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\" Gomi. United States
is, *\ Department of
{5 3) Agriculture

Forest Service

Pacific Northwest
Forest and Range
Experiment Station

PNW-421

March 1985
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Research Note

_ Abstract

A Portable Vacuum
for Collecting Arthropods
From Drop Cloths

H.G. Paul and R.R. Mason

A hand-he!d vacuum modified for collecting insects and spiders In
the field is described. The vacuum with battery is mounted on a
lightweight pack-frame and is portable and versatile. It is
especially useful for collecting arthropods that are dislodged
from foliage samples and drop onto cloths.

Keywords: Field equipment, sampling methods, insect populations.

Forest defoliators are often sampled by beating foliage over a
drop cloth and counting the dislodged larvae that fall on the
cloth. Foliage beating also affords an opportunity to examine
associated arthropods that drop off the branch at the same time.
These are usually other Insects and spiders, many of which may be
predators of small! defoliating larvae. Because a variety of
species and stages may be involved, these associates are best
collected and examined later in the laboratory. Collection has
to be quick, however, lest some individuals escape by flying or
running off the cloth. A small portable vacuum modified for
field use Is an excellent tool for rapidly collecting selected
specimens from a drop cloth.

The vacuum Is a hand-held Black and Decker Car-Vac! powered by a
3-ampere, 12-volt electric motor. The suction opening In the
front cover is made smaller by plugging the opening with a fitted
wooden block and plaster of paris through which a 1/2-inch
(12.7-mm) hole is bored (fig. 1A). Suction fs through a 3/8-inch

The use of trade names is for the information and convenience of
the reader only. Such use does not constitute an official
endorsement or approval by the U.S. Department of Agriculture of
any product or service to the exclusion of others which may be
suitable.

H.G. PAUL is forestry technician and R.R. MASON is research
entomologist, Forestry and Range Sciences Laboratory, Route 2,
Box 2315, La Grande, Oregon 97850.

BOX NAIL HOLDS
PLYWOOD & PLASTER
TOGETHER (WHILE
PLASTER IS DRYING)

INSIDE. SILICONE

DIAMETER | \CAULKING
POLYURETHANE

TUBING

|
|
|
|
v

1/2” DIAMETER |
HOLE IN |

3/8”
OUTSIDE

PLYWOOD DIAMETER
3/8” 3/4” ROUND-
HEAD SCREW

GLASS TUBE 1/2” DIAMETER
(PRESSURE FIT) HOLE IN PLYWOOD
_-—_ 1/2 WAY THROUGH

HEAVY-DUTY
COILED
CAP FROM
\ COLLECTION BOTTLE

PeyWO0D PLASTER OF PARIS

3/4” ROUND-
HEAD SCREW

(PRESSURE FIT)
ers 1/4” MALE MONO
PHONO PLUG

1/4” FEMALE MONO

BOTTOM OF BOTTLE CUT OUT PHONO JACK

AND REPLACED WITH 30-MESH
FIBERGLASS PLASTIC SCREEN

ES SURPLUS 7.62 mm! +
AMMUNITION

HOT GLUE ADHERES | BOX, PADDED f

SCREEN TO BOTTLE.} 'NSIDE

TRIM OFF EXCESS CONTAINS 12-VOLT
B MOTORCYCLE BATTERY

30-MESH FIBERGLASS PLASTIC
SCREEN PUSHED INTO BOTTLE
TO ABSORB IMPACT OF INSECTS

Figure 1.--Schematic diagram of modified
Car-Vac: (A) vacuum with modification in
the front cover; (B) collection bottle;
(C) baitery box.

(9.5-mm) flexible plastic tube that passes through the block and
feeds into a collection bottle Inside the cover. The bottle
(fig. 1B) is screened on one end to permit airflow and threaded
on the other so that it can be screwed into a cap countersunk on
the inside of the block (fig. 1A). The smal! size of the suction
tube permits selective vacuuming of Individuals without sucking
up large amounts of dry needles and other plant debris from the
cloth. Because specimens are pulled through the tube with
considerable velocity, a piece of fiber glass screen placed in
the vial helps prevent damage to their soft bodies.

Power source for the vacuum is a 12-volt motorcycle battery
carried in a padded surplus ammunition box. The box Is fitted
with a conventional mono plug for connecting the colled, heavy
duty electrical cord from the vacuum (fig. 1C).

Figure 2.--(A) Pack-frame with mounted
battery and side holster for vacuum; (B)
collecting arthropods from beating cloth.

A lightweight, cargo-type pack-frame is used for carrying Ecth
the battery and vacuum in the field. The battery box rests on
the frame's bottom support and is held in place by straps. The
vacuum is carried in a side holster attached to the frame's web
waist belt (fig. 2A). Weight of the entire unit is 20 pounds

(9 kg). With this arrangement a person carrying the unit can
operate the vacuum with one hand and have the other hand free to
hold a beating cloth (fig. 2B). Under normal use, a fully
charged batter will operate efficiently for 8 hours before
needing recharging.

The equipment described here has been especially successful in
collecting insects and spiders from the hand-held beating cloth
described by Paul (1979). In our studies, 18- to 20-inch (45- to
50-cm) branches of true firs or Douglas-fir were sampled. With
the cloth held underneath, the branches were vigorously rapped
with a beating stick. AII arthropods that dropped off were
vacuumed into the collection bottle within seconds of striking
the cloth (fig. 2B). We found that a single 1-ounce (30-m!)
bottle usually accommodated the arthropods from 30 such

branches. A full bottle is easily removed by unscrewing it from
the vacuum and attaching a cap to prevent escape. The collection
can then be preserved by dropping the whole bottle in a small jar
of 70-percent alcohol. By slightly loosening the screw cap, the
alcohol will quickly circulate through the screened end of the
bottle.

Literature Cited

Despite the narrow suction tube, some needles, bud scales, and
other debris are irevitably collected and make separation of
specimens in the laboratory more difficult. Arthropods can
usually be seperated from plant meterial by emptying the vial
contents into a shallow pan of water. Because cf their lighter
weight, most arthrcpeds float to the top where they cen be easily
screened off and preserved in alcohol.

We have used this equipment for 3 years to study arborea!
arthropod communities in the Pacific Northwest and have had
remarkably consisient results. For example, a typice: sample

of 150 fir branches (3 branches on each of 50 trees) yielded 8 to
10 arthropod orders--usually dominated by spiders (Areneae)

(fig. 3). Because the folliage is systemetically sampled, total
numbers collected can also be iransiated into density values and
the relative abundance of potential predators easily assessed.

4
3
3
2

i:
© 40
‘6 35
= 30
O

S 5
20
15
10
5
0

Figure 3.--Numer ical
= | composition of arth-
N , Naya eee | ropods, by Oreo:
(sample size = 203)
collected by beating
and vacuuming the
contents from 150
18= to 20-inch
(45- to 50-cm) fir
branches on a plot
near Fort Klamath,
Oregon.

Lepidoptera
Coleoptera
Hymenoptera

| Hemiptera
Homoptera
Neuroptera
Ephemeroptera
Pscoptera

Paul, H.G. How to construct larval sampling equipment. Agric.
Handb. 545. Washington, DC: U.S. Department of Agriculture;
UTS S SP tore