Beetles that Swim

Over time we've looked at how some animal species have adapted to live in the desert with little water and hot temperatures. Well, some wildlife have just chosen to live where there is water and cooler temperatures, despite being in the desert.

These spots are few and far between, but they do exist, like this spring out in the middle of a salt marsh. The surrounding soil is very salty, but the water temperature rarely rises above  15 degrees Celsius (about 60 degrees Fahrenheit). 

 
Here is one of the most common inhabitants, Dystiscus marginicollis, a predaceous diving beetle in the family Dytiscidae. As larvae, the long and skinny creatures are known as water tigers due to their predatory nature. 

As adults, they develop a hard exoskeleton and become oval shaped. They move through the water by using their legs as oars, moving their flattened hind legs in unison. They have a bubble of water stored under their wing covers to help them resurface, and they come to the surface tail first. As adults they can also fly around and find the perfect spring to live in.

To me, just the name predaceous diving beetle sounds a little scary. And learning that they are cannibalistic adds to their creepiness. So it took me some time to work up the courage to pick up a beetle to examine more carefully. After all, I didn't want to become part of its prey, even if it was just a nibble. 

After a few clumsy attempts, I finally managed to grasp the beetle and lift it up, making sure that its mouth was far from my skin. The photo doesn't do justice how wiggly the beetle was. It didn't really like me to hold it, and I didn't really like holding it, but I did it for you, the readers of this blog, for your personal edification. I'm sure you will feel intellectually stimulated after reading today's post. (Actually, I think you might be paranoid about these beetles if you see them, but that's really not my intent.)

It has six legs, just like any insect, along with two eyes, antennae, and mandible parts. Those mandible parts are what scared me. They're short but sharp, and anything that's sharp can really get your attention.

This particular species is widespread throughout North America. It has lots of close relatives; the family has about 475 species in North America. 

Apparently some species of these beetles are eaten fairly frequently in China, Thailand, and New Guinea, and are even raised for consumption. They reportedly taste like chicken. No, I'm kidding, the report I read said they taste rather bland. I have to admit that even though I sometimes do strange things, I did not taste this beetle for you. But if you want to taste one, let me know and we'll see if we can sort out something.

Closely related are the water scavenger beetles, in the family Hydrophilidae. Instead of using their legs like oars (both moving together), they use them like paddles (moving them alternately). Another difference is that when they come to the surface, they bring their head up first instead of their rear. 

Both predaceous diving beetles and water scavenger beetles will also eat carrion. So don't fall into a spring and die or you really will become dinner.