What Good Are They? - NH Fish and Game
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What Good Are They?
BY KAREN FINOGLE
Karen Finogle is a freelance writer from Newmarket, NH who still
swats at black flies, despite her newfound appreciation of them.
A female Aedes mosquito.
Photo by Dennis Kunkel Microscopy, Inc., www.pbrc.hawaii.edu/~kunkel
2 January/February 2000 • WILDLIFE JOURNAL
They bother us through some of the best times of the year. Then they finally go away. But
these nasty bugs really have some value to the ecosystem.
WAT. SLAP. THWAT. Black flies breed exclusively in running water, both
Ah yes, it must be springtime in New Hampshire. Never fast moving and sluggish. After a blood meal, females lay
mind the singing birds and the blooming flowers, spring their eggs on vegetation in streams or on the water surface.
arrives here on the wings and whine of bloodthirsty black Eggs will spend winter submerged in streams and hatch in
flies and mosquitoes. the spring once the water temperatures reach 40 to 50
Amidst the budding beauty around us, it’s a season of degrees.
war. We tuck our pant legs in our socks and arm ourselves The worm-shaped larvae hatch and attach themselves
with citronella, bug spray, and anything else that someone to submerged objects, such as rocks or grass. Larvae of
once told us “works pretty good.” It’s us or them — the some black fly species will spend the whole winter under-
blood-filled versus the bloodthirsty. And, in the end, battle water. The larvae filter particles from the water column,
worn and scarred, we generally lose, reclaiming our territory consuming bacteria and other microorganisms as they clean
only after the enemy has left. the water.
But what do we really know about our enemies? Did “Black flies are suspension feeders,” according to John
you know, for instance, that their ancestors date back 150- Burger, a zoology professor at the University of New
200 million years ago? If we’re talking seniority, they’ve got Hampshire who specializes in mosquitoes and black flies.
us beat by a mile. “You have all this stuff suspended in the water column, and
Have you considered that maybe they really they filter it out. It’s basically mostly vegetable, which they
aren’t our enemies? Though they obviously concentrate into a meat, which is then fed upon by fish and
feed on us, mosquitoes and black flies are whatever else feeds on aquatic larvae.”
also food for all sorts of creatures, includ- Among the predators of black fly larvae are fish,
ing fish, birds and other insects. insects, amphibians and others. The larvae are victims, as
And consider this the next time we are to black flies, and their sacrifice helps support a
you’re about to smack a mosquito on diverse ecosystem. A large population of adult black flies —
your arm. There are more than 2,500 awful as it is for us — indicates a healthy stream, because
species of mosquitoes throughout the the larvae have little tolerance for pollution.
world, 43 of which are known to A mature black fly larva weaves a cocoon, pupates into
occur in New Hampshire. Of those an adult and rides a bubble of air to the water surface.
43, only 28 species are known to feed Adults mate near the breeding site, and females will leave in
on humans, and just 14 of the 28 search of blood immediately after that. Many black fly
species are considered to be serious species seem to feed only on the blood of birds.
pests due to their abundance. That
doesn’t sound so bad, does it?
MOSQUITOES: “AQUATIC COWS”
Likewise, about 2,000 black fly species occur through-
After enduring black flies in the spring, it’s time for the
out the world, but only 40 species are known to exist in the
mosquitoes. Mosquitoes start emerging by mid-May in
Granite State. Of those 40, only two species are considered
southeastern New Hampshire and the wave gradually
significant human biters, and two other species are consid-
spreads north, reaching the North Country by late May.
ered annoying but don’t generally bite.
Biting species of mosquitoes reach their peak of annoyance
Not ready to sign a peace treaty quite yet? A look at
by late May through the first half of June.
their life cycles shows some of their ecological benefits.
Seacoast residents have it worse. One salt marsh
species breeds in very large numbers and there are lots of
BLACK FLIES: NATURE’S LITTLE FILTERS them by late July or early August. Relief from these insects
First to annoy us humans are the black flies, which is finally felt by mid-September.
begin emerging from mid- to late April in southern New Like black flies, mosquitoes have four distinct life
Hampshire and last through the end of May. In stages: egg, larva, pupa, and adult. But unlike black flies,
northern New Hampshire, black flies appear by mosquitoes require standing water to reproduce. Their
mid- to late May and can last into July in breeding areas include vernal pools, marshes, ponds, tree
the mountains. One species hatches holes, stumps, tires, swimming and wading pools, cans,
late along northern New Hampshire’s ditches and culverts. If it holds water, mosquitoes can breed
large rivers in August and Septem- there. And generally, a wet summer means more mosqui-
ber. This species swarms but toes.
seldom bites. continued on next page
WILDLIFE JOURNAL • January/February 2000 3
continued from previous page ARTWORK BY BARRY FLAHEY, COURTESY OF THE CANADA DEPARTMENT OF NATIONAL DEFENSE.
