex index (body length/tympanum) for 1 1 1 male Bronze Frogs was 7.4 + 0.62 mm
(range = 6. 1-8.7). Tympanum diameter co-varied with the body size of adult males (Figure 11)
page 16
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Figure 7. The annual ovarian cycle of 52 Bronze Frogs (Lithobates clamitans c lam i tans) from
eastern Texas.
Figure 8. Monthly frequency of extensive fat (n = 48) and the presence of food (n = 38) in female
Bronze Frogs ( Lithobates clamitans clamitans ) from eastern Texas.
Month
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Figure 9. Frequency of extensive fat (n = 48) and the presence of food (n = 48) in each of the four
ovarian stages of female Bronze Frogs (Lithobates clamitans clamitans) from eastern Texas.
100 n
12 3 4
Ovarian stage
Figure 10. Monthly distribution of body sizes of 272 Bronze Frogs ( Lithobates clamitans clamitans )
from eastern Texas.
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90 -
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Figure 11. The relationship between tympanum diameter and body size of 1 1 1 male Bronze Frogs
(Lithobates clamitans clamitans) from eastern Texas.
12
4 ' ' ‘‘ ■*,' ,J r ‘‘ - v - - - r - ■ ' ' - - — T- - -/
40 45 50 55 60 65 70 75 80 85
mm SVL
but not strongly enough that that a significant negative relationship existed between the sex index
and male body size.
The smallest sexually mature female (ovarian stage 1) reached sexual maturity at five
months of post-metamorphic age at 50.6 mm SVL (n = 11) (Figure 1 0). The smallest gravid female
measured 57.3 (// = 15), and was smaller than the smallest females of ovarian stages 2 (61.5 mm
SVL) and 3 (59.8 mm SVL). Mean body size for all sexually mature females was reached approxi¬
mately five or six months after reaching sexual maturity at 68.2 ±8.6 mm SVL (range = 50.6-85.9;
n = 53) mm SVL and their body sizes differed significantly in variance (F = 0.676; P < 0.04) and
mean (T = -3.883; df = 86; P < 0.000) from those of adult males.
Body sizes of gravid females (mean = 71.7 ± 7.1 mm SVL; range = 57.5-82.5; n - 15)
differed significantly in mean (T = -1.908; df = 51; P < 0.03) from those of non-gravid females
(ovarian stages 1-3) (mean = 66.8 ± 8.8 mm SVL; range = 50.6-85.9; n - 38).
Discussion
The Bronze Frog is the southern form of two recognized subspecies of the Green Frog,
a geographically widespread North American true frog (Conant and Collins 1998). The two forms
differ in color pattern (Mecham 1954) and in the smaller body sizes of adults (Wright and Wright,
1949; Mecham 1954) and metamorphoslings (Wright and Wright 1949). Bronze Frogs of northern
and southern Louisiana conformed to these findings of diminution of adult and metamorphosling
size (Meshaka et al. 2009a,b). Male Bronze Frogs in Louisiana were also smaller at minimum
and adult body size adult than females and they matured earlier than did females (Meshaka et al.
2009a, b). To that end, mean body size of both sexes was smaller in the southern part of the state.
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4 January-December 2011
The breeding season was longer in Louisiana than it was farther north in the geographic range of
the Bronze Frog (Meshaka et al. 2009a ,b)-
Findings of this study in eastern Texas were similar to those of Louisiana (Meshaka et
al. 2009a ,b) with respect to a smaller minimum and mean body size in males, an earlier maturity in
males, and a longer breeding season than in Bronze Frogs in northern latitudes. Specifically, however,
values of these traits in eastern Texas varied in similarity between northern and southern Louisiana.
For example, minimum body size of males at sexual maturity was larger in males from eastern Texas
(44.0 mm SVL) than in northern (40.7 mm SVL) and southern (39.9 mm SVL) Louisiana. Likewise,
minimum body size at sexual maturity in females was largest in eastern Texas (50.6 mm SVL) as
compared to northern (45.2 mm SVL) and southern (43.1 mm SVL) Louisiana. The smallest gravid
female from eastern Texas (57.3 mm SVL) was slightly smaller than that of northern Louisiana
(60.6 mm SVL) but both were larger than that of southern Louisiana (43.1 mm SVL).
The mean body size of eastern Texas males (63.0 mm SVL) was similar to that of northern
Louisiana (mean = 61.0 mm SVL) and larger than that of southern Louisiana (mean = 56.8 mm
SVL). Likewise, mean female body size in eastern Texas (68.2 mm SVL) was also larger than that
of Louisiana but more similar to the value from northern Louisiana (mean = 66.4 mm SVL) than
southern Louisiana (mean = 59.7 mm SVL).
Calling season in coastal Texas exceeded that of southern Louisiana by one month in Oc¬
tober. Calling in east, central, northern Texas began in March, like northern Louisiana, and ended in
September when the last of the Bronze Frogs were leaving breeding ponds in northwestern Louisiana.
The number of months in which gravid females were evident in eastern Texas was prolonged but
still fewer than either northern or southern Louisiana. However, limitations of a small sample size
from eastern Texas could not be ruled out as an explanation for this difference.
Consequently, the Bronze Frog of eastern Texas typified the small body size and longer
breeding season of this southern form and with varying degrees of similarity to those of northern
and southern Louisiana populations. The overall similarity of those traits between Texas and Loui¬
siana suggests to us that these traits were not altered by the causal factor or factors, perhaps such
as the natural edge of the Eastern Deciduous Forest in eastern Texas, responsible for the western
edge of its geographic range.
Acknowledgments
This study would not have been possible without the commitment of the aforementioned
institutions to collect and preserve amphibians and reptiles or without the willingness and time taken
by institutional staff to pack and ship these specimens for study. To that end, we wish to especially
extend our gratitude to Harold A. Dundee for his single-handed efforts in packing and shipping an
enormous lot of Bronze Frogs from Tulane. In addition, on 8 July 2004, on of the authors (WEM)
made the first e-mail research request ever sent out by The Center for North American Herpetol¬
ogy. It asked for information on the life history traits of Lithobates clamitans. The response was
overwhelming and the tremendous amount of data received through the CNAH request has added
to the value of this contribution.
Appendix 1. Specimens of Bronze Frogs (Lithobates clamitans clamitans) examined for this
study.
California Academy of Sciences 162741 ; Carnegie Museum of Natural history 121300; Field Museum of Natural History 74712,
94459, 94460; Illinois Natural History Survey, 378, 379, 380. 381 , 382, 383, 397, 398, 399, 523, 664. 665, 666, 667, 670, 673. 680, 12698. 1358.
1799, 18506, 18507. 18508.28715; Los Angeles County Museum of Natural History 1681, 1682, 1683, 13864, 13865, 13865, 13866,35039,35040,
35041.35042,35043,35044,35048,65371,65372,65373,65374,65375,65376,65377,65379,65380,65381,65383,65384,65385,91264.91265.
page 20
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
106890, 106891, 106892, 106893, 106894, 106895; Northwestern State University 3292, 4334; Texas Cooperative Wildlife Collection 72,74,75,
76, 77, 78, 1 058 , 2800, 2801, 2802, 2803 . 2804, 2805 , 2806. 2807, 2808, 2809, 28 1 0, 28 1 1 , 28 1 4, 28 1 5 , 28 1 7 , 28 1 8 , 282 1 , 2823 , 2824, 2825 ,4317,
4318. 4319, 4320, 4321 , 4322. 4980, 4981 . 4982, 4983, 5046, 5048. 5049, 5050, 5051 . 5052. 5053, 5054, 5055. 5956, 5957, 5959, 5960. 5961 ,
5962. 9061 , 9062, 9063; Texas Memorial museum 856, 1357, 1358. 1375, 2209, 2356. 2392, 2393, 2394, 2395, 2396, 2397, 7241 , 8640, 8640.
8642,8651.9208,9735, 12177,12178, 12179, 12180. 12181,12182, 12183, 12184, 12185, 14097, 14259, 15230, 15314, 18223, 18240, 18242,
18243. 18244. 18245, 18247, 18248, 18250, 18251, 18252, 18254, 18255, 18256, 18257, 18258. 18259. 18260.20602.21443,21446,22045.22046.
22047,22048,22259,22347,22349.24869,25540,25738,25739,25740,29035,29136,30822,30823,30824.33169.33170,33171,33172,36337.
44278. 46320, 52080. 55224, 55401 . 55446, 56007; Tulane University 14396, 15636. 15636, 16756. 17323, 22041 . 22054, 22059, 22061 , 22072,
22073,30608.30616, 30617, 30618,30619, 30620, 30621 , 30622. 30646,30647. 30648. 30649. 30650. 3065 1 . 30652,30653, 30654, 30655,30656,
30657. 30658, 30659, 30660. 30677. 30678, 30679, 30707. 30758, 31 107, 31 108, 3 1 1 14, 3 1 1 15, 31 1 16, 31 1 19, 3 1 120, 3 1 13 1 , 3 1264; University of
Arizona 42329; University of Kansas Biodiversity Institute 60615. 60616, 60617. 60618, 60619, 289459. 289515; University of Michigan 70358.
77630.77630,77630, 102206. 102206, 105257, 1 15845, 1 15845. 115846,115847, 16771, 116771. 116771, 1 16772, 1 16772; University of Texas-EI
Paso 8580, 12213, 14004.
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1931 . Life-Histories of the Frogs of the Okefinokee Swamp, Georgia. New York,
The McMillan Company.
- and A. A. Wright. 1949. Handbook of Frogs and Toads of the United States and Canada.
New York, Cornell University Press.
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Walter E. Meshaka , Jr., Section of Zoology and Botany, State Museum of Pennsylvania,
300 North Street, Harrisburg, PA 17120
Samuel D. Marshall, Department of Biology, Northwestern State University,
Natchitoches, LA 71497
David Heinicke, Texas Parks and Wildlife Department, Brazos Bend State Park ,
21901 F.M. 762, Needville, TX 77461
Received: 1 March 201 1
Accepted: 4 June 2011
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Seasonal Activity, Reproductive Cycles, and Growth
of the Northern Leopard Frog, Lithobates pipiens
(Schreber, 1782), From Pennsylvania
Abstract
An examination of 478 museum specimens of the Northern Leopard Frog ( Lithobates
pipiens ) collected during 1896-1985 from Pennsylvania provided comparative life history data
from the southeastern edge of its geographic range. Activity occurred during March-October, with
breeding in the spring. The larval period lasted two to three months, and both sexes reached sexual
maturity within one year of transformation at about 50 mm snout-vent length. Sexual maturity was
reached before the first year of post-metamorphic age, but all individuals were breeding just before
reaching two years of post-metamorphic age. In most respects, reproduction and growth of this
species in Pennsylvania were more similar to populations at similar latitudes than more northerly
populations. These differences quantify variability in life history traits which in turn are necessary
data when formulating region-specific management plans.
Introduction
The Northern Leopard Frog, Lithobates pipiens (Shreber, 1782), is a geographically
widespread frog primarily in southern Canada and northern regions of the United States (Conant
and Collins, 1998). In Pennsylvania, it occurs primarily in the northern and western counties (Hulse
et al., 2001 ; Meshaka and Collins, 2010), which for the species approximates the southeastern edge
of its geographic range (Conant and Collins, 1998: Rorabaugh, 2005). The species ranges farther
south in the American West (Conant and Collins, 1998; Rorabaugh, 2005). In summary of the
literature Rorabaugh (2005) reported oviposition having generally occurred during a short period
in the spring, with exceptions in the southwest, clutch sizes having ranged 648-7648 eggs, and
tadpoles having transformed within a wide range of body sizes within three to six months follow¬
ing egg deposition. Age at sexual maturity was generally delayed to two to three years, especially
in females, with some individuals, especially males having matured, in less than two years of age
(Rorabaugh, 2005).
