Dragonfly Notes

by Carl Strang

Today I want to share some observations of dragonflies from last week. It was, as you know, stinking hot all week, reaching 100F on Thursday and Friday. In the late morning on Friday, with the temperature in the mid-90’s, I was taking an early lunchtime walk along the May’s Lake shore. I noticed that the black saddlebags all were flying in an unusual position.

All had this peculiar abdomen dip, which they held as they flew.

It was reminiscent of the obelisk posture, shown by a perched dragonfly pointing its abdomen up at the sun. This is thought to reduce overheating in the insect’s body. I wonder if the saddlebags, in that extreme heat, likewise were reducing the size of their abdomens’ exposure profile. They were among the largest dragonflies I saw that day, which further might increase their danger of overheating.

Earlier in the week I was walking through one of Mayslake Forest Preserve’s prairies when I saw a common pondhawk carrying a relatively large prey to a perch.

It had caught a smaller dragonfly, a female eastern amberwing.

Female and immature male pondhawks have such perfect grass-green camouflage that they are practically invisible when perched in prairies and meadows. They are sit-and-wait predators, zooming out to catch passing insects. This predation on another dragonfly is not so rare. I once saw one catch a calico pennant, a dragonfly larger than the amberwing.

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