Mating Damselflies
Tue, Jun 30, 2009 at 7:39 PM
Do you really need an explanation?
ET
Columbia, MD

Ebony Jewelwings Mating

Dear ET,
Your photo of mating Ebony Jewelwings, Calopteryx maculata, is gorgeous, and we thought our readers would probably like additional information.  The male has the darker wings and the female has the white spot on the wings.  BugGuide has additional information on this eastern North American species, including “Not a strong flier: adults flutter, butterfly-like, a short distance when disturbed. They are easy to get close to as long as you approach slowly and don’t make any sudden movements. Ebony Jewelwings prefer sunny spots in the woods but usually perch only a minute or two before flitting to another nearby spot.”  BugGuide has sadly shied away from discussing the sexual behavior of the species.  We decided to try to include some of that and located a German site that explained  “The male sex organ is located at the front part of the abdomen. Damselflies commonly fly in pairs during mating. Damselfly adults use their hind legs, which are covered with hairs to capture prey as they fly. They hold the prey in their legs and devour it by chewing. Adults are usually found flying near plants, usually in irrigated rice fields during the daytime throughout the year. The damselfly’s mating pattern is unusual. The male deposits sperm by bending the abdomen forward and then clasping the female behind the head with its claspers on the tip of his abdomen. The female then loops her abdomen forward and picks up the sperm from the male. The mating pairs are seen flying and clinging in tandem. “  And finally, just to shake things up a bit, we located a National Geographic online article entitled Damselfly Mating Game Turns Some Males Gay by James Owen. Owen writes:  “Disguises used by female damselflies to avoid unwanted sexual advances can cause males to seek out their own sex, a new study suggests. Belgian researchers investigated why male damselflies often try to mate with each other. The scientists say the reason could lie with females that adopt a range of appearances to throw potential mates off their scent. In an evolutionary battle of the sexes, males become attracted to a range of different looks, with some actually preferring a more masculine appearance. “  Later in the article, this is nicely explained.  Owen continues with the following conclusions of the Belgian team:  “Van Gossum, the study author, says most researchers agree such polymorphism most likely results from sexual conflict, with females evolving traits to avoid excessive harassment. While plenty of sex might suit male damselflies, this isn’t the case for females. Joan Roughgarden is a professor of biological sciences at Stanford University in California. She writes, ‘Copulation ranges from over one hour to over six hours, averaging three hours. While a long copulation might seem like great fun, this can waste a whole day and be too much of a good thing, especially if carried out day after day over a life span that is only a few days long.  Roughgarden adds that female damselflies collect all the sperm they need to reproduce from a single mating.”  Some of our readers will be comforted to know that the image that you submitted depicts a traditional male/female coupling.

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