Mating Winter Crane Flies

2016 June 22

There are a number of species of small crane flies (about half an inch long) that are commonly found flying around even when the temperatures are barely above freezing. Here are some of them from November 5[1], 2015.

They can be mistaken for big mosquitos, but they aren’t. They don’t bite, and are somewhat attracted to our porch light (like these were).

These winter crane flies are most likely in the genus Trichocera, and in fact I’ve posted these before. So, why am I posting them again?

Because this time, I caught a pair of them mating!


We can see that the male has to be a bit of a contortionist. He’s mostly standing on her back, but his abdomen reaches around to get past her wings, and then curves up below to grab onto the tip of her abdomen.


As you might guess, this is a very vulnerable position, as neither of them can fly off very readily without spending time getting their wings and legs sorted out first. This is one good reason for them to wait until November to come out to mate – most of the things that might take the opportunity to snack on them are simply not around at this point. Spiders and predatory insects are either dead or hibernating, and the insectivorous birds headed south probably a month or two previously. So, even though the cold weather is probably a problem, it beats getting eaten.

After mating, the eggs get laid in moist locations rich in rotting material for the larvae to feed on. I see these around off and on during warmer days pretty much all winter, so the female might actually overwinter and lay her eggs at pretty much any time.

[1] Remember, remember, the 5th of November
The Gunpowder Treason and plot;
I see of no reason why Gunpowder Treason
Should ever be forgot.

Comments are closed.