Saturday, April 18, 2009

Ants Hibernating through the Floods?

Tracking club was lovely today - the weather was nice, the birds were singing and there were more interesting track stations than we could fit into the morning. While I was wondering about looking for tracks that could become the tracking stations, I noticed numerous small ant holes. I've certainly seen ants out at the sand bar before, but hadn't really stopped to think about their seasons.

I think they hibernate during the winter time. I didn't notice their presence during the colder months and it appears that they are just getting started with their year now.

For a little while now some of us have been holding questions about what happens to small mammals during the winter floods. There are a number of places, like the tracking club sandbar, that get completely covered by the flood waters multiple times throughout the winter. There are deer mice, jumping mice (who also hibernate), shrews and moles in those areas. Do they climb vegetation, just die, move to higher land, swim, something else? If they die or move how long does it take to repopulate the area? For at least some of them it doesn't seem to take long for them to show up on the recently flooded landscape. While the water from one of the floods this winter was still receding we found numerous deer mouse tracks in the freshly deposited silk as well as a number of larger mammals. And I don't think it was too much longer before I noticed fresh mole activity.

But mammals are relatively big and mobile compared to ants. It would be a real stretch to expect ants to move to higher ground, though not too much of one to think they might climb a tree. However, if they are hibernating underground, what protects them from flooding? Perhaps they have chambers that manage to trap enough air during the flood or maybe they don't need much air while hibernating? Maybe like some insects, they are able to keep an air bubble around them in the water?

I did a little Internet searching on ants in floods and saw a lot of links about fire ants floating. There was also an abstract for an article about one species of ant that lived in bamboo and managed flood control by drinking water inside, then going outside and peeing. I didn't find anything about this sort of situation though.

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