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Don't Bug Me: Canoe Country Insects by Steve Volkening

[PHOTO: Dragonfly on leaf]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.

[PHOTO: Illustration of mayfly]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.


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.


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.3m Ultrathon Insect Repellent Spray 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.


       --article courtesy of BoundaryWatersMagazine

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