On an early December day, when temperature hovered around 40 degrees in a leafless Draper Twin Lake Park, a loose swarm of flying insects danced in the low afternoon sunlight. Instead of flying like most swarming insects, in a tumbling horizontal cloud, these small insects, about 1/4 to 1/2 inch long and very delicate, fluttered vertically near the ground, their tiny wings just a blur among the dry and shriveled remains of plants.
What sort of insect flies in December? Finally, one of these chill-hardy small creatures landed on a desiccated Queen Anne’s Lace (Daucus carota). A little research revealed that these up-and-down dancers were Winter Crane Flies (family Trichoceridae), a not-too-distant relative of the larger crane flies (family Tipulidae) seen in the summer months.
According to the Field Station website of the University of Wisconsin Milwaukee, it seems that these bobbing insects are males, probably doing a mating dance, luring out any recently-hatched female who might be interested. She will lay her eggs in a damp area – inside a a cave, under leaf litter or inside a hollow log like this one.
Most sources believe that adult winter crane flies don’t bother to eat. After all, winter doesn’t offer much food! But when the larvae hatch from those eggs, they forage on decaying plant matter until ready to pupate and emerge during a winter thaw or on a cold day in the very early spring. So you might keep an eye out for a few of these hardy Winter Crane Flies walking on the snow surface on a warm-ish winter day.
If winter insects intrigue you or your children, the Clinton River Watershed Council (CRWC) is hosting Bug ID Training on Thursday, January 11, from 6-7 pm. A few weeks later you can put your new ID skills to use at the CRWC Winter Stonefly Search on Saturday, January 20 from 9 am – 2 pm (registration required). These aquatic insect naiads can’t tolerate pollution because they require well-oxygenated water to survive. Finding them in a stream, therefore, is great sign of water quality. So if you have a future entomologist in your family or are just curious about the health of our rivers and streams, call CRWC (248-601-0606) or email (firstname.lastname@example.org) to register for either event. Click the link above for more details about these great opportunities. Thanks to Clinton River Watershed Council for monitoring the health of our water!