Water scorpions!

Welcome back from the holidays, and Happy New Year! As we get further on into winter (well, assuming these unusual 60-70 degree highs that central Oklahoma has been having don’t last!), it’s only natural that our thoughts turn to summer activities such as swimming, or, say, collecting aquatic insects.

My first experience with collecting aquatic insects was during a summer class at a central Oklahoma university. I enrolled in an Aquatic Entomology class, taught by my favorite professor, and proceeded to go on several collection field trips. During one of these trips, I caught a curious-looking creature in my net that at first glance appeared to be a blade of dead grass. In fact, I very nearly plucked it out of my net and flung it back in the water. But upon more careful examination, I saw that it was actually an insect that looked like this:

http://en.wikipedia.org/wiki/File:Ranatra_chinensis.jpg

When we returned to the lab after our trip, I was excited to figure out the classification of the insect. It turned out that it was a water scorpion, in the genus Ranatra, from the family Nepidae, and in the order Hemiptera. Despite the name, this insect won’t hurt you – it only resembles a scorpion and does not have a stinger. The water scorpion has front legs that are raptorial, or folded in a praying-mantis sort of way. It also has two tubes that form a siphon on the end of the abdomen. When the water scorpion is in the water, the tubes curl up towards the water surface, taking in air to breathe. It’s as though the insect “snorkels” from its abdomen.

http://en.wikipedia.org/wiki/Nepidae

The water scorpion that I found was barely an inch long, so it can only hold tiny invertebrates in its front legs to eat. Sometimes the larger ones will eat tadpoles and very small fish as well, but they’re not terribly intimidating to us. However, if you were around the shores of the U.K. about 330 million years ago, you would probably beg to differ. According to an article in the National Geographic News, the tracks of a 5-foot giant water scorpion were found in the Scotland area in 2005.

If you’d like to read more about this enormous water scorpion, here is a link to the article:

http://news.nationalgeographic.com/news/2005/11/1130_051130_giant_scorpion.html