| Don't
Bug Me: Canoe Country Insects by
Steve
Volkening
The
two questions most asked of those just returned
from a canoe trip to the Boundary Waters region
are "how was the fishing?" and
"how bad were the bugs?" Depending
upon the time of the year and the weather, it
may sometimes seem as if the insects were biting
more than the smallies or walleye.
Biting insects such as mosquitoes, black
flies, and no-see-ums certainly can be a
nuisance. But thanks to insect repellents
containing DEET (n, n,
diethyl-3-methylbenzamide), tightly woven,
high-tech fabrics, headnets, and fine screening
in our tents, they are not nearly as bothersome
to us today as they once were to the early
explorers and voyageurs who paddled this area
long before us.
Besides, only a few of the insects we
encounter in the North Woods are pests. We
probably pass by scores of insect species each
trip without giving them a second thought. Most
bugs are quite beneficial, too. Many other forms
of plant and animal life would not survive
without them. The majority of the world's
flowering plants depend upon insects to
pollinate them. We wouldn't be able to snack on
blueberries along the path if it weren't for the
pollinating efforts of the blackly. Insects also
make up a major part of the diet of many other
creatures.
Insects have been around for a long, long
time. The first primitive insects first appeared
on earth about 350 million years ago. It is
amazing to think that some of the same bugs we
see today were around to bite the dinosaurs!
Insects are the largest and most successful
group of animals in the world. Over one million
species have been identified and there are
estimates of another five to ten million more
which yet need to be described. In North
America, we have between 90,000 and 100,000
species.
Bugs have an incredible ability to survive in
many extreme habitats around the world. Mountain
climbers have seen butterflies at 16,500 feet
and a hot air balloonist once found a honeybee
at 30,000 feet. Blind and colorless crickets
live in caves deep below the surface. Snow
mosquitoes are active even in cold weather when
there is snow on the ground.
All insects have a hard outer shell or
exoskeleton covering a body made up of three
parts - head, thorax, and abdomen. Each part
serves a different function. The head contains
the eyes, a pair of sensory antennae, and
specialized mouthparts. Beetles have mandibles
(jaws) for cutting and chewing. Flies have a
sponge-like tongue to absorb liquids. Mosquitoes
have a needle-like mouth to pierce skin. The
thorax bears three pairs of legs and usually two
pairs of wings. All insects have six legs.
Spiders are often lumped in with bugs, but they
have eight legs. Spiders are arachnids - a whole
different class of animals. The insects' abdomen
contains organs for digestion and reproduction.
Insects breathe through openings called
spiracles, which are found in the sides of their
thorax and abdomen.
Insects were the first creatures to develop
the ability to fly. This made it easier for them
to evade predators and find food. Their wings
are made of cuticle, the same substance as our
outer skin. Their wings are hinged to their
thorax and both pairs are usually hooked
together. Dragonflies can beat theirs
alternately, giving them greater
maneuverability. Flies are one of the few insect
families with just one pair of wings. Still,
they are remarkable fliers - able to fly
backwards, sideways, and even upside down! Most
insects can fold their wings when not in use.
This makes it possible to squeeze into small
spaces to find food, shelter, and escape from
predators.
Water Bugs
Since the numerous lakes and streams of the
Boundary Waters Canoe Area Wilderness and
Quetico Provincial Park are the region's prime
attraction, let's first look at two common
insects which live in the water - Water Striders
and Whirligig Beetles.
Water Striders are also called
"Skaters" or the "Jesus Bug"
because of their ability to "walk" or
skim across the surface of the water. They are
slender insects with short forelegs and much
longer middle and back legs. The forelegs are
used by these predatory bugs for grasping prey.
The last four legs are equipped with tiny
water-repellent hairs that keep them on the top
of the water. These Striders should not be
confused with the eight-legged Fisher Spider,
which is 5 inches long. These hunting spiders
are also often seen on lily pads. They can run
on top of the water and even dive below in
search of a meal.
