Survival of the Fittest?

He was engaging and informative – feeding our tour group piece after piece of the fascinating history of the people and landscape of the Wildcat Hills Landscape.  The first guest speaker on the 2014 Nebraska Natural Legacy Conference Field Trip to the Loess Hills was really fantastic.  But as I was listening to him, I was wandering around the outside of the group with my eyes (as they often are) scanning the ground, looking for something small and interesting.

…And that’s how I found this darkling beetle.  It was plodding steadily along through sparse vegetation with no apparent concern that it was readily visible to any predator passing by.  Before I knew it, I was lying flat on my belly with my camera, photographing this intriguing little creature (while still listening, of course, to the captivating speaker…).

Darkling beetle

Darkling beetle

Thanks to James Trager and Ted MacRae, I can tell you that not only is this a darkling beetle, it is one of about 263 described species of asidine darkling beetles in North America (Coleoptera: Tenebrionidae: Asidini).  I did some reading about asidine darkling beetles and came away with many more questions than answers – which happens every time I research any creature…  My biggest question was this: how do these beetles avoid getting eaten by every predator they encounter?

The beetles in the Asidini tribe are flightless, and supposedly rely on camouflage as a major defense strategy.  I don’t know about you, but this one doesn’t look to me as if it’s particularly well camouflaged, except maybe at night.  The other defense ascribed to asidine darkling beetles is that they resemble another group of darkling beetles that has a chemical defense strategy involving a nasty smelling substance that blisters the skin of humans (and probably other predators).

Mimicry is fine and good, but depends upon potential predators being familiar with the dangerous creature you resemble.  That seems like a long shot, given the number of predators running around – how many have had experience with nasty-smell-emitting darkling beetles?  Regardless, the slow flightless beetle I photographed seemed either supremely confident or blissfully ignorant as it trucked along, fully exposed to the world.  It sure didn’t look like it could outrun a hungry bird or other large predator, and it wasn’t making any obvious effort stay under cover as it moved around in the middle of the day.  Seriously, how the heck is this species still around?

Look, what do I know?  Maybe potential predators are well aware of the existence of the stinky blistering-chemical-emitting critters these asidine darkling beetles look like.  Maybe that awareness doesn’t come from from personal experience but instead is embedded deep in the DNA of those predators.  Doubtful?  Think about all the people you know who are deathly afraid of spiders or snakes, even though they’ve had no personal negative experience with them.

One way or another, there seem to be plenty of asidine darkling beetles lumbering through the world, and they’ve apparently been doing it for thousands of years.  They must be doing something right.  Good for them.

I wish them luck.

Frozen Bugs (and Beetles)

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 three kids had a great time ice skating on the pond over the holidays.

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

A frozen water boatman

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Another one

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?

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.

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.