Aug 08 2011
Three weeks ago I hiked along Hell Run down to Slippery Rock Creek and paused by the stream to eat lunch.
It was cooler by the creek so I stayed a while and watched the water striders patrolling the quiet pools. Eventually a dragonfly flew over the creek, then hovered above the riffles and began to bounce her tail in the moving water over and over again. It looked like she was riding a pogo stick.
What was this?
My bug knowledge is almost non-existent so I asked Chuck Tague and he put me in touch with Ben Coulter. Ben told me I saw the typical ovipositing behavior of a female spiketail. Though I couldn’t describe the bug well enough to identify the species, it was in the Cordulegaster genus.
Yes, the dragonfly was laying eggs.
To show you how strange this looked I found two videos on YouTube. The first, above, is a good illustration of the pogo-stick behavior even though the bug in the movie is not native to North America. (The golden-ringed dragonfly lives in Britain.)
The second, below, is an award-winning video I’m sure you’ll enjoy — and it shows dragonflies native to Pennsylvania.
David Moskowitz studied Tiger spiketail (Cordulegaster erronea) mating behavior by suspending fake female look-alikes from fishing poles to see if they could attract a mate. When the fake females did not bounce, the males were uninterested. When the “females” looked as if they were ovipositing, the males tried to mate with them. Notice how the male rushes over and grabs her!
Turn up your speakers; you’ll like the music. (Sorry about the ad a few seconds into it.)
And don’t miss David Moskowitz’ Bug Addiction website.
(videos from YouTube)