(1) KiIIing jars. Light traps attract many species of mosquitoes when placed
in remote areas away from other Iight sources. As the adult mosquitoes approach the
Iight, they are blown downward into the kiIIing jar or a mesh bag. The kiIIing jar is made
from a pint or quart jar. Cut a vapona strip in half lengthwise; then cut each half into
quarters (wear a respirator, protective gloves, and use a utiIity knife to cut the strip).
Wrap each piece of vapona in tissue paper (to prevent insects from sticking to the
greasy surface) and place a chunk in each kiII jar. The jars should be clearly labeled as
to their contents, marked as poison, kept tightly sealed, and stored in a locked container
when not in use. Vapona strips/chunks are poisons and should be handled with extreme
care. KiIIing jars may also be made by saturating chunks of rubber bands in chloroform,
placing them in the bottom of the jar, and covering them with a layer of cotton topped
with perforated cardboard. This type of kiIIing jar has to be recharged with chloroform
quite often.
(2) Location. The Iight trap is mounted on a post or hung from a tree with
the Iight about 6 feet above the ground. It should not be placed near other Iights, in
open areas subject to strong wind, or near any plant or factory giving off strong odors,
smoke, or gas. Preferred locations are between the installation and the breeding area.
Traps are operated for 3 to 4 nights a week, unless the primary purpose is to detect the
presence of uncommon species in which case the traps should be operated every night
for 7 days. They are turned on just before dark and turned off just after daylight.
Electric (AC) traps can be controlled with an adjustable electric timer. The solid-state,
Army miniature (SSAM) Iight trap's battery operated system is controlled with a photo
sensitive circuit. The specimens should be removed each morning and placed in a
properly labeled box untiI they can be sorted and identified. Special attention should be
given to the kiIIing jars. They should be fully charged at all times so as to make a quick
kiII as soon as the mosquitoes are blown- into the jar by the electric blower.
(3) Delivery of specimens. Specimens should be delivered to the laboratory
as soon as possible so the mosquitoes may be separated from other arthropods. Mold
wiII grow on trap collections that are left in sealed airtight containers. Alternatively,
insects in samples left to dry before sorting are very often brittle, resulting in excessive
damage to specimens. Samples are sorted by emptying the specimens onto a large
sheet of white paper or into a large white enamel pan. A pair of fine pointed forceps is
used to gently separate the mosquitoes from the other arthropods. After the adult
mosquitoes are separated, they are packed for shipment as outlined in lesson 4 if they
are to be shipped to another location for identification.
f. Resting Station Collections. Adult mosquitoes rest quietly in dark, cool,
damp places when not seeking a blood meal. Collections made in houses, stables,
sheds, culverts, outhouses, caves, hollow trees, and similar natural shelters wiII give a
good indication of the species of mosquitoes present' in an area. With experience, one
is able to evaluate the suitabiIity of shelters by casual inspection. Dwellings, especially
when unscreened, often prove to be satisfactory resting stations, being especially
important when mosquito-borne diseases are being investigated.
MD0170
3-8
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