Predaceous Diving Beetles Remaining Active
While meadows and fields are experiencing a sharp decline in insect life at this time of year, one habitat where insects remain active in the fall and often through the winter is ponds. Among the year-round active pond invertebrates are Predaceous Diving Beetles, which can still be observed as they row through the water, intermittently surfacing to thrust their abdomen above the water line in order to procure a bubble of air from which they breathe. Their middle and hind legs are fringed with long hairs, making them efficient at rowing through the water in search of prey or detritus to eat.
Predaceous Diving Beetles lay their eggs on and in plants above the waterline in early spring. When the eggs hatch, the larvae drop into the water. Mature larvae crawl out of the water to pupate in damp chambers on the shoreline. They emerge as adults and re-enter the water, where they remain active through the winter, under the ice. (Water Scavenger Beetles look a lot like Predaceous Diving Beetles, but they stroke first with one leg, then another, not simultaneously like Predaceous Diving Beetles, and they come to the surface of water head first to secure air.)
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