Friday, October 23, 2015
Aerial cannibals !
If you are at the beach you might look up and notice that an interesting migration of dragonflies is taking place just over your head. Dragonflies are heading south to escape the frozen north in considerable numbers and I watched many common green darners passing by at Caspersen beach, Venice, FL, on Oct. 21.
It may surprise you that relatively primitive insects such as dragonflies are capable of such long distance migration. They are extraordinary flyers but they apparently get hungry while flying and their appetites take a bizarre turn. This species is common around our farm ponds in VA so it is interesting to see where they go when they leave and are replaced by the equally large, but cool weather tolerant shadow darner.
I saw several twosomes of common green darner dragonflies writhing on the road and on closer inspection realized that one of the pair was eating the other! The dragonfly on top had its jaws embedded into the thorax of the victim. I knew that falcons often eat migrating dragonflies but did not realize that these predaceous insects could and would eat their own species.