Very few published data are available for the ecology of this frog in Pennsylvania, where
it is listed as a species of Greatest Conservation Need (Morris, 2010). In light of its status in Penn¬
sylvania, paucity of life history information in the state, and variation in life history traits over its
large geographic range, we undertook this study to provide region-specific information to both bet¬
ter understand the patterns of its geographic variation in its life history traits near the southeastern
edge of its geographic range and to provide the sorts of region-specific information necessary in
formulating effective management plans for this sensitive Pennsylvania species.
Materials and Methods
We examined 478 specimens of Northern Leopard Frogs ( Lithobates pipiens) that were
collected during 1898-1985 from 24 of the 67 Pennsylvania counties from the holdings of the
Carnegie Museum of Natural History in Pittsburgh and the State Museum of Pennsylvania in Har¬
risburg (Figure l).The majority of these specimens, 6 1 .1%, were collected from Allegheny County.
Body lengths of all frogs and tadpoles were measured in mm snout-vent length (mm SVL) to the
nearest 0.1 mm using calipers.
Key words: Anuran breeding, clutch sizes, geographic variation, species management.
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Sexual maturity in males was determined by the presence of enlarged testes and enlarged
thumbs. Length and width of the left testis as a percent of the body size was used to measure seasonal
differences in testis dimensions. Monthly frequencies of enlarged thumbs also served as a measure
of seasonal patterns of fertility .
Sexually mature females were associated with one of four ovarian stages. In the first
ovarian stage oviducts were thin and just beginning to coil, and the ovaries are somewhat opaque.
In the second ovarian stage, the oviducts were larger and more coiled, and the ovaries contained
some pigmented oocytes. In the third ovarian stage, oviducts were thick and heavily coiled, and the
ovaries were in various stages of clutch development. In the fourth ovarian stage, oviducts were
thick and heavily coiled, and the ovaries were full of polarized ova with few non-polarized ova.
signifying a fully ripened clutch and gravid female (Meshaka 2001).
Fat body development was scored as absent, intermediate in volume in the body cavity,
to extensive development that reached upwards in the body cavity. The latter amount was used as
an estimation monthly incidence of extensive fat relative to all females examined in each month.
A subset of females was examined for clutch characteristics. Clutches were removed,
patted on paper towel to remove excess moisture, a subset of ova was weighed on an electronic
scale to the nearest 0.1 g, and that mass was extrapolated to estimate clutch size. From each clutch,
the diameters of 10 ova were measure using an ocular micrometer; the largest ovum was used in
comparative relationships with clutch size and female body size.
Tadpoles from were scored as per Gosner (1960). For practical puiposes, tadpoles were
in categories of having poorly-developed hind legs (less than Gosner stage 37) or well-developed
hind legs (Gosner stage of at least 37). Metamorphoslings were distinguished from tadpoles by
the presence of forelimbs (Gosner stage 42) and distinguished from juveniles by the presence of a
tail. Statistical analysis was conducted with the use of Excel. Because body size differences were
expected in our comparisons, one-tailed t-tests were used to compare means between samples. F-
tests were calculated to determine significant differences in variance of samples. Significance was
recognized at P < 0.05. Means were followed by ± 1 standard deviations.
Results
Seasonal activity - Over a period of 87 years, Northern Leopard Frogs were collected
during February-October (Figure 2). Males were most apparent in collections in March and April
and less so again in September (Figure 2a). Small samples hampered detection of seasonal trends
in numbers of females; however, more females were captured in March than in February, with
many more having been detected in September (Figure 2a). Thus, for sexually mature individuals,
March, April, and September were peak months in their detectability (Figure 2a). On the other hand,
juveniles were most apparent in July and somewhat less so in August, although juveniles were ap¬
parent during March-October (Figure 2a). Tadpoles and most metamorphoslings were detected in
July (Figure 2b). A few metamorphoslings were detected in June and August (Figure 2b).
Seasonal changes in testis size- The monthly distribution of testis length as a percentage
of snout-vent length was indicative of an apparent decrease from spring into summer, followed by
a fall increase in dimensions (Figure 3).
Male thumbs - In all months except May, enlarged thumbs were present on at least 75%
of the males (Figure 4). Enlarged thumbs were detected in all spring-emergent males and those
captured at the end of the active season (Figure 4).
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Figure 1. Twenty-four of the 67 Pennsylvania counties from which specimens of the Northern
Leopard Frog, Lithobates pipiens, were examined in this study.
Male fat and presence of food- The monthly percentage of males with extensive fat de¬
velopment never exceeded 50% of the monthly sample, and both spring and fall samples contained
few males with extensive fat development (Figure 5). May samples contained the fewest males
containing extensive coelomic fat (Figure 5). The monthly percentage of males containing food was
greater in August and September than at other times of the year. Two thirds of males captured near
the end of their active season contained food as compared to the earliest collections in March in
which only slightly more than one third of the sample had yet eaten since emergence (Figure 5).
Ovarian cycle.- The highest number of gravid females were found in March and April,
although some gravid females were found in July and September as well (Figure 6). Females cap¬
tured at the end of their active season were in various stages of follicular development, including
nearly gravid (Figure 6).
Clutch characteristics - Ten females (mean = 85.4 + 8.42 mm SVL; range = 66.8-95.0)
produced a mean clutch size of 3009.3 eggs (std. dev. = 852.02; range = 1512-4040). The relation¬
ship between clutch size and female body size was positive but not significant (p > 0.05). The mean
ovum diameter of 100 ova from 10 gravid females measured 1.77 mm (std. dev. = 0.35; range =
1 .1-2.8). The relationship between mean ovum size female body size was positive and significant
(p < 0.01) (Figure 7); however, the relationship between mean ovum diameter and clutch size was
positive but not significant (p > 0.05).
Female fat and presence of food- The highest incidence of extensive fat among sexually
mature females was found in yolking females of stages 2 and 3 (Figure 8). Fully gravid (stage 4)
and reproductively quiescent females (stage 1) were least likely to contain extensive fat (Figure 8).
The frequency of females containing food declined as follicular development advanced, such that
gravid females, whose body cavities were filled with ripe eggs, comprised the segment of females
with the lowest incidence of food (Figure 8).
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Figure 2. Seasonal incidence of capture of 478 Northern Leopard Frogs {Lithobates pipiens) from
Pennsylvania. A = males (n = 54), females (n = 44), and juveniles (n = 204). B = tadpoles with
poorly developed rear legs (n = 21), tadpoles with well-developed rear legs (n = 49), and meta-
morphoslings (n = 106).
Month
Month
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Figure 3. Monthly distribution of testis size as a percentage of snout-vent length of 54 Northern
Leopard Frogs ( Lithobates pipiens ) from Pennsylvania.
15
14
13
12
11
10 -
9 -
8 -
7 -
6 -
5 -
4
3 1
2
1
0
♦ Testis length
o Testis width
5 6
Month
10
Figure 4. Monthly frequencies of enlarged thumbs in 54 male Northern Leopard Frogs ( Lithobates
pipiens ) from Pennsylvania.
Month
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4 January-December 2011
Figure 5. Monthly frequency of extensive fat and the presence of food in 54 male Northern Leopard
Frogs ( Lithobates pipiens ) from Pennsylvania.
Month
Figure 6. The annual ovarian cycle of 44 Northern Leopard Frogs ( Lithobates pipiens ) from
Pennsylvania.
Month
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Figure 7. The relationship between mean ovum diameter and female body size in 10 female Northern
Leopard Frogs ( Lithobates pipiens ) from Pennsylvania.
o -I - 1 - 1 - 1 - i - 1 - 1 - i - 1
60 65 70 75 80 85 90 95 100
SVL (mm)
Figure 8. Frequency of extensive fat and the presence of food in each of the four ovarian stages of
42 female Northern Leopard Frogs ( Lithobates pipiens ) from Pennsylvania.
Ovarian stage
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
The monthly incidence of females containing extensive fat was highest just before hi¬
bernation (Figure 9). With the exception of a spike in this value in July, the pattern appeared to be
one of depletion apparent in spring and early summer, which was followed by accumulation of fat
from late summer onward (Figure 9). Except in early spring, monthly incidence of males containing
prey was high throughout the active season (Figure 9).
Growth and sexual maturity - Across Pennsylvania metamorphoslings were present in
July and August (Figure 2, 10), indicating an approximately three month larval period after April
and May breeding. Body sizes of metamorphoslings ranged 17.1-41.7 mm SVL (mean = 24.1 +
3.9 mm SVL; n = 106). The monthly distribution of body sizes (Figure 10) suggests that males
reached a minimum body size of 47.1 mm SVL within 12 months of larval transformation. Males
reached their mean body size of 65.8 mm SVL (std. dev. = 7.9 mm SVL; range = 47.1-79.1; n =
54) at approximately 24 month of postmetamorphic age (Figure 10).
The smallest females that were yolking measured 49.0 (ovarian stage 2) and 53.0 mm SVL
(ovarian stage 3). The smallest reproductively quiescent female (ovarian stage 1) measured 49.2
mm SVL, and the smallest gravid female (ovarian stage 4) measured 66.8 mm SVL. The monthly
distribution of body sizes (Figure 10) east 49 mm SVL within one year of post-metamorphic age.
However, all femalesizes (Figure 10) suggests that females could reach sexual maturity of at least 49
mm SVL within one year of post-metamorphic life. However, all females would be ready to breed
in spring when 20-22 months of post-metamorphic age (Figure 10) at a body size near the smallest
gravid female we examined and the mean adult body size of sexually mature females (mean = 71 .5
+ 14.1 mm SVL: range = 49.0-95.3: n = 47).
Figure 9. Monthly frequency of extensive fat and the presence of food in 39 female Northern
Leopard Frogs ( Lithobates pipiens) from Pennsylvania.
100 i
90 -
80 -
70 -
60
50 *
<u 40
CL
30 -
20 -
10
0
□ Females with extensive fat
M Females with food _
5 6 7
Month
10
12
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Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
The mean body size, but not the variance (F-test, P> 0.05) of 15 gravid females (mean =
84.8 ±8.6 mm SVL; range = 66.8-95.0) was significantly larger (t = 1 .679, df = 45, p < 0.001) than
that of non-gravid counterparts (mean = 65.3 ± 1 1 .7 mm SVL; range = 49.0-87.8; n = 32). Among
all sexually mature adults, significant differences were found in the variance (F= 3.175, P < 0.001)
and mean (t = -2.480, df = 70, p < 0.001) of body size between in males and females.
Discussion
The geographic range of the Northern Leopard Frog ranges southward from southern
Quebec and extreme south of the District of Mack to New Mexico and Kentucky (Conant and Col¬
lins, 1998), thereby placing Pennsylvania near the southern edge of its geographic range.
Pennsylvania populations were active during February-October with collections of adults
exhibiting a bimodal distribution in numbers. An active season of March-October has been reported
for the species in both New England (Klemens, 1993) and Missouri (Johnson. 1987).
The March- April amplitude in collections in Pennsylvania overlapped the egglaying season
of this species. Females over-winter with eggs, and although gravid females were detected in July,
the distribution of body sizes of juveniles, does not support breeding at that time. Evidence of spring
breeding in Pennsylvania coincided with the generally short breeding season in the spring that typi¬
fied breeding for the species in the United States, with a few notable exceptions in the Southwest
(Rorabaugh, 2005). A summary of breeding dates corroborated a general pattern of spring breeding
in the species but with a noticeable shift towards beginning and ending later in northern populations:
March in Indiana (Minton, 2001) and Massachusetts (Klemens, 1993), March- April in Massachusetts
Figure 10. Monthly distribution of body sizes of males (n = 54), females (n = 44), juveniles (n =
204), and metamorpholsings (n = 106) of the Northern Leopard Frog ( Lithobates pipiens ) from
Pennsylvania.
