Clubtails seem to be everywhere on our Littleton farm this week. These dragonflies, members of the family Gomphidae, are named for the bulge at the end on their long, narrow abdomen; in most species, the club is more prominent in males. Clubtails are also identified by their clear wings and widely spaced eyes; the latter trait, combined with their thin torso, makes them resemble damselflies.
More than 900 species of clubtails have been identified worldwide and about 90 species are found in North America. Most live along rivers and near ponds, where their nymphs burrow into the gravel or sediment of the stream floor or lake bottom; there they feed on the larvae of other aquatic insects and, in some species, may remain in the larval state for three years. Molting to adults during the warmer months, clubtails are not strong fliers; rather, they flit from one perch to the next, snaring small insects en route. Eggs are generally laid on aquatic vegetation but, in some species, may be deposited in mulch or leaf litter; in the latter case, the species may overwinter in the egg stage or the larvae may burrow into the rotting vegetation until they molt to adults in late spring or summer.
Our current invasion of clubtails will likely be short-lived. The first freeze in Metro Denver generally occurs during the first week of October, putting an end to the lives of most adult insects; of course, exceptions do occur (honeybees, ladybird beetles and cave crickets are but a few examples).