Stoneflies

 

A Guide to Nature in Winter

Stokes Guide to Nature in Winter

This post is a part of the Nature In Winter series, examining the Stokes Nature Guide book of the same name.  Previous posts in this series:

Nature in Winter- Snow.

Nature in Winter- Winter Weeds.

Nature in Winter- Tracks in the Snow.

Nature in Winter- Bird Nests.

Insects usually overwinter by hiding in the soil, plants or trees.  Their eggs and larvae are sought by birds in various hiding places as good food in the cold months.  However, there are a small number of insects that are actually active during the winter outdoors- it can be easy to miss them.

I am not only talking about insects that come out on warm winter days.  There are species that have adapted to the cold as a survival strategy, coming out when many insect-eating bird species are far to the south in warmer climes.

One such insect is the stonefly.

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There is a park I walk in winter with a nearby creek where these insects are abundant on certain days in the middle of winter.  If you are there on the right days, you can see literally dozens of these insects crawling over the snow.  It is not a sight you expect to see if you are not looking for them!

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From Nature in Winter:

The stonefly is another insect that is often active in winter.  In fact some species of stonefly have adjusted their cycle to the exact opposite of those of other insects.   Their larvae, which live in streams, start feeding and growing in fall and early winter.  The adults emerge from the water in midwinter and mate on the shores; then the female lays her eggs back in the water.

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When they fly slowly through the are they appear like large gray mosquitoes.  But they are more often found crawling over rocks and snow at stream edges, where as adults they come to feed on algae.  These insects live only in clean rushing water, the larvae living and feeding under stones at the river’s edge.

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Insects that are active in winter produce a substance called glycerol in their bodies- think of it as antifreeze.  They move around as if it were a warm sunny day.

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Nature adapts to the various conditions of the earth in a startling variety of ways.  Nothing shows this more than insects crawling across the snow in the middle of winter.

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Further reading:

Insects in Winter (Wild Ones)

Winter Stoneflies Sure Are Supercool (Scientific American)