Striders are little bugs which range in size
from 1/16 to 1-1/2 inches long and are usually
dark brown. They dart about on the surface film
of the water held up by their widely-spread four
rear legs. They have special sensory organs on
their legs to detect ripples. They then quickly
move in to capture the mosquitoes larvae or fly
which fell into the water. These sensors also
play an important role in courtship. Striders
communicate to potential mates by sending out a
special series of ripples of their own.
Females lay eggs in parallel rows at the
water's edge. They soon hatch, and the nymphs
emerge. After about five weeks, the nymphs
mature into adults. They are able to survive the
frigid northern winters by hibernating under
leaves near the shore. They live long enough
into the next spring to begin another
generation.
Over five hundred species of Water Striders
are found throughout the world. Most of them
live in fresh water streams and lakes. Some of
them, however, live in the warm tropical oceans.
The Whirligig Beetle is another common
aquatic insect that glides across the surface of
quiet lakes and streams. These small beetles
(1/8 - 5/8 inches long) are often seen in groups
zig-zagging in circles in a quiet eddy. They
float on the surface and don't suspend
themselves above it like Striders.
Like Striders, Whirligigs are hunters both as
adults and in their larval stage. The adults
hunt aquatic insects and other bugs which may
have fallen in the water. The larvae eat snails,
mites, and larvae of other species. These
beetles are expert hunters because of their
unusually divided compound eyes. The upper and
lower parts enable them to see both above and
below the surface of the water at the same time.
Their antennae can detect ripples on the
surface and distinguish between wavelets caused
by prey, by obstacles in the water, or by the
movement of other whirligigs. Their short
paddle-like hind legs help them maneuver. While
hunting on the surface, they breathe through
spiracles on their abdomen. When they dive
underwater, they carry an air bubble down with
them.
Female whirligigs lay their eggs on submerged
plants. When the larvae are fully developed,
they crawl out of the water and construct pupal
cases out of grains of sand and bits of plant
debris. Then, they go through a final
metamorphosis and emerge as adults. They can
live for one year. Some species over winter on
plants or in the mud, while others hibernate in
leaf litter at the water's edge.
Mayflies
The Mayfly's scientific name is Epheroptera,
which means "living for a day." Some
species don't even live as adults that long.
Some emerge out of the nymph stage in the
evening and die before dawn. Other species may
live for just a day or two. However, they live
under water as nymphs for two or three years.
Mayflies are one of the oldest surviving
insect families in the world. They first
appeared nearly 350 million years ago. Of the
2,500 species of mayflies still found today,
about 500 live in North America. They are unique
among insects because they alone undergo a final
molt after their wings have formed.
They have soft bodies, long slender
forelimbs, and two or three filament - like
tails that can be twice as long as the rest of
their body. Their mouthparts are poorly
developed and they don't eat as adults. They
also have no digestive system. They live only
long enough to reproduce and survive briefly as
adults on energy reserves.
Swarms of flying mayflies busily mating is a
familiar sight in Canoe Country in late May and
June. The female lays from 500 to 1000 eggs.
After breeding, the adults tire and weaken as
their stored energy runs out. They fall into the
water and become fish food. Some of the finest
artificial trout flies are patterned after the
mayfly.
Dragonflies and Damselflies
Nearly everyone who has spent anytime
outdoors around a pond has seen dragonflies
zipping through the air. With their large eyes
and superb flying ability, they are highly
effective predators. Best of all, their favorite
food is mosquitoes.
Dragonflies are another ancient insect form,
dating back to the days of the dinosaurs. Over
5000 species still remain today. Dragonflies and
the closely - related damselflies are similar in
appearance. Dragonflies are generally larger and
have much thicker bodies. When at rest, they
hold their wings out horizontally from their
thorax. Damselflies are more slender and
delicate looking. They rest with their wings
folded over their tails.
The nymphs of these two insects are amazing
hunters. A book on insects I saved from the
early 1960s describes the nymph as a
"bloodthirsty ogre, stalking endlessly for
living prey." Like something out of a
monster movie, the lower jaw of the nymph can
thrust out towards its prey at lightening speed.
It can extend for half its total body length and
is tipped with two inward-facing barbs. It feeds
on mosquito larvae and even small minnows and
tadpoles.
