August, 2011

Rambur's Forktail

Garden ponds are often good habitat for some of our aquatic insects. Rambur's forktail (Ischnura ramburii) is a fairly common damselfly in the Austin area, as well as in much of the southern U.S. Many people think that damselflies are bright blue and, indeed, some species are. However, Rambur's forktail is much more varied, with four different color forms: one for males and three for females. Males are distinctive with their main body being light green, their abdomen (the thin "tail" part) yellow with black markings on top, and the tip of their tail bright turquoise blue. Females come in a version similar to males but with a blue body instead of the green, another form that is mostly dark olive green with white below, and the one shown above, which is mostly red.

Damselflies, like their bigger cousins, the dragonflies, are predators. Even though damselflies appear to be very delicate and do not zoom about very fast, they still do an admirable job of devouring smaller prey, such as mosquitoes, gnats, and even each other. If you look closely at what this individual is eating, it becomes apparent that there is a gruesome bit of cannibalism going on here. The bit that is being eaten is the tip of the abdomen of another Rambur's forktail.