Yesterday I noticed several of these midland clubtail dragonflies (Gomphus fraternus, Gomphidae) near the River Raisin in southeast Michigan. This species is concentrated around the Great Lakes and adults only appear for a few weeks in and around June.
Clubtails get their name from their obvious clubbed tails, but this feature isn’t present in all taxa (Triplehorn and Johnson 2005). More subtle features of the eyes, mouthparts, and wings are also used to identify members of this family.
Dragonfly larvae (naiads) spend their time at the bottom of rivers and lakes ambushing other aquatic insects. As they grow they may molt 9-17 times before leaving the water to molt into adults (Triplehorn and Johnson 2005).
Although the adults fly rather well, they seldom stray far from their aquatic nurseries (Triplehorn and Johnson 2005). They continue the predaceous feeding habits of naiads, capturing other flying insects and often eating them in flight. They’re considered very beneficial to humans since both the larvae and adults consume large numbers of insect pests, including mosquitoes (Triplehorn and Johnson 2005).
Triplehorn, C.A. and N.F. Johnson. 2005. Borror and DeLong’s Introduction to the Study of Insects. Seventh Edition. Thomson Brooks/Cole, Belmont, CA.