Tuesday, September 3, 2013

American Rubyspot

On Saturday, I found four American Rubyspot damselflies along the creek that feeds into Carleton College’s Lyman Lakes. Identity should be no problem here, although these damselflies, even the male above, were not as gorgeous as the first rubyspots I saw in 2011. Photographing a flying rubyspot proved to be difficult. The damselfly suddenly darted over the stream, but usually returning to its original perch. Notice that this male’s abdomen is wounded, perhaps from an encounter with a hungry bird. Purple Martins, other swallows, and flycatchers all find dragonflies to be tasty morsels.
I was so intent on catching the rubyspot in air, that I never saw the Eastern Forktail fly by in the upper right-hand corner of the center photo. Only when I got home behind my computer did I see the forktail. The male rubyspot’s red wing spots grow larger over time, and are largest on dominant males. Paulson suggests that these spots actually decrease the most dominant male’s hunting success.
The last picture is of a female American Rubyspot. These damselflies do not have courtship displays.  Dominant males simply seize approaching females (Paulson). Males may briefly guard their mates, but only copulate once with any individual female, who may mate with a second male.

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