100 -
90 -
80 -
70 -
60 '
40 -
30 -
20 -
10 -
0 "
0
B
□
B
□
9
!
t
3
□
□
♦
0
I
I
X
X
□
B
n
a
□
□
t
♦
x
x
0
□
a
□
x
£
X
□
3 D
9
i □
□
B
X
♦ Male
D Female
x Juvenile
* Four-leaaed with tail
□
□
□
i
0
2 3 4 5 6 7 8 9 10 11 12
Month
Bulletin of the Maryland Herpetoiogical Society
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Volume 47 Numbers 1-4
January-December 2011
(Dunn, 1930) and West Virginia (Green and Pauley, 1987), March-May in Illinois (Smith. 1961),
April in Wisconsin (Vogt, 1981), April -June in Alberta, Canada (Russell and Bauer, 2000).
The Southern Leopard Frog, Lithobates sphenoceophalus (Cope, 1886), occurs in south¬
eastern Pennsylvania, sympatrically with the Northern Leopard Frog in one county (Hulse et al.,
2001 ; Meshaka and Collins, 2010). Like the Northern Leopard Frog, the southern form occurs over
a large geographic range, where it replaces its northern congener in the American South (Conant
and Collins, 1998; Butterfield et al., 2005). When we compared the breeding seasons of both spe¬
cies, we found that the breeding seasons of these two species were more similar to one another
in Pennsylvania than they were to those of conspecifics at their respective geographic extremes.
For the Southern Leopard Frog, breeding occurred primarily in April in Pennsylvania and during
February-April in Delmarva (White and White, 2002): Generally spring up north and any time in
the South, especially fall and again in spring (Butterfield et al., 2005).
Clutch size estimates for the Northern Leopard Frog have been reported to range 645-
7645 eggs (Rorabaugh, 2005), and our estimates in range and mean fall within that range. In light
of the large clutches and short breeding season in Pennsylvania, multiple clutch production seemed
unlikely to us, which had it occurred, could have explained the absences of a significant relationship
between clutch and female body size. More likely the small sample size could better explain the
biologically meaningful even if not statistically significant positive trend in this relationship. On
the other hand, ovum diameter increased with female body size, which we would have predicted
would be reflected in the relationship between clutch and ovum size. Here again, a small sample
size could explain the absence of significance in an otherwise weakly positive association. Ovum
size in our sample, like clutch size, was similar to values provided from elsewhere in its geographic
range: About 1 .7 mm in Alberta (Russell and Bauer, 2000), 1 .0- 1 .8 mm Wisconsin (Vogt, 1 98 1 ), an
average of 1 .7 mm in Ohio (Walker, 1946).
Two to three months of larval growth was estimated for our sample. Our estimation for
larval period for Pennsylvania Northern Leopard Frogs was similar to the estimates of 2-3 months in
Indiana (Minton, 200 1 ) and 70- 1 00 days in Wisconsin (Vogt. 1 98 1 ).Body size at transformation can
vary widely in this species (Rorabaugh, 2005). Average body size of metamorphoslings in our sample
was similar to the 25 mm average from a Quebec sample (Leclair and Castanet, 1987). However, the
range in body sizes of metamorphoslings from our study ranged greater than that of the 25-32 mm
range in Indiana (Minton, 2001 ) and ranged smaller than the 35-40 mm range that typified samples
from Minnesota (Merrell, 1977). Transformation times in Pennsylvania were similar to the months
of June-July in Wisconsin (Vogt, 1981), and June-August in Illinois (Smith, 1961).
In Pennsylvania, males and females matured at small body sizes and, once mature, mean
body sizes of females were significantly larger than that of males. A comparison of body sizes among
adults of males (mean = 63 mm; range = 51-87) and females (mean = 69.0 mm; range = 54-89) in
Indiana (Minton, 2001) and males (mean = 57.2 mm; range = 51-65) and females (mean = 57.0
mm: range = 53-65) in Connecticut (Klemens, 1993) indicated that minimum body sizes among
sites were variable within a small range, especially for males. However, unlike those of Connecti¬
cut (Klemens, 1993), Northern Leopard Frogs in both Indiana and our sample from Pennsylvania
exhibited strong sexual dimorphism in body size with similarly strong male/ female body size ratio
of 0.91 in Indiana (Minton, 2001) and 0.92 in our sample.
Like transformation size, age to sexual maturity in the Northern Leopard Frog varies widely
across its geographic range. In Pennsylvania, the earliest hatching males and females were sexually
mature in time to breed the following spring before reaching their first year of post-metamorphic life.
Most individuals, however, reached sexual maturity after their first spring of post-metamorphic life,
thereby missing breeding until their second spring just shortly before two years of post-metamorphic
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4 January-December 2011
life. For most populations. Northern Leopard Frogs reached sexual maturity at two to three years of
age (Rorabaugh. 2005). Comparatively, in Ithaca, New York, maturity of a few individuals could
be reached in the same year as metamorphosis (Ryan, 1953), and in Wisconsin males could reach
sexual maturity in as early as one year after metamorphosis but generally at two years of age (Hine
et al., 1981). Sexual maturity was attained at three years of age in northern Michigan (Force, 1933)
and in two to three years after transformation in Alberta. Canada (Russell and Bauer, 2000).
In Pennsylvania, the Northern Leopard Frog is listed as a Species of Greatest Conserva¬
tion Need (Morris, 2010), and a search through the literature has revealed very little work on any
Pennsylvania populations. Consequently, this paper could represent a starting point in understanding
the range of variability in the most basic of life history traits in Pennsylvania populations as well
as a reference source for protocols to make detection for inventorying and monitoring this species
more effective for researchers in Pennsylvania. This latter point is critical in light of regional and
geographic variation evident in life history traits examined in this study.
Acknowledgments- A debt of gratitude goes to Steve Rogers, Collections Manager at the
Carnegie Museum of Natural History, for the loan of specimens. WEM extends his gratitude to
Jack Leighow, former Director of the State Museum of Pennsylvania, and to David Dunn, acting
Director of the State Museum, for their support in his research endeavors.
Literature Cited
Butterfield, B.P.. M.J. Lannoo, and P. Nanjappa.
2005. Rana sphenoceophala Cope, 1886: Southern Leopard Frog. Pp. 586-587 In
M. Lannoo, editor. Status and Conservation of North American Amphibians.
University of California Press. Berkeley, California. 1094 pp.
Conant, R. and J.T. Collins.
1998. Reptiles and Amphibians of Eastern/Central North America. 3rd ed. Houghton
Mifflin Co. New York. New York. 616 pp.
Dunn, E.R.
1 930. Reptiles and amphibians of Northampton and vicinity. Bulletin of the Boston
Society of Natural History 57:3-8.
Force, E.R.
1933. The age of attainment of sexual maturity of the leopard frog, Rana pipiens
Schreber, in northern Michgian. Copeia 1933:128-131 .
Gosner, K.L.
1960. A simplified table for staging anuran embryos and larvae with notes on
identification. Herpetologica 16:183-190.
Green, N.B. and T.K. Pauley.
1987. Amphibians and reptiles in West Virginia. 1987. University of Pittsburgh
Press. Pittsburgh, Pennsylvania. 241 pp.
Hine, R.L.. B.L. Less, and B.F. Hellmich.
1981 . Leopard frog populations and mortality in Wisconsin, 1974-1976. Wisconsin
Department of Natural Resources, Technical Bulletin No. 122. Madison,
Wisconsin. 39 pp.
Bulletin of the Maryland Herpetological Society
page 33
Volume 47 Numbers 1-4
January-December 2011
Hulse, A.C., CJ. McCoy, and E.J. Censky.
2001 . Amphibians and Reptiles of Pennsylvania and the Northeast. Cornell Uni-
versity Press. Ithaca, New York. 419 pp.
Johnson, T.R.
1987.
The Amphibians and Reptiles of Missouri. Missouri Department of Conser¬
vation, Jefferson City, Missouri. 368 pp.
Klemens, M.W.
1993.
Amphibians and Reptiles of Connecticut and Adjacent Regions. State Geo¬
logical and Natural History Survey of Connecticut, Bulletin No. 112. 318
pp.
Leclair R., Jr. and J. Castanet
1987.
A skeletochronological assessment of age and growth in the frog Rcinci pipiens
Schreber (Amphibia, Anura) from southwestern Quebec. Copeia, 1987:361-
369.
Merrell. D.J.
1977.
Life history of the leopard frog in Minnesota. Occasional Papers of the Bell
Museum of Natural History. University of Minnesota, 15:1-23.
Meshaka, W. E.,Jr.
2001.
The Cuban Treefrog in Florida: Life History of a Successful Colonizing
Species. University Press of Florida. Gaineseville, Florida, 191 pp.
Meshaka, W. E., Jr., and J. T. Collins.
2010.
A Pocket Guide to Pennsylvania Frogs and Toads. Mennonite Press, Newton.
Kansas. 40 pp.
Minton, S.A., Jr.
2001.
Amphibians and Reptiles of Indiana. Revised 2nd edition. Indiana Academy
of Science. Indianapolis, Indiana. 404 pp.
Morris, K.M.
2010.
Northern Leopard Frog. Pp. 87-89 In M.A. Steele. M.C. Brittingham, T.J.
Maret, and J.F. Merritt, editors. Terrestrial Vertebrates of Pennsylvania: A
Complete Guide to Species of Conservation Concern. John Hopkins Uni¬
versity Press. Baltimore, Maryland. 507 pp.
Rorabaugh, J.C.
2005.
Rcmci pipiens Schreber, 1782: Northern Leopard Frog. Pp. 570-577 In M.
Lannoo, editor, Status and Conservation of North American Amphibians.
University of California Press. Berkeley, California. 1094 pp.
Russell, A. P. and A.M. Bauer.
2000. The Amphibians and Reptiles of Alberta: A Field Guide and Primer of Boreal
Ryan, R. A.
1953.
Herpetology. University of Calgary Press. Alberta, Canada. 279 pp.
Growth rates of some ranids under natural conditions. Copeia 1953:73-80.
page 34
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Smith, P.W.
1961. The Amphibians and Reptiles of Illinois. Illinois Natural History Survey
Bulletin, volume 28, Article 1 . 298 pp.
Vogt, R.C.
1981. Natural History of Amphibians and Reptiles of Wisconsin. Milwaukee Public
Museum. Milwaukee, Wisconsin. 205 pp.
Walker, C.F.
1946. The amphibians of Ohio. Part 1 : The frogs and toads (Order Salientia) Ohio
State Museum of Science Bulletin, 1:1-109.
White, J.F. Jr. and A.W. White.
2002. Amphibians and Reptiles of Delmarva. Tidewater Publishers. Centreville,
Maryland. 248 pp.
Walter E. Meshaka, Jr., Section of Zoology and Botany, State Museum of Pennsylvania,
300 North Street, Harrisburg, PA 17120, wmeshaka@state.pa.us
Pablo R. Delis, Department of Biology, Shippensburg University, 1871 Old Main Drive,
Shippensburg, PA 17257.
Sarah A. Mortzfeldt, Section of Zoology and Botany, State Museum of Pennsylvania,
300 North Street, Harrisburg, PA 17120.
Received: 26 May 2011
Accepted: 18 July 2011
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
Clutch characteristics of the Southern Leopard Frog,
Lithobates sphenocephalus (Cope, 1886),
in Natchitoches, Louisiana
Walter E. Meshaka, Jr. and Samuel D. Marshall
The Southern Leopard Frog, Lithobates sphenocephalus (Cope, 1886) is an inhabitant
of much of the United States, including Louisiana (Dundee and Rossman, 1989; Conant and Col¬
lins, 1991; Butterfield et al., 2005). In southern Louisiana, eggs are laid throughout the year with
most reproductive activity occurring during December-February (Dundee and Rossman, 1989). In
Louisiana, egg masses in the form of a plinth contain 1000- 1500 eggs (Dundee and Rossman, 1989).
