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Posts tagged “Notonectidae

Backswimmers Active Under Ice

11-18-13  backswimmers under ice 061Backswimmers are insects classified as “true bugs” and belong to the order Hemiptera. Most Hemipterans are land dwelling, such as stink bugs and assassin bugs, but there are a few, such as water striders, water boatmen and backswimmers, that are aquatic. In the fall, when most insect hatches have ceased, backswimmers come into their own. While some hibernate at the bottom of ponds in winter, others remain active, sculling through the water with their oar-like hind legs that are covered with fine hairs, preying on all forms of life up to the size of a small fish. Thanks to bubbles of oxygen that they obtain from pockets of air just under the ice and carry around with them like mini aqua lungs, backswimmers can continue to stay below the surface of the water for several minutes. Like most aquatic insects, backswimmers supercool their bodies (produce antifreeze compounds called cryprotectants that allow their body fluid to go down to 26 to 19 degrees F. without freezing). Right now, when there’s a thin layer of ice on most ponds and no snow covering it, you might want to peer through the ice at the edge of the pond to see if you can locate any of these cold-hardy creatures. Just be sure you don’t fall in, as I did two seconds after this photograph was taken. My undying gratitude for those of you who have donated to Naturally Curious, as your support enabled me to replace both camera and lens!

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Backswimmers are aquatic insects that seek out prey as large as tadpoles and small fish. They row around ponds with their fringed hind legs and grasp prey with their front pair of legs. The piercing mouthparts that they use to kill their prey are also capable of giving humans who handle them carelessly a nasty bite (they are also known as “water wasps” for this reason).7-12-13  backswimmer 376 Because they spend most of their time on their back, their coloring is opposite that of most insects – backswimmers typically have a dark belly and a light-colored back, making them less conspicuous to predators (and prey) both above and beneath them. These tiny bugs can stay submerged for hours thanks to their ability to store air bubbles in two channels on their abdomen which are covered with inward-facing hairs. Backswimmers are often confused with Water Boatmen, which are not predaceous, do not bite, and swim “right side up.” Water Boatmen’s dark color and parallel lines on their backs help distinguish them from Backswimmers.