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.

Longhorns on the Prairie

One of the great things about prairies – and nature in general – is that there is way more to discover than I’ll ever have time for.  Especially within the world of invertebrates, there is no shortage of species to learn about, and every one of them has a fascinating story.  During the last two weeks, I’ve started paying attention to longhorned flower beetles, a group of species I’d noticed before while looking for bees.  Not surprisingly, once I started really looking at them, I discovered that there are multiple species and that they are much more common than I’d realized.

This longhorned beetle is likely Typocerus confluens, according to Ted MacRae.  There were a couple different (but similar) species around the day I took these photos.

This longhorned beetle is likely Typocerus confluens, according to Ted MacRae, but he said there are others that look enough like it he can’t tell for sure from a photograph.   The Nature Conservancy’s Platte River Prairies, Nebraska.

These beetles belong to the “flower longhorn” group of insects (family Cerambycidae, subfamily Lepturinae).  Adult flower longhorns are largely diurnal (active during the day) and feed upon a wide variety of wildflowers.  When I started looking for information on longhorns, I turned to Ted MacRae, an entomologist and author of the fantastic blog, “Beetles in the Bush“.

Ted helped me identify the species I’d been able to photograph around here, and gave me some good information on what longhorns are all about.  Ted, by the way, has documented at least 229 species and subspecies of longhorn beetles in Missouri.  That information made me feel better about being unable to identify my photographed beetles myself, but also strikingly ignorant about a very diverse group of insects I’d never really noticed before.  (Such is the way it usually goes with insects.)

Ted thought this was probably Typocerus octonotatus, a common Great Plains species of longhorned beetles.

Ted thought this was probably Typocerus octonotatus, a common Great Plains species of longhorned beetles.  You might think it looks just like the T. confluens in the earlier photo, but look more closely at the color pattern…  I know, right?!   Helzer Family Prairie, near Stockham, Nebraska.

Flower longhorn beetles are named for their habit of feeding on wildflowers as adults.  As larvae, on the other hand, most longhorn beetles are wood-borers.  That includes many (most?) members of the Typocerus genus – the genus of beetles I’ve been seeing.  However, Ted says the larvae of many Typocerus species in the Great Plains are actually subterranean root feeders on prairie grasses.  That, of course, seems a much more sensible strategy for insects in landscapes with only widely scattered woodland habitats.

Face on.

A longhorned beetle with a face full of pollen.

Now that I’ve started to pay attention to longhorned flower beetles, I’ll probably never ignore them again.  That’s both a blessing and a curse.  I love learning about new species, but it makes prairie hikes go more slowly because the more species I recognize, the more there is to see.  If this keeps up, it’ll take me all day to walk 100 yards!

Thanks to reading this post, your mind has also been infected with the visual image of longhorn flower beetles.  The next time you walk through a prairie, you’ll likely spot more than one.  (You might want to budget just a little more time for that prairie walk, by the way – sorry about that!)