EPOW Ecology Picture of the Week -- Beware the Ferocious Water Bug

Explanation: What a strange creature! There I was, idly flipping rocks in this forest wetland, and suddenly this wonderfully weird and bumpy creature the size of my thumb scooted out from beneath.

This is a giant water bug, sometimes called a "ferocious" water bug (they will bite!), of genus Abedus. This genus is known by its large size (more than 26 mm or about an inch long) ... and by the obvious and odd fact that the females lay their eggs onto the backs of the males, as shown here.

Aquatic entomologist Ken Cummins tells me that this egg-laying behavior has adaptive significance, in that egg survival is likely greater when defended by a "ferocious" male.

Interestingly, in the water bug family Belostomatidae, females of species of Abedus and Lethocerus lay their eggs on the backs of males, but species of Belostoma do not; they lay their eggs on vegetation and other surfaces in the water. Why the variation within the family? I don't know.

Think it's not really "ferocious?" Ken also tells me that there are many documented cases of water bugs taking fish. The bugs are also duly called toe biters. And some -- such as a truly giant species I discovered in the Congo of Africa -- can be monstrously huge. Watch where you wade!

Identifying this individual to species -- and there are 6 or 7 species of Abedus in North America -- takes microscopic work.

I found this critter in a magical, remote wetland on Kaibab National Forest, west of Flagstaff, Arizona, at about 2160 m (7100 feet) elevation in Ponderosa pine forest. Once photographed, I left him in peace. He'll have his flippered-legs full once those eggs start to hatch ...

Acknowledgment
My thanks to Dr. Ken Cummins for help with the identification. Special thanks to special friend Dick Holthausen for guiding me to these remote and amazing wetlands.

Information
Merritt, R. W., K. W. Cummins, and M. B. Berg. 2008. An introduction to the aquatic insects of North America. Fourth edition. Kendall/Hunt Pub. Co., Dubuque, Iowa. 1158 pp.

EPOW - Ecology Picture of the Week