Here, we provide clutch characteristics of six Southern Leopard Frogs from Natchitoches Parish,
Louisiana. Specimens were derived from the vertebrate collection of Northwestern State University,
Natchitoches, Louisiana, from females collected in February and April 1 969 and February and June
1971 . Female body size was measured in mm snout- vent length (SVL). Clutch size was estimated
by weighing a subset of mature ova. Means are followed by + 2 standard deviations.
Estimated clutch size of six gravid females (mean= 69.5 ± 7.70 mm SVL; range= 59.5-
82.3) averaged 1585.4 ± 568.34 eggs (range= 975-2367.5). Clutch sizes in Natchitoches were
smaller than those of northeastern Arkansas where clutch sizes of 39 females (51-89 mm SVL)
averaged 2958.7 eggs (range = 1700-5537) (Trauth, 1989). However, too few gravid females were
available from Natchitoches to make meaningful comparisons, and these findings underscore the
opportunity that exists to conduct field and museum studies on this poorly studied but relatively
common frog in Louisiana.
Literature Cited
Conant, R. and J.T. Collins.
1998. Reptiles and Amphibians of Eastern/Central North America. 3rd ed. Houghton
Mifflin Co. New York, New York. 616 pp.
Butterfield, B.P., M.J. Lannoo, and P. Nanjappa.
2005. Rana sphenocephala Cope, 1886: Southern Leopard Frog. Pp. 586-587. In
M. Lannoo, editor, Status and Conservation of North American Amphibians.
University of California Press. Berkeley, California. 1094 pp.
Dundee, H.A. and D.A. Rossman.
1989. The Amphibians and Reptiles of Louisiana. Louisiana State University Press.
Baton rouge. Louisiana. 300 pp.
Trauth, S.E.
1 989. Female reproductive traits of the southern leopard frog, Rana sphenocephala
(Anura: Ranidae), from Arkansas. Proceedings of the Arkansas Academy of
Science 43: 105-108.
page 36
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Walter E. Meshaka , Jr., Section of Zoology and Botany, State Museum of Pennsylvania, 300
North Street , Harrisburg, PA 17120, U.S.A. wmeshaka@state.pa.us [author for correspondence]
Samuel D. Marshall, Department of Biology, Northwestern State University, Natchitoches, LA
71497, U.S.A.
Received: 23 March 201 1
Accepted: 5 May 20 1 1
Bulletin of the Maryland Herpetological Society
page 37
Volume 47 Numbers 1-4
January-December 2011
The Effects of Temperature and Salinity on Wood Frog
(Lithobates sylvaticus) Tadpole Growth and Survival
Abstract
Increased levels of road salt runoff in combination with increased temperatures
earlier in the spring could create stressful environments for wood frog ( Lithobates syl¬
vaticus) tadpoles. We examined the effects of salinity and temperature as stressors, both
independently and jointly. We used three concentrations of NaCl (control . low, and high)
and two temperature treatments. Higher temperature resulted in significantly decreased
survivorship, but did not affect mean tadpole mass. Salinity did not have any significant
effects, nor did the interaction of salinity and temperature. These results suggest wanning
trends may have greater effects on this population than changes in salinity.
It is common for northern temperate regions to have salt-contaminated freshwater habitats
due to the frequent use of road deicing compounds (e.g., Kaushal et al., 2005). Such salt-contami¬
nation can cause stunted growth, slower rates of metamorphosis, and decreased survival of anuran
larvae (Dougherty and Smith, 2006; Collins and Russell, 2009; Langhans et al.. 2009). however
some species or populations of anurans are relatively tolerant of salt-contamination (e.g., Dougherty
and Smith, 2006; Karraker, 2007; Collins and Russell, 2009). Indeed, some species appear to be
prevented from occupying ponds contaminated with road salt, whereas other species appear to be
able to occupy them (Collins and Russell, 2009).
Temperature is another factor that can affect the performance of anuran larvae. However,
the effects of temperature on anuran tadpoles can be variable, with increased temperatures shown
to decrease tadpole growth in some species (e.g., Alvarez and Nicieza, 2002; Orizaola and Laurila,
2009) and increase tadpole growth in other species (e.g., Sanuy et al., 2008; Castano et al., 2010).
Temperature can also affect survivorship in tadpoles, with higher temperatures sometimes resulting
in lower survivorship (e.g., Castano et al., 2010) or higher survivorship (e.g., Sanuy et al., 2008;
Orizaola and Laurila, 2009).
Wood frogs ( Lithobates sylvaticus ) are a common and widespread frog in northeastern
North America that inhabit vernal pools (Redmer and Trauth, 2005). This is a region where sali¬
nization of freshwater is important (Kaushal et al., 2005). Given that wood frogs are early spring
breeders (Redmer and Trauth, 2005), they are likely to be affected by both road salt contamination
and any warming trends associated with global climate change. Previous studies have found that
wood frogs are susceptible to the effects of salt-contamination, but the concentrations that increase
mortality or affect growth can vary among populations (e.g.. Collins and Russell, 2009; Langhans
et al., 2009; Petranka and Doyle, 2010). Road salt can also have significant demographic effects on
wood frog populations (Karraker et al., 2008). Considering temperature, Castano et al. (20 10) found
that the survivorship of wood frog tadpoles from Ohio was better at 17°C than at 25°C; however,
they found that tadpoles at 25°C were larger than tadpoles at 17°C.
To our knowledge, no previous study has examined the potential interaction between salt
contamination and temperature on the performance of wood frog tadpoles. Such information may al¬
low us to better understand the potential impacts of these environmental stressors on wood frogs.
page 38
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
To this end, we examined how the combination of increased salinity and increased water
temperature may affect the growth and survivorship of wood frog tadpoles.
Materials and Methods
We collected wood frog egg masses (N = 6) from a local pond within 24 h of oviposition.
We incubated the eggs in the laboratory until hatching. Upon hatching, tadpoles were maintained
in large plastic containers where tadpoles from the different clutches were allowed to mix. We
began the experiment once tadpoles reached Gosner Stage 26 (Gosner, 1 960) and had a mean mass
of 0.023 ± 0.001 g (N = 10).
The experiment was a 3 x 2 fully factorial design with three salinity treatments (control,
low, and high) and two temperature treatments (25°C and 30.5°C) replicated 6 times. For the salin¬
ity treatments, we created stock solutions of the low (500 mg NaCl/L) and high ( 1 000 mg NaCl/L)
salinity treatments using NaCl (Fisher Scientific Sodium Chloride Certified for Biological Work)
and aged tapwater. Temperature treatments were created by placing the containers in either a ther¬
mostat controlled lab (25°C) or a thermostat controlled greenhouse (30.5°C). Each experimental unit
consisted of a clear plastic container (21 cm x 14 cm x 5 cm) filled with 500 mL of the appropriate
salinity solution. Each container had 5 tadpoles.
Every 3 days we refilled each container with water of the appropriate salt concentration
that had been acclimated to the treatment temperature. We also removed feces and any remaining
food. We fed the tadpoles 0.05g of crushed Purina Rabbit Chow per tadpole every 3 days. After 10
days, we recorded the number of tadpoles alive in each container and weighed the survivors to the
nearest 0.001 g after blotting dry. We used two-way ANOVAs to analyze the effects of temperature
and salinity on tadpole mass and survivorship separately.
Results
Survivorship to the end of the experiment was higher in the 25 °C treatments than in the
30.5°C treatments (25°C: 0.80 ± 0.063 |N = 18|. 30.5°C: 0.267 ± 0.096 [N = 18]; F],30 = 22.26,
P < 0.0001). Salinity had no effect on tadpole survivorship (Control: 0.65 ± 0.14 [N = 12], Low:
0.47 ± 0.12 [N = 12], High: 0.48 ±0.11 [N = 12]; F2,30 = 1 -49, P = 0.24). The interaction between
temperature and salinity was not significant (F2,3o = 1.18, P = 0.32).
Mean tadpole mass was not significantly affected by temperature treatment (25°C: 0.0530
± 0.0037 g |N = 17], 30.5°C: 0.0614 ± 0.0085 g [N = 6]; FU7 = 1.05, P = 0.32). Mean tadpole
mass was also not affected by salinity treatment (Control: 0.052 ± 0.0009 g [N = 8], Low: 0.053
± 0.006 g [N = 7], High: 0.060 ± 0.009 ]N = 8]; F2,]7 = 0.98, P = 0.40). The interaction term was
not significant (F2,i7 = 0.50, P = 0.6 1 ).
Discussion
Our results indicate that NaCl concentrations of 500 and 1000 mg L-i did not affect the
growth or survivorship of wood frog tadpoles. This is in contrast to other studies that have found
salinity to negatively affect survivorship, growth, and size at metamorphosis in wood frogs at con¬
centrations ranging up to 1400 mg L-t (Sanzo and Hecnar, 2006; Karraker et al., 2008). However,
Petranka and Doyle (2010) found increased mortality in wood frog tadpoles only at concentra¬
tions of 4500 mg L-1 and no effect at lower concentrations. Thus, there appears to be a range of
susceptibility to salinity in wood frog tadpoles across their geographical range. What drives such
variability in susceptibility is unknown but warrants further investigation.
Bulletin of the Maryland Herpetological Society
page 39
Volume 47 Numbers 1-4
January-December 2011
The survivorship of wood frog tadpoles at 25°C was greater than their survivorship at
30.5°C, but mean tadpole mass did not differ between the temperatures. Castano et al. (2010) found
that survivorship of wood frog tadpoles was better at 17°C than at 25°C; however, they found that
tadpoles at 25°C were larger than tadpoles at 17°C. Our results for survivorship are generally
consistent with Castano et al. (2010) in that survivorship is better at the cooler temperature. Our
results are also consistent with the observation that 25°C is near the maximum tolerated temperature
for wood frog tadpoles from Ohio (Manis and Claussen, 1985). Thus, higher temperatures appear
to negatively affect survivorship in wood frog tadpoles. However, our results for mass and those
from Castano et al. (2010) suggest that growth in wood frog tadpoles in this Ohio population is
generally better at higher temperatures since growth at 25°C was greater than at 17°C (Castano et
al., 2010) and similar to that at 30.5°C (this study). The results of these two experiments do suggest
that increasing temperatures associated with a warming climate could have serious consequences
for wood frogs, especially since the increases in growth performance appear to level off after 25°C.
However, spring temperatures for this Ohio population would have to drastically increase to have
substantial impacts on wood frogs (water temperatures for the source pond in this experiment aver¬
aged 13.7°C in early April; Dougherty et al., 2005).
In summary, we found that wood frogs are not strongly affected by NaCl concentrations
of 500 and 1000 mg/1, but they do suffer a reduction in survivorship when exposed to a warmer
temperature of 30.5°C in comparison to 25°C. There does not however appear to be a synergistic
effect of these stressors on wood frogs in this population, as evidenced by the lack of a significant
interaction between temperature and salinity.
Acknowledgments
We thank W. and L. Smith for assistance collecting egg masses. The experiment was
approved by the Denison University IACUC (protocol 10-003).
Literature Cited
Alvarez, D., and A.G. Nicieza,
2002. Effects of temperature and food quality on anuran larval growth and meta¬
morphosis. Funct. Ecol. 16: 640-648.
Castano, B., S. Miely, G.R. Smith, and J.E. Rettig.
2010. Interactive effects of food availability and temperature on wood frog ( Rana
sylvatica) tadpoles. Herpetol. J. 20; 209-21 1 .
Collins, S., and R. Russell.
2009. Toxicity of road salt to Nova Scotia amphibians. Environ. Poll. 157: 320-
324.
Dougherty, C.K., and G.R. Smith.
2006. Acute effects of road de-icers on the tadpoles of three anurans. Appl . Herpetol .
3: 87-93.
Dougherty, C.K., D.A. Vaala, and G.R. Smith.
2005. Within-pond oviposition site selection in two spring breeding amphibians (Am-
by stoma maculatum and Rana sylvatica). J. Freshwater Ecol. 20: 781-782.
