Winter Flies

I love a good mystery.  Maybe that is part of the reason I chase bugs.

We have had some early winter weather.  For the last couple of weeks the daily high temperatures have been below freezing.  We had a little bit of snow, and never enough warmth to melt it.

Yesterday was different–the high temperature went up to slightly more than 50 degrees Fahrenheit.  While walking in the yard, I noticed some flies doing a little dance.  There might have been as many as two dozen all together, moving mostly vertically–up, then back down.


They are difficult to photograph, but I think I got four in this photo.

One landed on some grass and I got a better picture.


It’s a winter crane fly.  They are known to exhibit this mating behavior in late fall and winter. It is claimed that it is mostly males flying, then a female will occasionally fly in to mate.  Larva develop in decomposing vegetation.

So were they present in the snow and ice as adults, then encouraged to mate by the thaw?  Or were they pupae that emerged due to the warm temperature?  Why mate at this time of year?  It seems warmer temperatures would be better.  How long do the adults live?

Knowing the answers to those questions might just produce more questions.

About the roused bear

Nature photographer from central Iowa.
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