Saturday, January 9, 2016

Eastern Forktail

On 31 May 2015, I drove over to nearby Circle Lake. My goal was Eastern Forktails. Despite these damselflies’ being abundant in Rice County, I lacked decent photographs. I discovered my quarry. Forktails were thick along the roadsides. Beatonwrites that all ages of Eastern Forktails perch low on vegetation around the edges of ponds and lakes. This first photo shows what I assumed to be a male Eastern Forktail. Note the double, azure notches along the edge of the end of its abdomen. Note also the green sides of thorax. 
This damselfly acted oddly. It raised its abdomen and then curled it below its wings. This behavior is described by Paulsonfor female Eastern Forktails’ attempting to discourage males after the females have mated. Most females mate only once, after which they repel all other dragonflies. What I presumed to be a male may be an andromorph female
On the other hand, these photos may show some sort of maintenance behavior, allowing the damsel to clean his wings and abdomen. The sides of the thorax seem to be too bright for an andromorph. Usually andromorphs show pale, greenish-blue thorax sides (Lam). Scott King assures me this is, in fact, a male Eastern Forktail transferring sperm from his abdomen tip. Males store their sperm in a pouch under their thorax. Later, females attach to the pouch to fertilize their eggs.
Among the male forktails, I found a few reddish, immature females. These forms are harder to identify than the males. Note the thin black thoracic stripe and the black abdomen tip. Finally I encountered a few adult females. These damsels become quite pruinose (the blueish color covering its body). Identification marks include the complete blue thoracic stripes and the dark color on the upper half of the eye. Females are more likely than males to feed on other damselflies (Paulson).

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