In Virginia, one of the very first insects to make an appearance in the New Year is the winter stonefly, Taeniopteryx. These flat, slender, and sprawling insects are grayish brown and measure 9.0 to 11.0 mm in length. They are also known by other appellations, such as willowflies and early black stoneflies.
Most of their lives are spent as larvae that nibble on aquatic vegetation and submerged debris as they crawl along coarsely pebbled and rocky bottoms of large streams and rivers. Beginning in late January or early February, the mature larvae leave their watery past behind for good and haul themselves up on nearby rocks and vegetation. The freshly emerged adults, having just escaped their larval exoskeletons, soon festoon boulders, logs, bridges, and nearby buildings by the dozens, even hundreds. They are most evident on warmer days, but are seldom noticed by passersby, save for naturalists on the lookout for signs of life after a long winter or anglers reading the latest hatch.
For me, the sudden appearance of these hardy insects serves as an annual reminder that winter is almost over and spring is on the way. This is welcome news to entomophiles living in the frosty and leafless eastern United States!
Many thanks to Boris Kondratieff of Colorado State University for helping me with the intricacies of winter stonefly identification.
©2009, A.V. Evans