My family and I spent some time exploring the frozen pond/wetland at our prairie during the holiday break. We even got a couple days of great ice skating weather.
My kids had a great time ice skating on the pond over the holidays.
While we were on the ice, we found some great patterns (see earlier post), but we also found quite a few frozen insects. In particular, there seemed to be two species of insects – one bug and one beetle – encased in ice. The bug was a species of Corixidae, or water boatman. Its name comes from the fact that two of its legs are extra long and sport hairs that make the legs look and function like the oars on a boat. Water boatmen suck the juices from algae and plants through their long straw-like beak and are common inhabitants of just about any freshwater body around here. They are also frequently seen in the ice when those water bodies freeze up in the winter. Apparently, water boatmen can survive freezing and just start swimming again when the ice thaws. A pretty neat trick for an aquatic bug that lives in a temperate climate.
A frozen water boatman
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Another one
We had a two day period over the holidays during which the temperature briefly climbed up to about 60 degrees (Fahrenheit). The warmth didn’t last long enough to spell an end to our ice skating, but did melt some of ice along the edges of the pond. Apparently, the warm temperatures also encouraged a number of individuals of one particular beetle species to go exploring. Unfortunately, it appears quite a few of those beetles wandered out onto the ice and didn’t make it back. We didn’t see any of them on the ice before the warm spell, but found lots of them afterward.
Here’s one of the beetles that froze after (apparently) getting caught out on the ice after a warm day. I’m hoping one of my entomologically-inclined friends can help me out with identification and/or natural history info?
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This beetle apparently got flipped over before freezing.
I was curious to know whether those frozen beetles could do the same thaw-out-and-re-energize trick as the water boatmen, so I broke off a chunk of ice containing a frozen beetle and brought it home to thaw it. The beetle has been thawed out for more than a week now, and hasn’t moved, so I’m pretty sure it’s dead… The next question is: where were those beetles staying during the very cold weather earlier this winter, and how did they prevent themselves from freezing to death then?
Always more questions…
For more information on how water boatmen and other creatures weather the winter, see this earlier post from 2011.
The Prairie Ecologist 
That’s definitely an aquatic beetle-the hairs on it’s legs are for swimming. When it’s a big aquatic beetle, 9 times outta 10 it’s either a dytiscidae or hydrophilidae.
Fascinating post and photos. I had no idea the frozen boatman could revive once the water warmed again.
It is a hydrophilidae
Thanks Bill! Any idea why it was there that day (and not, apparently, the previous day?) Or why it wouldn’t be able to survive being frozen? Or where it typically would spend time during freezing temps?
I don’t know if any beetles have antifreeze, but it’s possible. I wonder if exposure to air when frozen causes them to ‘freezer burn’? The second boatman looks like a dried up old steak in the freezer… maybe one completely trapped in ice would survive?
Many beetles (and water boatmen) capture an air bubble to breath from-they frequently have to surface to exchange it with oxygen-rich air. I suspect that’s what caused them to get captured at the surface when it melted-respiration increased and they came up for air and got on top of the ice. I would assume they’d get down in the detritus to overwinter but don’t know…
This is so cool! Do you mind if I borrow one of your water boatman photos to post on my blog, giving you full credit for the image? I want to borrow it specifically so I can direct people to this post because it’s super cool – and I’ll be directing people here regardless of whether you’ll let me borrow a photo or not, because it’s just that cool. Wow, what an amazing thing to see! Seems so odd… Makes me wonder if the pond froze very quickly and trapped some things coming to the surface.
Sure! Glad you enjoyed it.
Awesome. Thanks!
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Great photo of the Boatman and interesting text too.
Looks like Tropisternus lateralis to me. Check the Bugguide page: http://bugguide.net/node/view/112211
Thanks Ken! That does look pretty good…
Fascinating post! Perhaps you’ve already read Bernd Heinrich’s “Winter World” but just in case you haven’t it’s a great resource for understanding how critters survive the winter.
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