Once hatched, the larvae secretions and so forth,” Burger
feed on vegetable matter in the said. “It’s well known now that
water. Professor Burger calls these some of the proteins found in the
larvae “aquatic cows.” saliva are pharmacologically very
“They turn plant-based active. We don’t really know yet
organisms into meat,” Burger said. the extent to which any of these
“It’s analogous to what a cow substances will ultimately prove
does. It takes a material which is to be useful in medicine; but it’s a
low energy and concentrates it good idea to keep your options
into a much higher energy, which open.”
then, other members of the food The mosquito’s popularity
web take advantage of.” with fish is certainly beneficial to
According to Professor LIFE CYCLE OF A people who fly fish. According to
Burger, this high-energy food, the BLACK FLY Mark Beauchesne, who heads
mosquito larva, are eaten by all Fish & Game’s Let’s Go Fishing
sorts of predators, everything from Program, the mosquito is imitated
fish to beetle and fly larvae and by many fly-tyers.
many predacious flies. Beauchesne offers his own
The larvae, or wigglers, molt defense of black flies by asking
four times before becoming a the question: “What’s worse,
pupa, or tumbler. The adult black flies or shoveling snow.” He
mosquito emerges from the pupal supports black flies because they
stage in less than a week. Adults Clockwise from top: adult female; eggs on plants near “are a part of fishing. They are a
mate before the female leaves to surface of flowing water; larvae attached to part of the experience of being
seek blood. In the world of black streambed; pupae in cocoons attached to vegetation; out there.”
flies and mosquitoes, females get adult rides air bubble to surface, where it emerges. Professor Burger’s defense
the bad rap, as they are the only of the insects supports the
ones that feed on blood. The male ecological benefits.
insects feed on the nectar of flowers. alleviate our discomfort and our dislike. “I guess I come down on the
But are there other benefits? good side, if only because annoyance
DEFENDING THE BUG From a medical standpoint, the tends to be fairly temporary,” Burger
Obviously, adult black flies and jury is still out. There’s ongoing said. “At least in terms of black flies,
mosquitoes are an abundant food source research to determine whether these those larvae are in the stream for long
for birds, bats and predacious flying insects might eventually benefit periods of time, filtering the water
insects, as well as parasites. As we know humans. column and providing food. The
each spring and summer, their predators “There has been some work done adults don’t live all that long. Mosqui-
don’t impact the species enough to on the chemistry of the various salivary toes are the same way.”
Deet (N, N-Diethyl-3- Oil of citronella: Found in flies and mosquitoes. Instead, they’re
Methylbenzamide): Formulas with candles, torches and coils that are burned probably frying larger insects that
20 to 30 percent are effective unless to produce a smoke that deters the bugs. feed them.
in a heavily infested area. Works on It’s usually less effective than repellents Electronic mosquito
both mosquitoes and black flies. applied directly to the clothes or body. repellers: Several laboratories have
Apply higher concentrations to Clothing: Black flies and mosqui- found the devices are completely
clothing to avoid skin irritations. toes are less attracted to light colors, ineffective at repelling mosquitoes.
Piperidine: Not yet on the such as whites, yellows or light blues. Avon Skin-So-Soft: A hung
market; currently being tested by the Black flies can find any exposed flesh, jury. Studies have proven that there
U.S. military. so keep shirtsleeves and front buttoned is no scientific evidence as to its
Permethrin: Soaking clothes in and tuck pant legs into socks or boots. effectiveness but can thousands of
this insecticide can provide protec- Shoulder-length headnets provide welt-free customers be wrong?
tion through several washings. Many excellent protection. Individual skin chemistry varies
manufacturers also sell outdoor Bug zappers: There’s no widely, so it may indeed work for
clothing impregnated with Permethrin. evidence that they really control black some folks in low bug areas.■
4 January/February 2000 • WILDLIFE JOURNAL
ARTWORK BY BARRY FLAHEY, COURTESY OF THE CANADA DEPARTMENT OF NATIONAL DEFENSE.