Gosner, K.L.
1960. A simplified table for staging anuran embryos and larvae, with notes on
identification. Herpetologica 16: 183-190.
page 40
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Karraker, N.E.
2007. Are embryonic and larval green frogs ( Rana clamitans ) insensitive to road
deicing salt? Herpetol. Conserv. Biol. 2: 35-41 .
Karraker, N.. J. Gibbs, and J. Vonesh.
2008. Impacts of road deicing salt on the demography of vernal pool-breeding
amphibians. Ecol. Appl. 18: 724-734.
Kaushal, S.S., P.M. Groffman, G.E. Likens, K.T. Belt, W.P. StaCh, V.R. Kelly, L.E. Band, and G.T.
Fisher.
2005. Increased salinization of freshwater in the northeastern United States. Proc.
Nat. Acad. Sci. 102: 13517-13520.
Langhans, M., B. Peterson, A. Walker, G.R. Smith, and J.E. Rettig.
2009. Effects of salinity on survivorship of wood frog ( Rana sylvatica) tadpoles.
J. Freshwater Ecol. 24: 335-337.
Manis, M.L., and D.L. Claussen.
1986. Environmental and genetic influences on the thermal physiology of Rana
sylvatica. J. Therm. Biol. 11: 31-36.
Orizaola, G., and A. Laurila.
2009. Microgeographic variation in temperature-induced plasticity in an isolated
amphibian metapopulation. Evol. Ecol. 23: 979-991 .
Petranka, J.W., and E.J. Doyle.
2010. Effects of road salts on the composition of seasonal pond communities: can
the use of road salts enhance mosquito recruitment. Aquat. Ecol. 44: 155-
166.
Redmer, M., and S.E. Trauth.
2005. Rana sylvatica LeConte, 1825. In: Amphibian Declines: The Conservation
Status of United States Species, p. 590-595. Lannoo, M. Ed., University of
California Press, Berkeley.
Sanuy, D., N. Oromf, and A. Galofre.
2008. Effects of temperature on embryonic and larval development and growth
in the natterjack toad (Bufo calamita ) in a semi-arid zone. Anim. Biodiv.
Conserv. 31: 41-46.
Sanzo, D., and S. Hecnar.
2006. Effects of road de-icing salt (NaCl) on larval wood frogs {Rana sylvatica).
Environ. Poll. 140: 247-256
Jennifer H. Clemmer, Eliza Z. Miller, Laura Wolgamott, Geoffrey R. Smith*, and Jessica E. Rettig
Department of Biology, Denison University, Granville, OH 43023 USA
* Author for Correspondence: Phone: 1-740-587-6374, e-mail smithg@denison.edu
Received: 12 October 2011
Accepted: 1 November 201 1
Bulletin of the Maryland Herpetological Society
page 41
Volume 47 Numbers 1-4
January-December 2011
Body temperatures of Hyla arenicolor from
Sierra de Tepozotlan, Estado de Mexico, Mexico
Body temperature affects numerous aspects of locomotory and physiological performance
of Hyla treefrogs (Navas 1996b), In addition, climatic conditions, including temperature, are likely
to drive the differential distributions of some Hyla species (Otto et al. 2007). It is thus important
to gain a better understanding of the temperature relationships of Hyla frogs. However, there is
relatively little known about temperature relationships in the genus Hyla. Here we report on the
temperature relationships of Hyla arenicolor from Sierra de Tepozotlan, Estado de Mexico, Mexico
in an effort to expand the database of temperature relationships in treefrogs.
Materials and Methods
We conducted this study in Sierra de Tepozotlan (19° 42' 23.4" N, 99° 15' 17.6” W and
2300 m elevation), in Estado de Mexico, Mexico. Mean annual temperature and precipitation are
1 6°C and 650 mm, respectively. Plant species include Quercus crassipes , Q. microphylla , Q. riigosa,
Bouteloua curtipendula, B. gracilis , B. hirtusa, Lycurus phleoides, Piptochaetium fimbriatam, Ae-
gopogon cenchroides, Festuca sp., Pictochaetium fimbr latum, Bromus sp., Aristida sp., Oennetimi
clandestinum , Eragrostis sp. and Hilaria cenchroides , principally (Rzedowski 2006).
We captured frogs by hand. Once captured, we recorded snout vent length (SVL, to near¬
est 1 mm), body mass (to nearest 0.2 g, using a spring balance), and body (Tb; cloacal temperature,
to nearest 0.2°C). air (Ta; bulb in the shade, 3.0 cm over the substrate occupied by the lizard, to
nearest 0.2°C), and substrate temperature (Ts; bulb to the shade on the substratum occupied by the
small lizard, to nearest 0.2°C) using a quick-reading thermometer (Shultetheis, Miller and Weber
Inc., interval 0-50°C, 0.2 precision). We also recorded each frog's position with regard to solar in¬
solation as being completely exposed to sun, in shade, or in a sun/shade mosaic. Frogs that needed
a major effort to capture (> 1 min.) were excluded from temperature records. We used only one
observation for each frog.
Resuits and Discussion
Mean Tb was 25.11 ± 0.34 °C (N = 48). Mean Ta was 19.04 ± 0.32 °C (N = 48). Mean
Ts was 21 .69 ± 0.35 °C (N = 48). Mean Tb for our population of H. arenicolor is higher than that
observed in a population of H. arenicolor from Colorado (20.7°C; Snyder and Hammerson 1993).
Our observed mean Tb is within the range of Tbs observed in Hyla microcephala and H. ebraccata
from low elevations in Panama (Navas, 1996b), but is higher than in the high elevation H. lavialis
(Valdiviseo and Tamsitt 1974; Navas 1996a, b). Hyla regilla from southern California had Tbs
that ranged from 14.3 - 22.2 °C (Brattstrom and Warren 1955). Hyla cinerea from Louisiana had
nocturnal Tbs ranging from 19.1 - 27.7°C (Wygoda and Williams 1991).
Body temperature increased with Ta (N = 48, r2 = 0. 1 8, P = 0.0022; Tb = 16.26 + 0.46Ta).
Body temperature also increased with Ts (N = 48, N = 0.28, P = 0.0001 ; Tb = 14.02 + 0.51TS). The
Tbs of H. arenicolor from Colorado tended to be higher than Ta but lower than Ts (Snyder and
Hammerson 1993). The dependence of Tb on Ta has been found in other Hyla species (Valdivieso
and Tamsitt 1974; Wygoda and Williams 1991; Navas 1996a).
Body temperature increased with frog SVL, but only a small amount of variation in Tb
was explained by SVL (N = 48, r2 = 0.08, P = 0.046; Tb = 22.01 + 0.13SVL). Body temperature
was not related to frog mass (N = 46, r2 = 0.04, P = 0.16). Body temperature was not affected by
page 42 Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
SVL in H. labialis (Valdivieso and Tamsitt 1974).
January-December 2011
Most frogs were observed in sunny microhabitats (30; 62.5%), followed by mosaic mi¬
crohabitats (12; 25%). Few frogs were observed in shade (6; 12.5%). Microhabitat did not affect
Tb (Table 1 ; F2,45 = 1 .86. P = 0. 17), Ta (Table 1 ; F2,45 = 0.06, P = 0.94), or Ts (Table 1 ; F2>45 = 0.99,
p = 0.38). Snyder and Hammerson (1993) found all of the H. arenicolor they observed in June in
Colorado in full sun.
In conclusion, the temperature relationships we observed in H. arenicolor from Tepozot-
lan, Estado de Mexico, Mexico, are fairly similar to previous studies on the thermal ecology of H.
arenicolor and other species of Hyla.
Table 1. Mean body temperature (Tb), air temperature (Ta), and substrate temperature (Ts) of Hyla ar¬
enicolor found in sunny, sun/shade mosaic, and shaded microhabitats. Means are given ± 1 SE.
Sunny (N=30)
Tb(°C)
25.41 ±0.35 °C
Ta(°C)
18.96 ±0.41 °C
TS(°C)
22.06 ± 0.38 °C
Sun/Shade Mosaic (N=12) 25.22 ± 0.83 °C
19.16 ± 0.63 °C 21 .24 ± 0.83 °C
Shaded (N=6)
23.42 ± 1.19 °C
19.25 ±0.93 °C 20.07 ± 1.27 °C
Acknowledgments.
This study was supported by the projects: PAPIIT IN 221707, PAPCA 2008-2009;
2009-2010.
ldUmiLtiire_,Clited
Brattstrom, B.H., and J.W. Warren.
1 955 . Observations on the ecology and behavior of the Pacific treefrog , Hyla regilla.
Copeia 1955: 181-191.
Navas, C.A.
1 996a. Implications of microhabitat selection and patterns of activity on the thermal
ecology of high elevation neotropical anurans. Oecologia 108: 617-626.
1996b. Metabolic physiology, locomotor performance, and thermal niche breadth
in Neotropical anurans. Physiol. Zool. 69: 1481-1501 .
Otto, C.R.V., J.W. Snodgrass, D.C. Forester, J.C. Mitchell, and R.W. Miller.
2007. Climatic variation and the distribution of an amphibian polyploidy complex.
J. Anim. Ecol. 76: 1053-1061.
Rzedowski, J.
2006. La vegetacion de Mexico. Ira. Edicion digital. CONABIO, Mexico 504
pp.
Snyder, G.K., and G.A. Hammerson.
1 993 . Interrelationships between water economy and thermoregulation in the canyon
tree-frog Hyla arenicolor. J. Arid Environ. 25: 321-329.
Bulletin of the Maryland Herpetological Society
page 43
Volume 47 Numbers 1-4
January-December 2011
Valdivieso, D., and J.R. Tamsitt.
1974. Thermal relations of the neotropical frog Hyla labialis (Anura: Hylidae).
Life Sci. Occ. Papers, Royal Ontario Mus. 26: 1-10.
Wygoda, M.L., and A.A. Williams.
1991 . Body temperature in free-ranging green tree frogs {Hyla cinerea ): A com¬
parison with “typical” frogs. Herpetologica 47: 328-335.
Felipe Correa-Sdnchez1 , Geoffrey R. Smith2 A, Guillermo A. Woolrich-Piha 3,
and Julio A. Lemos-Espinal2
I Laboratorio de Herpetologia, Vivario , FES Iztacala UN AM, Av. De los Barrios # / Col.
Los Reyes Iztacala, Tlalnepantla, Estado de Mexico, Mexico. C. P. 54090.
2 Department of Biology, Denison University, Granville, Ohio 43023 USA.
2 Laboratorio de Ecologfa, Unidad de Biologfa, Tecnologia y Prototipos, FES Iztacala UN AM,
Av. De los Barrios # / Col. Los Reyes Iztacala, Tlalnepantla, Estado de Mexico, Mexico. C. P.
54090.
4 Author for Correspondence: smithg@denison.edu
Received:
Accepted:
6 May 2011
26 July 2011
page 44
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Clutch characteristics of the Pickerel Frog, Lithobates palustris
(LeConte, 1825), in Natchitoches, Louisiana
The Pickerel Frog, Lithobates palustris (LeConte, 1825) is an inhabitant of eastern North
America, including Louisana (Dundee and Rossman, 1989; Conant and Collins, 1991; Redmer,
2005). In northern Louisiana, breeding was reported during February-April and thought to occur
in the winter in southerly regions of the state (Dundee and Rossman, 1989). In Caddo Parish of
northern Louisiana, reproductive movements by females occurred during December- April (Hardy
and Raymond, 1991). In Louisiana, eggs are laid in firm globular masses of 2,000-3,000 eggs
(Dundee and Rossman, 1989). Here, we provide clutch characteristics of two Pickerel Frogs from
Natchitoches Parish, Louisiana. Two specimens were derived from the vertebrate collection of
Northwestern State University, Natchitoches, Louisiana. Female body size was measured in mm
snout-vent length (SVL). Clutch size was estimated by weighing a subset of mature ova. Means
are followed by ± 2 standard deviations.
