On mild winter days you may wish to look closely at all the dark, little specks on the surface of the snow. Most of them will be bits of lichen, seeds or pieces of bark, but with luck you may find one or more of them moving. Active winter insects aren’t plentiful, but they do exist.
Scorpionflies are fairly common and can be recognized by their long beaks ending in visible mouthparts. (They get their name from one family of scorpionflies that possesses a scorpion-like tail.) Snow Scorpionflies belong to a family of small, flightless insects, of which there are two species in the Northeast. They only measure about 2/10’s of an inch, so careful scrutiny is necessary to spot one. Their dark color and an anti-freeze substance in their blood allows them to remain active to 21°F., during which time they feed on mosses. When startled, Snow Scorpionflies often jump up in the air and land with their legs crumpled up (see insert) looking even more like an inedible speck of dirt. It’s fairly easy to tell their gender, as female Snow Scorpionflies (photo) lack wings, and males have bristly wings adapted for grasping females.
Stoneflies spend the larval stage of their life in streams. When the larvae mature, they crawl out of the streams they grew up in, split their larval skins and emerge as winged adults, ready to mate. Stoneflies are unique among aquatic insects in that there are different species that emerge in all months of the year. Most species mature in warmer months, but some do so during warm spells in winter and there are two families (referred to as winter stoneflies) that emerge only at this time of year, perhaps because of the scarcity of predators.
Recently, perhaps due to the warm weather this past weekend, large numbers of stoneflies emerged. In places, the snowy banks of open streams were littered with half-inch adult stoneflies whose new skins were drying. This entomological exodus from the water typically takes place at night, to avoid being eaten by terrestrial insectivores and birds. After their adult skin dries, winter stoneflies can be seen crawling on top of the snow as they search for a mate.
In many species, male and females locate each other by tapping the tip of their abdomen upon the substrate, a process referred to as “drumming.” Any stoneflies in contact with that substrate will feel the vibrations of this drumming. Male and female drumming patterns are specific for each species and for each sex. Male stoneflies initiate drumming and females answer. This means of auditory communication is closely related to the “songs” of crickets, grasshoppers and katydids. The difference is that the sound waves of the terrestrial insect songs travel through the air and are loud enough for humans to hear, whereas the sound waves of stonefly drumming travels through a solid medium and is inaudible to us.
The diet of both Cedar and Bohemian Waxwings is primarily sugary fruits throughout most of year. Research shows that they can subsist on this diet exclusively for as many as 18 days. However, in winter when feeding on fruits, they also feed on buds and available insects. In warmer months, waxwings will fly out over water from exposed perches, much like flycatchers, and snatch emerging aquatic insects such as mosquitoes, midges, mayflies, caddisflies and dragonflies out of the air. They also glean for vegetation-borne insect prey, such as scale insects. At this time of year they are taking advantage of winter stonefly hatches over open streams. (photos: bohemian waxwing & stonefly)
In the Northeast, honeybees typically choose a protected site such as a hollow tree in which to build their hive. Harsh winters demand this protection. Infrequently you will see where an attempt has been made to survive the elements without anything to contain the heat that the honeybees produce by shivering, or to block the wind, snow or sleet. Inevitably, this far north, the colony does not survive the winter.
It seems early, especially with feet of snow still on the ground, to be seeing insects flying around, but some have actually been present all winter. An order of insects (Plecoptera) known as stoneflies spends its youth (one to four years) living in streams before emerging as winged adults. Some of these species, referred to as winter stoneflies, emerge from January through April, providing food for early-returning, insect-eating migrants, such as Eastern Phoebes, Tree Swallows and Red-winged Blackbirds. Stoneflies only live a few weeks, during which time they mate and lay eggs. Some do not feed, and others consume plant material. Because stoneflies are intolerant of polluted water, if you see one it’s a good indication that the water quality of the stream that it came from is excellent.
Backswimmers 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!