There are several different dragonfly
families. Darners are the largest (2-1/4 to
4-3/4 inches long) and the fastest flyers. They
are usually a beautiful metallic green, blue, or
brown. Their clear-colored wings are up to six
inches long. They are commonly found around
marshes. Darters or Clubtails are smaller and
less colorful. They are aptly-names because
their abdomen swells at the end to form a
"club." They dart around and fly in an
unpredictable pattern as they search for
mosquitoes. They are most usually found along
rives and the shores of large lakes. Skimmers
are recognizable because of their wings. These
are often marked by spots or dark bands and are
larger than the length of their body. True to
their name, they skim quickly over the surface
of ponds, but are also just as likely to hover
like a helicopter.
Damselflies fly with slower wing beats. They
appear more like a fluttering moth or falling
leaf than their dive-bombing dragonfly cousins.
While male and female dragonflies are usually
the same color, male damselflies are more
brightly colored than females. Female
dragonflies drop their eggs in the water, but
most damselflies species make a slit in aquatic
plants and lay their eggs inside them. A few
damselflies lay their eggs on plants above the
lakeshore. When the vegetation collapses in the
winter, the eggs fall into the water.
No-See-Ums
Also known as "Punkies," No-See-Ums
are a group of pesky little insects able to
squeeze through tent screens and mosquito
netting. These tiny bugs are actually members of
the midge family. There are two kinds of midges
- biting and non-biting.
Biting midges are bothersome little bugs with
a big-time bite. Nearly 4,000 species exist
worldwide, mostly near the water. They are
generally smaller than 3/16s of an inch. They
have short, strong legs and dark patterns on
their wings. They also have piercing mouthparts
to suck blood from people and fluid from insect
bodies. The females bite people and other
animals because they need blood to produce their
eggs. Their bite is quite annoying despite their
small size. In tropical areas, these midges
transmit worm parasites to humans and carry
animal diseases, but they are also pollinators
of such important crops as rubber and cocoa.
Non-biting midges are tiny flies which look
like small scale mosquitoes. However, they have
no functional mouthparts and can't bite. The
adult flies live only two weeks, but most of
their two to three year life span is spent as
larvae. In some species, the larvae have red
hemoglobin in their body fluid and are known as
"blood worms."
Biting Flies
There are over 122,000 species of flies
scattered around the earth. They are unusual in
the insect world because they have only a single
pair of wings. Their hind wings are reduced to a
small, nonfunctional club-shaped balancing organ
called halterers. Although most people dislike
them, flies play an important role in the
ecosystem. They are vital as pollinators and
decomposers. They also spread disease and damage
crops. In the Boundary Waters region, three
species - the Deerfly, Horsefly, and Blackfly -
are despised because of the painful bites they
inflict.
Deerflies and Horseflies are members of the
same insect family. They are stout and
large-headed flies with large bulging eyes.
Unlike other members of the fly family, they can
fly silently. Sometimes canoers aren't aware
that they are even around until they receive a
painful bite. As is the case with most biting
insects, only the females bite. They have
cutting and slashing mouthparts designed to cut
through skin. They then soak up the blood with
an absorbent, sponge-like tongue. Males feed on
nectar and pollen.
Deerflies are 3/8-5/8 of an inch long. They
have a flattened body shape and yellow-green
markings. Their wings have light cross bands.
They are often found buzzing around our heads.
Horseflies are 3/4 to 1-1/8 inches long. They
are blackish gray and have transparent wings.
They often bite ankles. Because their saliva
contains an anticoagulant that prevents
clotting, their bites continue to bleed for
several minutes.
Blackflies are a small (1/16-1/4 inch long),
somewhat squat dark gray or black fly with
rounded wings and bulging eyes. Because of their
distinctly humpbacked shape, they are sometimes
called "Buffalo gnats" or
"Humpback Flies." About 300 of the
world's 1,600 blackfly species are found in
North America. Some South American species carry
a roundworm parasite which causes human
blindness. Some species also transmit waterfowl
malaria, which accounts for nearly one half of
the deaths of ducks, geese, and swans. In Canoe
Country, one species feeds exclusively on loons.