PROTECT YOURSELF Mosquitoes enjoy hanging
You may know and even out on tall grass or vegetation
appreciate black flies and mosqui- along wooded areas. Avoid these
toes now, but as they swarm areas, or expect the worst if you
around your head this spring, you venture near.
still have one thing on your mind: Use screens on your home
It’s us or them. and make sure there are no holes.
OFFENSE: There are several These buggers can get through
methods of controlling mosqui- just about anything.
toes and black flies on a large Space sprays (with
scale, but most of these methods pyrethrum or synthetic pyre-
should be done by someone who throids) can be used for temporary
is certified by the New Hampshire LIFE CYCLE OF A relief, but it will be very temporary.
Department of Agriculture, MOSQUITO Outdoor foggers can also
Markets and Food. One recent provide a brief respite. Hand-held
development that is having a foggers containing pyrethrum or
substantial impact on the control malathion can be used; there are
of these insects is the formation of also attachments available for
a microbial pathogen: Bacillus tractors and lawn mowers. But
thuringiensis variety israelensis strong-flying black flies may
(BTI). It’s a spore-forming escape the fogging in time to
bacterium found naturally in soil. return for a meal later on.■
It kills only the larvae of mosqui- Counter clockwise from top: adult female; raft of
toes, black flies and a group of eggs on water surface; larva suspended at water WANT TO LEARN MORE?
midges. The good thing about this surface; pupa suspended at water surface; adult THE AMERICAN MOSQUITO
larvacide is that it is not toxic to emerges into air from floating pupal skin. CONTROL ASSOCIATION.
humans or wildlife and won’t www.mosquito.org.
contaminate the water. they are at their peak. Try venturing out Mosquito Bytes.
The AMERICAN MOSQUITO CONTROL at the crack of dawn, mid-day, or after www.whyfiles.org/016skeeter/kill.html.
ASSOCIATION has a few other offensive sunset. And remember that black flies Habits and Control of Mosquitoes,
strategies: really like humid days, especially before Black Flies & Biting Gnats in New
Remove tin cans, old tires, a storm. Hampshire. Publication by the UNIVER-
buckets, unused plastic swimming pools Mosquitoes are most active at SITY OF NEW HAMPSHIRE COOPERATIVE
and other things that can collect water. dusk and on warm, cloudy days, so EXTENSION. 603-862-2346.
Don’t let water accumulate at during the brief time of season when Manufacturers of protective mesh
the base of flower pots or pet dishes for black flies and mosquitoes co-exist, you clothing: www.bugbaffler.com,
more than two days. may need a bomb shelter. www.insectout.com
Remove and standing water
under or around structures. Keep rain What About
gutters clear of debris.
Change water in bird baths and
wading pools at least once a week. percent of people who get bitten and
Stock ornamental pools with top become infected will get severely ill.
While there are a few benefits The chances you will become severely
feeding predacious minnows.
from mosquitoes – namely their place ill from any one mosquito bite are
Drain or fill tree holes and in the food chain – one drawback has extremely small. The virus doesn’t
stumps with mortar. surfaced on this continent in recent seem to spread from people-to-
Eliminate standing water years: West Nile encephalitis. It’s an people, or from birds to people.
around animal watering troughs. inflammation of the brain caused by a Health experts advise that the
Irrigate lawns and gardens virus transmitted by mosquitoes, which best way to protect yourself from the
carefully to prevent build-up of standing get it by biting infected birds. West Nile virus is by protecting
water. So far, the risk of getting severely yourself from mosquitoes. Follow the
Install screens that have a 16-18 sick is pretty small. According to the tips in the accompanying sidebar.
Centers for Disease Control, even in For more information, visit
mesh.
areas where mosquitoes carry the www.cdc.gov/ncidod/dvbid/westnile
DEFENSE: virus, very few mosquitoes – much less or www.dhhs.state.nh.us/
Black flies are only active than 1 percent – are infected. If the commpublichealth/WestNile.nsf, or
during the day. Avoid going out during mosquito is infected, less than 1 call 866-273-6453.■
the morning and afternoon hours when
WILDLIFE JOURNAL • January/February 2000 5You can also read