The larger female (58.7 mm SVL), captured on 19 March 1969, contained an estimated
1 166.7 eggs. The smaller female (53.1 mm SVL), captured on 6 April 1971, contained and esti¬
mated 875 eggs.
Our data from Natchitoches did not conflict with the general range of adult females or
generally small clutches found in Arkansas (range= 960-2943 eggs) (Trauth et al., 1990), Missouri
(range= 704-2896 eggs) (Resetarits and Aldridge, 1988), and Pennsylvania (range= 850-2450 eggs)
(Meshaka et al ., 2010). Our findings do not conflict with an apparent stability in clutch characteristics
in this species (Meshaka et al., 2010).
Literature Cited
Conant, R. and J.T. Collins.
1 998. Reptiles and Amphibians of Eastern/Central North America. 3rd ed. Houghton
Mifflin Co. New York, New York. 616 pp.
Dundee, H.A. and D.A. Rossman.
1989. The Amphibians and Reptiles of Louisiana. Louisiana State University Press.
Baton rouge, Louisiana. 300 pp.
Hardy, L.M. and L.R. Raymond.
1991. Observations on the activity of the pickerel frog, Rana palustris (Anura:
Ranidae) in northern Louisiana. Journal of Herpetology 25:2:220-222.
Meshaka, W.E., Jr., N. Edwards, and PR. Delis.
2010. Seasonal Activity, Reproductive Cycles, and Growth of the Pickerel Frog,
Lithobates palustris (LeConte, 1825), From Pennsylvania. Herpetological
Bulletin, In review.
Redmer, M.
2005. Rana palustris LeConte, 1825: Pickerel Frog. Pp. 568-570 In M. Lannoo,
editor, Status and Conservation of North American Amphibians. University
of California Press. Berkeley, California. 1094 pp.
Bulletin of the Maryland Herpetological Society
page 45
Volume 47 Numbers 1-4
Resetarits, W.J.. Jr. and R.D. Aldridge,
January-December 2011
1988. Reproductive biology of a cave-assoicated population of the frog Ranci
palustris. Canadian Journal of Zoology 66:329-333.
Trauth, S.E., R.L. Cox, B.P. Butterfield, D.A. Saugey, and W.E. Meshaka.
1990. Reproductive phenophases and clutch characteristics of selected Arkansas
amphibians. Proceedings of the Arkansas Academy of Science 44: 107-1 13.
Walter E. Meshaka , Jr., Section of Zoology and Botany, State Museum of Pennsylvania, 300
North Street, Harrisburg, PA 17120, U.S.A. wmeshaka@state.pa.us [author for correspondence] .
Samuel D. Marshall, Department of Biology, Northwestern State University, Natchitoches, LA
71497, U.S.A.
Received: 23 March 201 1
Accepted: 17 May 201 1
page 46
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Distribution of Tadpoles (Hyla arenicolor ) in the Pools
Associated with the Rio Salado, Puebla, Mexico
One of the goals of studying the ecology of anurans is to understand why it’s distributed
in some sites and not in others. It has been documented that factors such as PH , temperature, pho¬
toperiod, dissolved oxygen, and salinity, among others, are involved in the distribution of tadpoles
(Welch and MacMahon, 2005; Girish and Krishnamurthy, 2009; Woolrich-Pina et al., 2010).
The Rio Salado is characterized by a high level of salinity present in the low basin ( 1 .0-
6.0 ppt) due to the erosion of carbonated sediment from the medium and high basin as well as for
the production of salt (Woolrich-Pina, 2010). This might influence the distribution of the anurans
that inhabit the different pools associated with the river. Hyla arenicolor is one of four species of
anurans that are distributed along the Rio Salado, in the Valle de Zapotitlan Salinas, Puebla. Mexico.
Here we report which are the factors that influence the distribution of H. arenicolor (tadpoles) in
the Rio Salado.
Materials and Methods.
The study was realized in San Juan Raya, municipality of Zapotitlan Salinas Valley (18°
18’ N, 97° 37' W and 1730 m elevation), in Puebla, Mexico. Mean annual temperature and precipi¬
tation are 21°C and 400 mm, respectively. Plant species include some cacti ( Nebonxbamia tetetzo ,
Cephalocereus spp.), mesquite trees ( Prosopis laevigata ), and pata de elefante trees ( Beucarnea
gracilis), principally (Rzedowski 2006).
We conducted surveys along a 1 km segment of the Rio Salado monthly from March to
June 2010 to characterize conditions in the river and determine the distribution of tadpoles of H.
arenicolor. The conditions characterized were: length, width and depth (cm), salinity (ppt), and
dissolved oxygen (mg/L-i) of each pond. Salinity, and dissolved oxygen were measured using a
YSI Model 85 Handheld DO/ conductivity meter.
We used a multivariate analysis of variance (MANOVA) to compare the physical and
chemical parameters between pools with and without tadpoles among months. A significant
MANOVA was followed by unifactorial nested ANOVAS to examine each variable in detail.
Results.
MANOVA found significant differences in the pools with and without tadpoles (Wilks’
X = 0.008, F28 , 1 32 = 25.13, P < 0.01). Tadpoles were found in pools deeper (Fp52 = 23.8. P < 0.01),
wider (Fp.52 = 5.73, P < 0.01), longer (Fi^ = 5.68, P < 0.01), with higher dissolved oxygen (DO)
levels (Fj 52 = 40.3, P < 0.01) and lower salinity (Fp52 = 348.7, P < 0.01) than pools without tad¬
poles (see table 1).
Discussion.
Hylid tadpoles were observed in pools with low salinity. This has been observed in other
anuran species, because it generally does not frequent environments with high salt concentrations
(Davenport and Huat, 1997; Smith et al., 2007; Wells 2007). However, it has been observed that
salinity did not affect the distribution of Buergeria japonica tadpoles, the abundance of Rhinella
marina increased with salinity, and Fejervarya cancrivora tolerates it in very high concentrations
(Gordon et al., 1961; Haramura, 2007; Rfos-Lopez, 2008).
Bulletin of the Maryland Herpetological Society
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Volume 47 Numbers 1-4
January-December 2011
We also found tadpoles in pools with higher DO levels. This is consistent with other spe¬
cies (e.g. Incillius \Ollotis ] occidentalism Rana pipiens and Anaxyrus terrestris ; Noland and Ultsch,
1981; Woolrich-Pina et al . , 20 1 0) . Dissolved oxygen can be related to species richness and predation
on tadpoles (Ultsch et al., 1999; Peltzer and Lajmanovich, 2004).
Tadpoles were distributed in longer, wider and deeper pools. A pool with a greater volume
has a lower probability of dessication, increasing the time for larval development. Premature pool
drying is often a major cause of mortality for the larvae of many species (Beebee, 1996).
Due to the importance of water chemistry in the distribution of H. arenicolor tadpoles, it is
important to consider the potential effect of salt factories on water quality in the river. Salt factories
(“salineras”) divert water from the Rio Salado to harvest the salt by evaporation. Thus it is possible
that the salineras may impact the habitat of native fauna, including H. arenicolor.
Table 1. Mean values and interval of the chemicals and physicals parameters present in the
ponds.
Pond
O rng/L-1
Salinity ppt
Length (m)
Width (m)
Depth (in)
With tadpoles
4.7 ±0.4
(1.2 -2.8)
4.1 ±0.7
(0.8 -5.9)
6.4 ± 1.6
(1.3-15)
1.1 ±0.6
(0.43-3.2)
0.26 ± 0.05
(0.25-1)
Without tadpoles
2.3 ±0.7
(3.3 -6.5)
0.9 ±0.08
(0.2 -0.9)
3.2 ±0.9
(0.8 -4.7)
2.5 ±0.6
(0.84-6.4)
0.55 ±0.08
(0.08-0.42)
Acknowledgments.
This study was supported by the projects: PAP1IT IN 221707, and PAPCA 2008-2009;
PAPCA 2009-2010.
Literature Cited.
Beebee T. J.
1996. Ecology and conservation of amphibians. Chapman & Hall Press. UK. 214
pp.
Davenport J., and K. K. Huat.
1997. Salinity tolerance and preference in the frog Rana rugulosa (Wiegmann).
Herpetological Journal 7 : 114-115.
Girish K., and S. V. B. Krishnamurthy.
2009. Distribution of tadpoles of largewrinkled frog Nyctibatrachus major in
central Western Ghats: influence of habitat variables. Acta Herpetologica 4
(2): 153-160.
Gordon M. S., K. Schmidt-Nielsen, and H. M. Kelly.
1961. Osmotic regulation in the crab-eating frog (Rana cancrivora). Journal of
Experimental Biology 38: 659-678.
page 48
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
HaramuraT.
2007. Microhabitat selection by tadpoles of Buergeria japonica inhabiting the
coastal area. Journal of Ethology 25: 3-7.
Noland R., and G. R. Ultsch.
1981. The roles of temperature and dissolved oxygen in microhabitat selection by
the tadpoles of a frog (. Rana pipiens ) and a toad {Bnfo terrestris). Copeia
1981: 645-652.
Peltzer P.M., and R. C. Lajmanovich.
2004. Anuran tadpole assemblages in riparian areas of the Middle Parana River,
Argentina. Biodiversity and Conservation 13: 1833-1842.
Rios-Lopez N .
2008. Effects of increased salinity on tadpoles of two anurans from a Caribbean
coastal wetland in relation to their natural abundance. Amphibia-Reptilia 29:
7-18.
Rzedowski J.
2006. Vegetacion de Mexico, la edicion digital. CONABIO. D. F. Mexico. 504
pp.
Smith M. J., E. S. G Schreiber, M. P. Scroggie, M. Kohout, K. Ough, J. Potts, R. Lennie, D. Turn-
bull, C. Jin, and T. Clancy.
2007. Associations between anuran tadpoles and salinity in a landscape mosaic of
wetlands impacted by secondary salinisation. Freshwater Biology 52: 75-
84.
Ultsch G. R.. D. F. Bradford, and J. Freda.
1999. Physiology: Coping with the Environment. In R.W. McDiarmid and R.
Altig (eds). Tadpoles: The Biology of Anuran Larvae. Univ. Chicago Press,
Chicago, Illinois. USA. pp. 189-214.
Welch N. E., and J. A. Macmahon.
2005. Identifying habitat variables important to the rare Columbia spotted frog
in Utah (USA): an information-theoretic approach. Conservation Biology
19:473-481 .
Wells K.D.
2007. The ecology and behavior of amphibians. University of Chicago Press.
Chicago, Ill ionois. USA. 1 148 pp.
Woolrich-Pina G. A.
2010 . Caracterizacion hidrologica del Valle de Zapotitlan Salinas (Puebla) y su
influencia en la distribucion de los anfibios: aspectos geOgraficos, ecologicos
y de conservation. Tesis doctoral. Facultad de Filosoffa y Letras, UN AM.
138 pp.
Bulletin of the Maryland Herpetological Society
page 49
Volume 47 Numbers 1-4 January-December 2011
Woolrich-Pina G. A., G. R. Smith, L. Oliver-Lopez, M. Barbosa Morales, and J. A. Lemos-
Espinal .
2010. Distribution of tadpoles of Ollotis occidentalis (Amphibia: Anura: Bufonidae)
along the Rio Salado, Puebla, Mexico. Acta Herpetologica 5 (2): 151-160.
Guillermo A. Woolrich-Pina1 2 A , Julio A. Lemos-Espinal1 , Geoffrey R. Smith3,
Raymundo Montoya -Ayala4 and Luis Oliver-Lopez1
1 La bo rat or io de Ecologfa, Unidad de Biologia, Tecnologfa y Prototipos, FES Iztacala UN AM,
Av. De los Barrios # I Col. Los Reyes Iztacala , Tlalnepantla, Estado de Mexico, Mexico. C. P.
