NAVMED P-5010-8 - Navy Medicine - U.S. Navy

8-56 CHAPTER 8. NAVY ENTOMOLOGY AND PEST CONTROL TECHNOLOGY 8-56
competing light sources, windy areas, and industrial
fumes. Also avoid trapping in livestock and
bird roosting areas because mosquitoes are less
easily attracted to light after taking a blood meal.
Optimum results will be obtained in areas with
adequate vegetation and high humidity. A shift
of a few meters can make a substantial difference
in results. Therefore, if trapping results are poor,
change the trap locations before reporting the
absence of mosquitoes in the area. In addition to
indicating what species are present, trapping
signals the emergence of males that emerge before
the females and congregate near the breeding site.
This allows treatment of a population before a
major increase in the number of adult females
occurs, thus, lowering the breeding potential. For
some of the Anopheline species that are not
strongly attracted to lights, collections are made
at resting sites. This is done by sweeping the
vegetation with an insect net or by using an
aspirator (or killing tube) and a flashlight. The
aspirator is made of rubber or plastic tubing joined
to a piece of rigid clear plastic tubing [0.9 cm
(0.37 in) inside diameter] with a piece of netting
in between for a filter. Cool, dark, and humid
areas are checked, including culverts, bridges,
caves, overhanging stream banks, wells, and
buildings. In areas with few resting sites a variety
of artificial devices such as boxes, barrels, and
kegs can be established. For a detailed discussion
of mosquito collection, a "Mosquito Surveillance
Guide" is available from EPMU's and DVECC's.
2) Curation. Adult
mosquitoes are very delicate and must be
handled carefully to avoid loss of scales or
appendages essential to their proper identification.
Natural scale discoloration, caused by
moisture, must also be prevented. Consequently,
to avoid contact with moisture that
condenses in ethyl acetate or chloroform killing
tubes when exposed to heat or the sun, remove
the mosquitoes as soon as they are killed and
periodically wipe the barrel of the tube dry.
Reared adult specimens to be preserved should
be kept alive for at least 12 hours to allow them
to harden, and then pack them in pill boxes.
Pillboxes are preferred over glass, plastic, or
metal containers because they are permeable. This
helps to prevent any fungal growth caused by a
build up of excessive moisture from the drying
specimens and heat from the environment. Prepare
the box for shipping by cutting two strips of
soft tissue paper slightly larger than the lid. Place
a thin, very light wisp of cotton in the bottom of
the box, and cover it with one paper slip. Being
slightly larger than the box, the paper’s tucked
edges against the sides will hold it firmly. Place
the collected mosquitoes on this paper and tuck in
the second paper slip until it just contacts the
mosquitoes. Be sure the covering slip will not
become dislodged. Over the top paper slip, add
another wisp of cotton that is barely large enough
to touch the lid when it is closed. Do not, under
any circumstances, pack mosquito adults between
layers of cotton, cell cotton, or similar fibrous and
heavy materials. The collection data should be
placed within the container between the lid and the
top layer of cotton. Data may also be recorded on
the lid of the container. Placing the containers in
an excelsior-padded and properly labeled mailing
tube completes packing.
(c) Flies. Adult flies can be
collected with an insect net or a variety of traps.
If a natural attractant is available use a 76mm
(3.0 in) diameter wire screen cone with an
inverted screw top to trap domestic flies. Place
the cone over the attractant and flies. Then place a
dark cloth over the cone. The cone is then agitated
and the flies will move upward toward the light in
an effort to escape. The sliding door of the trap is
then closed, blocking the mouth of the bottle.
Lacking a natural attractant, all-purpose baits
consisting of a mixture of fish heads, chicken
entails, vegetables and fruit may be used. The
cylindrical screen trap placed several inches above
the bait should have a funnel shaped, upward
pointing bottom, and a removable top. As the flies
leave the attractant, they are funneled into the trap.
Since they generally do not fly downward to
escape and the funnel opening is difficult to find,
few flies will escape. Fly larvae (maggots) and
adult specimens of delicate flies, such as sand
flies, culicoid biting flies, eye gnats and blackflies,
may be preserved in 70 percent ETOH as
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