Naturespeak A naturalist's view of the world

June 13, 2011

Ebony Fliers

Filed under: Uncategorized — wykes @ 5:27 pm

The last bout of sultry pre-summer weather found me wandering about the spillway on the River Raisin dam at Tecumseh.  I wasn’t lost, but not sure what I was looking for either. On a hot day you seek the shade of the woods first and, after being driven from same by the mosquitoes, you seek the presence of water. On the second phase of my walk I ventured to the concrete outlet were the impounded waters of the river are set free.

Just down from this active tumbling flow, the Raisin takes a gentle bend to the west and enters into a shady wood. The sunny streamside immediately before this turning point is lined with willow trees and among the fluttering willow leaves were clusters of fluttering black wings. These turned out to be the reason I was there (although I didn’t know that beforehand). It’s funny how this happens when taking an aimless walk. To turn around a popular song phrase, I could say that “you don’t know what you’ve got till it’s found.” At any rate, those willows were hosting a cluster of very active Ebony Jewelwing damselflies.

Jewelwings are among, if not the, largest damselflies in the state (a blanket statement that saves me from actually looking up the figures). They are among the most beautiful without a doubt (members of a genus Calopteryx – meaning “beautiful wing”). Ebony Jewelwings are creatures of dappled sunlight. They move into and out of shade so their décor is designed for this environment.  Their broad black wings, metallic bodies, and active behavior make them stand out from the background.  In true damselfly character, these insects flutter about like butterflies and employ their papery wings in the courtship process as well.  This was the thing that called them to my attention.

One especially low hanging willow was the center of attention on this particular morning. The coal winged males would face off with prospective mates and hover in front of them like bugs on a stretchy string. By flaring all four wings, the male’s display emphasized the bouncy movement.  The females, with their white (stigma) spotted wings, would flutter back in return – or not (see above).  No flutter meant a complete lack of interest from the feminine side (apparently damselflies are related to people).  When not fluttering, the males would roost on lookout perches and chase each other around.

Successful males – those whose wooing attempts resulted in woo – would grab onto the female’s head using claspers located at the end of their abdomen. The females would bring their abdominal tip up to receive their “prize” from the male’s thorax and complete what is entomologically referred to as the “wheel formation.” As you can see below, this is a proper and fitting name. Once the sperm packet was transferred, the females broke loose and began to lay eggs.  They directed their efforts on a matte of fine exposed tree roots in the water just below the tree. Although I didn’t actually see this part, I know that each damsel was inserting her eggs into the stem below the waterline(“you don’t know what you’ve got till you read”).

Jewelwings rarely sit still for their portraits (see below), but upon closer examination their beauty does fade a bit. Up close, you can see their widely spaced eyes and rows of long stiff leg hairs. Damsels are gawky looking predators that take their prey on the wing and these hairs assist in that regard. They interlock to form a neat little basket when the legs are gathered together to scoop critters out of the air.

They also are equipped with good vision and the slightest movement will send them off. Jewelwings (in fact, all damsel and dragonflies) have the ability to turn their heads around to look straight into your eyes.  I was both the watcher and the watched on that hot June morning along the Raisin.



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