54090de Herpetologfa, Vivario, FES Iztacala UN AM, Av. De los Barrios # I Col. Los Reyes
Iztacala, Tlalnepantla, Estado de Mexico, Mexico. C. P. 54090.
2 Laboratorio de Geobiologfa y Paleontologfa, ESI A Ticoman “ Ciencias de la Tierra” IPN. Av.
Ticoman # 600, Col. San Jose Ticoman, Del. Gustavo A. Madero, Mexico D. F.C. P. 07340.
3 Department of Biology, Denison University, Granville, Ohio 43023 USA.
4 Laboratorio de Computo, Unidad de Biologia, Tecnologfa y Prototipos, FES Iztacala UNAM,
Av. De los Barrios # I Col. Los Reyes Iztacala, Tlalnepantla, Estado de Mexico, Mexico. C. P.
54090de Herpetologfa , Vivario, FES Iztacala UNAM, Av. De los Barrios # I Col. Los Reyes
Iztacala, Tlalnepantla , Estado de Mexico, Mexico. C. P. 54090.
3 Author for Correspondence: woolrichg@unam.mx
Received: 14 July 2011
Accepted: 23 August 20 1 1
page 50
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Mississippi Map Turtle, Graptemys pseudogeographica
kohnii, Documented in Frederick County Maryland
A non-native species of turtle was observed and photographed in the Monocacy River
at Links Bridge Road Frederick County Maryland (lat. 39.534046° Ion. -77.353774°) on 29 Aug
2010 while conducting field research for the Maryland Amphibian and Reptile Atlas (MARA).
The low resolution photograph showed the specimen to be one of the Map Turtles. To confirm
species identification I returned to the same location the following day with a telephoto camera.
I observed and photographed two Graptemys pseudogeographica kohnii , note the characteristic
crescent shape mark behind the eye (Figures 1 and 2). Further research is needed to determine if
this report represent a viable colony.
The indigenous range for the Mississippi Map Turtle, a sub species of the False Map
Turtle, is the Mississippi River basin from western Tennessee into Missouri and Nebraska and south
to the Gulf of Mexico in Texas, Louisiana, and Mississippi. Graptemys pseudogeographica kohnii
were previously documented in Calvert County Maryland (Schwartz and Dutcher, 1960) and near
Washington D.C. in the Middle Potomac- Anacostia-Occoquan area (Mitchell, 1994), however this
report represent the first for Frederick County Maryland.
Figure 1. Mississippi Map Turtle, Graptemys pseudogeographica kohnii
Bulletin of the Maryland Herpetological Society
page 51
Volume 47 Numbers 1-4 January-December 2011
Figure 2. Mississippi Map Turtle, Grciptemys pseudogeographica kolmii.
Literature Cited.
Ernst, Carl H.. Jeffrey E. Lovich, and Roger W. Barbour.
1994. Turtles of the United States and Canada. Smithsonian Institution Press,
Washington D.C.
Mitchell, Joseph C.
1994. The Reptiles of Virginia. Smithsonian Institution Press, Washington D.C.
Schwartz, Frank J. and Benjamin L. Dutcher.
1960. A Record of the Mississippi Map Turtle, Graptemys kohni , in Maryland.
Chesapeake Science. Volume 2, Numbers 1-2: 100-101.
Wayne G Hildebrand, Maryland Calling Amphibian Coordinator, North American Amphibian
Monitoring Program and Frederick County Coordinator of the Maryland Amphibian and Reptile
Atlas Keymar Maryland 21757, wayne.mdfrog@comcast.net
Received: 13 March 2011
Accepted: 12 June 2011
page 52
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Reproduction in Clark’s Spiny Lizard, Sceloporus clarkii
(Squamata: Phrynosomatidae) From Sinaloa, Mexico
Abstract.
A histological examination of gonads from Clark’s spiny lizard, Sceloporus clarkii , from
Sinaloa, Mexico revealed an extended period of spermiogenesis (sperm formation) that extended from
spring into late summer. Recrudescence (renewal of germinal epithelium in the seminiferous tubules
for the next period of spermiogenesis) began in winter. Yolk deposition (enlarged follicles > 5 mm)
was underway in June. Ovarian activity continued into August. Histological evidence indicates that
S. clarkii produces multiple clutches in the same year. The mean clutch size for 1 8 gravid females
was 9.56 ± 2.60, range = 7-18. Females of S. clarkii from Sinaloa mature at a smaller size, produce
smaller clutches and produce clutches later in the year than do Arizona populations.
Introduction.
Clark’s spiny lizard, Sceloporus clarkii Baird and Girard, 1852 ranges from central Arizona and
southwest New Mexico, south to Jalisco, Mexico from sea level to ca. 1830 m; (Stebbins, 2003).
It tends to prefer oak-pine woodlands, tropical deciduous forests and subtropical thorn forests of
lower mountain slopes (Stebbins, 2003). Anecdotal accounts of S. clarkii reproduction appeared
in Kauffeld (1943), Stebbins (1954, 2003), Fitch (1970, 1985), Hulse (1973), Parker (1973), Vitt
(1977), Behler and King ( 1979), Degenhardt et al. ( 1996), Brennan and Holycross (2006), Schwable
and Rosen (2009). The most detailed study on the reproduction of S. clarkii was by Tinkle and
Dunham (1986) on a population from central Arizona. Fitch (1985) reported larger clutch sizes from
northern (Arizona) versus southern (Mexico) populations of S. clarkii. The purpose of my study
is to compare aspects of the reproductive biology of S. clarkii from central Arizona (Tinkle and
Dunham, 1986) with that of a conspecific population in Sinaloa, Mexico approximately 1200 km
southward. Information on timing of sperm production, clutch size and body (SVL), size at maturity
provides life history data that may be useful in elucidating phylogenetic affinities.
Methods.
A sample of 79 adult S. clarkii , consisting of 43 males (mean SVL = 93.4 mm ± 12.7 SD,
range = 63-124 mm) and 36 females (mean SVL = 84.8 mm ± 9.9 mm, range = 71-111 mm) and
an additional six sub-adults (mean SVL = 63.0 mm ± 6.5 SD, range = 52-68 mm), all collected
during the period 1933-1979 from Sinaloa, Mexico was examined (Appendix).
For histological examination, the left testis was removed from males and the left ovary
was removed from females. Enlarged follicles (> 5 mm length) or oviductal eggs were counted {in
situ). Tissues were embedded in paraffin and cut into sections of 5 pm.
Slides were stained with Harris’ hematoxylin followed by eosin counterstain (Presnell and
Schreibman, 1997). The slides of testes were examined to determine the stage of the spermatogenic
cycle while the slides of ovaries were examined for the presence of yolk deposition or corpora lutea.
Histology slides were deposited in LACM. An unpaired t- test was used to compare S. clarkii male
and female body sizes (SVL)s. The relationship between female body size (SVL) and clutch size
was investigated by linear regression analysis. Statistical tests were performed using Instat (vers.
3.0b, Graphpad Software, San Diego, CA).
Bulletin of the Maryland Herpetoiogical Society
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Volume 47 Numbers 1-4
Results.
January-December 2011
The S. clarkii males were significantly larger than the females (unpaired /-test, df= 78, t
= 3.3 1 , P = 0.001). Monthly stages in the testicular cycle are in Table 1 . Three stages were observed
in the testicular cycle: (1) regressed in which the seminiferous tubules contain mainly spermato¬
gonia interspersed with Sertoli cells; (2) recrudescence in which proliferation of germ cells for the
next period of sperm formation has commenced. Primary spermatocytes and occasional secondary
spermatocytes predominate. In late recrudescence (April) some spermatids are noted; (3) spermio-
genesis in which the lumina of the seminiferous tubules are lined by clusters of sperm or clusters of
metamorphosing spermatids. Recrudescence was noted in winter and early spring (Table 1). Sperm
formation (spermiogenesis) began in May and continued into August. Regressed testes appeared
in August, September and December (Table 1). The smallest reproductively active male measured
63 mm SVL (LACM 6623) and was from June. One slightly smaller male, 58 mm SVL (LACM
8631) from April with a regressed testis was considered a subadult.
Monthly stages in the ovarian cycle of S. clarkii are listed in Table 2. Five stages were
observed: (1) quiescent, in which there is no yolk deposition; (2) early yolk deposition, in which
vitellogenic granules are accumulating within the follicles; (3) enlarged follicles > 5 mm; (4) ovi-
ductal eggs; and (5) corpora lutea (previous clutch) and concomitant yolk deposition for a subse¬
quent clutch. Reproductively active females were present in June, July and August. Because spring
samples were lacking, it was not possible to determine when females commenced reproductive
activity. One female from 2 August (LACM 6633) contained corpora lutea from a previous clutch
and concomitant yolk deposition for a subsequent clutch while a second female (LACM 6634)
from 3 August contained oviductal eggs with concomitant yolk deposition for a subsequent clutch
both indicating that S. clarkii from Sinaloa can produce multiple clutches in the same reproductive
season (Table 2). The mean clutch size for the 18 gravid females was 9.56 ± 2.60, range = 7-18.
The relationship between female SVL and clutch size was not significant (n = 18, P = 0.0744).
The smallest reproductively active female S. clarkii (LACM 6647) collected in August contained
8 enlarged follicles (> 5 mm) and measured 73 mm. Three smaller females with quiescent ovaries
collected in April (SVL = 66-68 mm) were considered to be subadults.
Discussion.
Males of S. clarkii are similar to other North American lizards that exhibit spring-summer
spermiogenesis (Goldberg 1974, 1975, 1976, 1977, 1983). However, they differ in the extended
length of sperm production, in Sinaloa, which continues into August.
Table 1. Monthly stages in
the testicular cycle of 43 Sceloporus clarkii from Sinaloa, Mexico.
Month
N
Regressed
Recrudescent
Spermiogenesis
January
1
0
1
0
March
1
0
1
0
April
3
0
3
0
May
1
0
0
1
June
8
0
0
8
July
13
0
0
13
August
14
5
0
9
September
1
1
0
0
December
1
1
0
0
page 54 Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
January-December 2011
Fitch ( 1970) reported one of four S. clarkii females collected in November from Mexico
(locality not specified) in a series from Chihuahua, Durango and Sinaloa as gravid. Sixty-seven
percent (n = 15) of August females from Sinaloa were reproductively active (Table 2). Sceloporus
clarkii females in Sinaloa mature at 73 mm SVL as was also reported by Fitch (1970). In contrast,
Tinkle and Dunham ( 1986), reported that females from central Arizona, finished reproducing in late
July; one female had oviductal eggs on 1 August. In S. clarkii from central Arizona females mature
at 90 mm SVL (Tinkle and Dunham 1986), a larger size than in Sinaloa. Clutch sizes of S. clarkii
from Mexico were smaller than those produced by females in Arizona (Table 3).
In conclusion, my data indicate variation in the reproductive cycles of S. clarkii from
central Arizona (Tinkle and Dunham 1986) versus Sinaloa, Mexico. Females from Sinaloa mature
at a smaller size, produce smaller clutches and produce clutches later in the year than do Arizona
populations.
Table 2. Monthly stages in the ovarian cycle of 36 Sceloporus clarkii from Sinaloa, Mexico.
Month n
Quiescent
Early yolk
deposition
Enlarged follicles
> 5mm
Oviductal
eggs
Corpora lutea
and yolk deposition
June 6
3
0
1*
2
0
July 12
0
4
2
6**
0
August 15
5
0
5
1
September 2
2
0
0
0
0
October 1
1
0
0
0
0
^Follicles were damaged and could not be counted; **One group of oviductal eggs were damaged and could not be
counted; ***One female contained oviductal eggs and concomitant yolk deposition for a subsequent clutch.
Table 3. Mean clutch sizes for Sceloporus clarkii from different parts of its range.
