Sunday, May 20, 2012

Dragonfly Appreciation

Male Common White Tail
I brought these dragonflies to the WOLF School field trip to the Butterfly House.  These "fighter pilots" of the insect world, capable of speeds over 35 mph, are threatening to some as they zip through the air.

I wanted to get them some good press and have asked Tana Pulles of our chapter to educate us about these Common Whitetails - Plathemis lydia.

It is that time of year again when we begin to see the fanciful flight of odonates (o-doe-nate).  Dragonflies and damselflies belong to a class of insects of the order Odonata.  Odonata means "toothed jaws" alluding to their nature as ferocious predators. This is true for their role both as a nymph in water and adult in the air. They are harmless to humans however and truly are our friends as they consume incredible amounts of mosquitoes, biting flies and other insect pests.

At this time, the Common Whitetail is the abundant species seen at Bull Creek.  Bob has photos both of a mature male and female. The male is the one with the white (priunose) abdomen.

Female Common White Tail
This male began as an egg laid in water.  After hatching, the larva spent a lot of its life living under water.  Then it underwent a metamorphosis process transforming while still a nymph, moved to the surface of the water climbing a rock or plant stem and when the time was right, cracked open and flexed out of that larval skin. When development was complete he emerged as the aerial insect we think of.

He may have flown up to a half mile away from the water breeding habitat to feed. It has now been one to two weeks since he flew from the water of his emergence and he intentionally has selected the still and quiet water areas of Bull Creek. His color indicates he is an adult and sexually mature.

Barb and Bob now have the pleasure of watching these adult males select, patrol (fly back and forth) and defend their territories typically along the shoreline - seeking their mates. Common Whitetail males are very aggressive toward other Common Whitetail males that may enter their territory and will raise their abdomen to display their white color as a warning. Thus the chase and pursuits are endless.
These dragonflies were kept chilled as the students passed them around in ziplock bags.  Once we were through, they warmed up for a minute and then took off quickly in search of lunch around the Botanical Center.

As we watch Odonates darting around above the water, gobbling up mosquitoes, gnats and other flying fodder, we should give them our silent thanks for the service, as well as for the free air show.

George Sims (Ozarks Chapter of MN) and other passionate odontologists from the Midwest have created a Yahoo Group that you can follow for local news.  
Use to report a new finding. 

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