Blackflies hatch by the millions in late May
and early June. During these few weeks they can
make things miserable for those unprotected by
netting, proper clothing, and repellents. They
seem to be attracted to the edges of clothing
such as collars and cuffs. They are especially
attracted to the color blue, so jeans aren't a
good choice for an early summer canoe trip.
(Besides, jeans are heavy and take forever to
dry when they become when wet. and you can
almost certainly count on them getting wet
during your trip.) Blackflies don't seem to like
the shiny or glossy surface of the new high-tech
fabrics, but they do like the rough texture of
wool and cotton. As with other biting flies,
just the females bite. Male blackflies feed on
nectar and are the major pollinator of North
Country blueberries.
The females bite is more painful than a mosquito
and usually causes more swelling. Its saliva
contains both an anticoagulant to slow clotting
and a compound which affects our nervous system.
Blackflies are most often found around
running water. The female lays her eggs near
riffles and the base of waterfalls because that
is the best place for the larvae to develop. In
some prime locations there can be as many larvae
as one million per square yard. The larvae
attach themselves to rocks in the oxygen and
food rich fast current by means of a suction
disk and silk threads. There, they filter feed
on plant material and tiny aquatic animals. The
fully grown larvae pupate into cocoons that coat
the rocks and plants. Before it hatches into an
adult, it creates an air bubble and rides it to
the surface.
Mosquitoes
Everyone knows about 'squeeters! World-wide,
there are over 3000 species with more than 150
species found in North America. They are among
the most lethal animals on the planet because
they carry such deadly diseases as malaria and
yellow fever.
There is a growing concern about the West
Nile virus which is also spread by mosquito
bites. Actually, migrating birds are the primary
carriers of the virus. West Nile is much worse
on the birds than people, and millions of birds
were killed by it in 2002. These birds spread it
to mosquitoes when they are bitten, and then the
'squeeters pass it along to a few of us. The
odds of coming down with West Nile on your next
canoe trip is very slight. Less than 1% of
mosquitoes carry the virus. Less than 20% of
people who contract it develop the flu-like
symptoms. Of these, less than 1% develops any
serious consequences.
The New England Journal of Medicine reports
that insect repellents containing 25% DEET keep
mosquitoes away for up to five hours. But, be
careful. DEET can damage your good Gore-Tex
raincoat. Repellents using eucalyptus oil work
for about two hours. Citronella-based lotions
work up to one hour.
As with the other biting insects, only female
mosquitoes bite. Only females also make that
annoying high-pitched whining noise. They make
it by rubbing and vibrating bristles on their
thorax as a mating signal. Before they are
killed by the first frost, females lay their
eggs in pools of water. When the ice melts in
the spring, the sun incubates literally billions
of their eggs. They soon hatch into larval
wigglers. They live in this larval stage for
about one week before they pupate. Depending
upon the water temperature they emerge on swarms
of hungry adults about one week later.
Insect Trivia
Bugs are some of the most remarkable creatures
in God's amazing creation. As you sit around the
campfire on your next canoe trip swatting
mosquitoes, here is some trivia to share with
your paddling buddies:
- There are 50,000 facets on the compound
eye of a dragonfly.
- Cockroaches are so hardy that they can
live for months on a diet of nothing more
than dust.
- Blister beetles contain the chemical
cantharidim, which causes blisters on human
skin.
- Bed bugs feed on human blood. When people
aren't around, they can survive for up to 15
months without food.
- Here is how ladybugs got their name:
During the Middle Ages, an invasion of
insect pests nearly destroyed the grape
vines. Ladybug beetles saved the grapes by
eating the pests. In appreciation, they
dedicated the little red insect with black
spots to "Our Lady."
- The hearing organ of crickets and katydids
is located on their front legs.
- The neck of a praying mantis is so
flexible that it can turn it to "look
over its shoulder." It's the only
insect to be able to do so.
- Luber grasshoppers live mainly in the
deserts of Arizona, although a few are
sometimes found in Minnesota. Their tough
exoskeleton is so good at retaining their
internal moisture that often after they die
they do not rot.
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