Location
n
Mean Clutch Size
Range
Source
Mexico (Chihuahua,
Durango, Sinaloa)
6
8.0
1-10
Fitch, 1985
Sinaloa
18
9.6
7-18
This paper
Central Arizona
32
19.6
7-28
Tinkle and Dunham, 1986
Southern Arizona
17
15.2
8-24
Fitch, 1985
Acknowledgment.
1 thank Christine Thacker (LACM) for permission to examine S. clarkii.
Bulletin of the Maryland Herpetological Society
page 55
Volume 47 Numbers 1-4
January-December 2011
Literature Cited.
Behler, J. L.and F. W. King.
1979. The Audubon Society Field Guide to North American Reptiles & Amphib¬
ians. Alfred P. Knopf, New York. 719 pp.
Brennan, T. C. and A. T. Holycross.
2006. A Field Guide to Amphibians and Reptiles in Arizona. Arizona Game & Fish
Department, Phoenix. 150 pp.
Degenhardt, W. G., C. W. Painter, and A. H. Price
1996.
Amphibians & Reptiles of New Mexico. University of New Mexico Press.
Albuquerque. 431 pp.
Fitch. H.S.
1970.
Reproductive cycles in lizards and snakes. University of Kansas Museum
of Natural History, Miscellaneous Publication 51:1-247.
Fitch, H.S.
1985.
Variation in clutch and litter size in New World reptiles. University of Kansas
Museum Natural History, Miscellaneous Publications No. 76: 1-76.
Goldberg, S.R.
1 974. Reproduction in mountain and lowland populations of the lizard Sceloporus
occidentalis . Copeia 1974:176-182.
Goldberg, S. R.
1975.
Reproduction in the sagebrush lizard, Sceloporus graciosus. American Mid¬
land Naturalist 93:177-187.
Goldberg, S.R.
1 976. Reproduction in a mountain population of the coastal whiptail lizard, Cnemi-
dophorns tigris multiscutatus . Copeia 1976:260-266.
Goldberg, S.R.
1977.
Reproduction in a mountain population of the side-blotched lizard, Uta stans-
buriana (Reptilia, Lacertilia, Iguanidae). Journal of Herpetology 1 1 :3 1 -35 .
Goldberg, S. R.
1983.
Reproduction of the coast horned lizard, Phrynosoma coronation, in southern
California. Southwestern Naturalist 28:478-479.
Hulse, A. C.
1973.
Herpetofauna of the Fort Apache Indian Reservation, east central Arizona.
Journal of Herpetetology. 7:275-282.
Kauffeld, C. F.
1943.
Field notes on some Arizona reptiles and amphibians. American Midland
Naturalist 29:342-359.
Parker, W. S .
1973.
Notes on reproduction of some lizards from Arizona, New Mexico, Texas
and Utah. Herpetologica 29:258-264.
page 56
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
Presnell, J. K. and M. P. Scbreibman.
1997. Humason’s Animal Tissue Techniques. 5* Edit. The Johns Hopkins Press,
Baltimore, 572 pp.
Schwalbe, C. R. and P. C. Rosen.
2009.
Clark’s spiny lizard, Sceloporus clarkii Baird and Girard, 1852. Pp 206-209
in: Jones, L. L.C. & R. E. Lovich.(eds). Lizards of the American Southwest.
A Photographic Guide. Rio Nuevo Publishers, Tucson. 567 pp.
Stebbins, R. C.
1954.
Amphibians and Reptiles of Western North America. McGraw-Hill Book
Company, Boston. 536 pp.
Stebbins, R. C.
2003.
A Field Guide to Western Reptiles and Amphibians, 3rd Edit. Houghton-Mif-
flin Company, Boston. 533 pp.
Tinkle, D. W. and A. E. Dunham
1986.
Comparative life histories of two syntopic sceloporine lizards. Copeia 1986: 1 -
18.
Vitt, L. J.
1977.
Observations on clutch and egg size and evidence for multiple clutches in
some lizards of southwestern United States. Herpetologica 33:333-338.
Appendix
Sceloporus clarkii from Sinaloa, Mexico examined from the Natural History Museum of
Los Angeles County (LACM), Los Angeles, California: 6620-6626, 6628-6641 , 6644, 6645,6647-
6657,7303,8626, 8628,8631-8636, 17396, 17397, 17400, 37618,50992,51012-51014,65182,
74296, 92952, 95628-95635, 95637-95650, 95652-95655, 95953, 121323, 133272-133274.
Stephen R. Goldberg , Biology Department, Whittier College, PO Box 634, Whittier, CA 90608,
sgoldberg@whittier.edu
Received: 1 3 December 20 1 0
Accepted: 30 December 20 1 0
Bulletin of the Maryland Herpetological Society
page 57
Volume 47 Numbers 1-4 January-December 2011
Harassment/Predation of
Maryland Snakes by Bird Species
Elsewhere, there are many accounts of predation on snakes by birds. Eagles, Falcons,
Hawks.... all birds of prey are well known snake eaters. Ravens, Crows, Magpies (all the corvid
types) and Kookies all eat small snakes. Egrets, Herons and Storks are also known snake eaters.
A quick check online, indicated that Wikipedia, the Free Encyclopedia (201 1) listed Red Tailed
Hawks, Red Shouldered Hawks, Secretary Birds, Shrikes, Stellar’s Sea Eagle, Bald Eagle, Osprey,
Blue Heron, American Egret, Cattle Egret, Green Heron, Sandhill Crane, Limpkin and Wood Stork
as snake eaters.
Shine et al.(2000, 2001 ) noted that in Manitoba, during the spring mating season, intense
predation primarily by crows ( Corvus brachyrhynchos) on mainly small snakes. They stated that
“Crows generally removed the snake’s liver and left the carcass....”.
Seeing birds preying on DOR snakes is quite common, while observing the attacks on
living snakes is probably relatively more common than observations would indicate.
On 1 2 April 2005 I observed an Eastern Crow ( Corvus brachyrhynchos brachyrhynchos)
feeding on the carcass of a DOR Scotophis alleghaniensis on Dicus Mill Road, 0.2 mi South Pyles
Lane, Anne Arundel County, Maryland, something seen very commonly along all roads.
Not as common, is the predation on snakes by birds. On 17 September 2004 I observed
a group of five crows (< Corvus brachyrhynchos brachyrhynchos) deliberately attacking a six foot
Scotophis alleghaniens on Grover Road at Brightview Drive, Anne Arundel County, Maryland..
This snake was thin and appeared debilitated. It however kept backing up and finally was able to
disappear under the vegetation along the side of the road. The crows kept grabbing the tail trying
to pull in back on the road, but were unsuccessful.
A US Postal Service employee, John Dirks relayed an account from 1 :30 PM on 17 May
2011. On walking up the walk way to a house at 136 Drexel Drive, Millersville, Anne Arundel
County, Maryland, he encountered two Eastern Crows ( Corvus brachyrhynchos brachyrhynchos)
harassing a 4 foot Scotophis alleghaniensis. The crows seemed persistent and were still pursuing
the snake when he left. He said the snake seemed to be in good health.
Another US Postal Service employee, Carl Carlson, relayed two observations made on
consecutive days. He has tentatively identified the hawks involved as Red-Shouldered Hawks ( Buteo
lineatus) and the black snakes as Scotophis alleghaniensis. Carl is a cigar smoker, and pauses to
enjoy both nature and his cigar! On 18 March 2010 at 12:00 Noon, he observed a large hawk, car¬
rying a black snake, fly to it’s nest at the top of a large tree off Zeman Road, just off Obrecht Road,
Anne Arundel County, Maryland. On 19 March 2010, at 12:30 PM, he observed a large hawk,
carrying a black snake, fly up on to the roof of a house at 6 Forham Court, off West Pasadena Road,
Anne Arundel County, Maryland, where it proceeded to devour the snake. These snakes were in
the 4 foot size range. This is perhaps a danger faced by many snakes emerging from hibernation
enjoying the rays of the sun out in the open, and during the spring matting season as mentioned
above (Shine, (2000, 2001).
And now to the most interesting account concerning a Cat Bird ( Dumetella carolinen-
sis). Boris Stegmar told me of an observation he made on 17 August 2011. The observation was
made in the early afternoon at 1152 River Bay Road, Annapolis, Maryland. He watched as a Cat
Bird repeatedly harassed a three foot Scotophis alleghaniensis. The snake kept retreating while
page 58
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4 January-December 2011
the Cat Bird followed in pursuit pecking the snake’s tail. This went on for about five minutes until
the snake managed to escape. I would imagine that Cat Birds are normal prey items for Scotophis
alleghaniensis so this appears to be abnormal behavior, or perhaps it had a nest that was threaten
by the snake.
Literatu,re_Cit_e_4
Shine, Richard, M. P. LeMaster, I. T. Moore, M. M. Olsson, and R. T. Mason.
2001 . Bumpus in the snake den: effects of sex, size, and body condition on mortality
of Red-Sided Garter Snakes. Evolution 55(3):598-604.
_ , M. M. Olsson, M. P. LeMaster, I. T. Moore, and R. T. Mason.
2000. Effects of sex, body size, temperature, and location on the antipredator tactics
of free-ranging garter snakes ( Thamnophis sirtalis, Colubridae). Behavioral
Ecology 11(3):239=245.
Wikipedia, the Free Encyclopedia
2002. Snake Eating Birds .http://wikipedia.org/wiki/Ophiophagy.
Herbert S. Harris , Jr., Department of Herpetology, Natural History Society of Maryland, 6908
Belair Road, P.O. Box 18750, Baltimore, Maryland 21206, (hsharris@juno.com).
Bulletin of the Maryland Herpetological Society
page 59
Volume 47 Numbers 1-4
News and Notes:
January-December 2011
Call for Papers
This is the first time in forty six years, as Editor of the Bulletin of the Maryland Herpe-
tological Society, that I did not receive enough material to put out four Numbers to this Volume.
This is a plea to all of you for help in the coming year. The Bulletin has been a part of the NHSM’s
Department of Herpetology and we really would like to see it continue. Thank you for your past
support and please answer this call for additional support. Thank you. The Editor.
page 60
Bulletin of the Maryland Herpetological Society
Volume 47 Numbers 1-4
News and Notes:
January-December 2011
’
Society Publication
Back issues of the Bulletin of the Maryland Herpetological Society, where
available, may be obtained by writing the Executive Editor. A list of available
issues will be sent upon request. Individual numbers in stock are $5.00 each,
unless otherwise noted.
The Society also publishes a Newsletter on a somewhat irregular basis.
These are distributed to the membership free of charge. Also published are
Maryland Herpetofauna Leaflets and these are available at $. 25/page.
Information for Authors
All correspondence should be addressed to the Executive Editor. Manu¬
scripts being submitted for publication should be typewritten (double spaced)
on good quality 8 1/2 by 11 inch paper with adequate margins. Submit original
and first carbon, retaining the second carbon. If entered on a word processor,
also submit diskette and note word processor and operating system used. Indi¬
cate where illustrations or photographs are to appear in text. Cite all literature
used at end in alphabetical order by author.
Major papers are those over five pages (double spaced, elite type) and
must include an abstract. The authors name should be centered under the title,
and the address is to follow the Literature Cited. Minor papers are those pa¬
pers with fewer than five pages. Author’s name is to be placed at end of paper
(see recent issue). For additional information see Style Manual for Biological
Journals (1964), American Institute of Biological Sciences, 3900 Wisconsin
Avenue, N.W., Washington, D.C. 20016.
Reprints are available at $.07 a page and should be ordered when manu¬
scripts are submitted or when proofs are returned. Minimum order is 100 re¬
prints. Either edited manuscript or proof will be returned to author for approval
or correction. The author will be responsible for all corrections to proof, and
must return proof preferably within seven days.
The Maryland Herpetological Society
The Natural History Society of Maryland
P.O. Box 18750
6908 Belair Road
Baltimore, MD 21206
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