Environmental effects on wing shape and wing size of Argia sedula (Odonata: Coenagrionidae)


Well-adapted flight morphology must allow for efficient behavioral activities. Wing shape has been shown in a variety of species to be influenced by environmental conditions. Analysis of wing shape using geometric morphometrics provides a visualization of wing shape variations. This study examined the effects of varied environments on wing shape and wing size of the damselfly Argia sedula in central Texas. Comparisons were made (1) between populations collected early in the flight season versus those collected late in the flight season; (2) between populations collected at different locations, and (3) among populations collected from the same locations during several annual flight seasons. We found widespread differences in both wing shape and body size in males and females among most environments examined. Male and female damselflies collected early varied significantly from those collected late in the flight season for all locations and years sampled. Damselflies emerging early in the flight season were significantly larger than those emerging late in the season. Significant differences in wing shape and size occurred in comparisons of male and female damselflies collected in different years at the same location. In comparing damselflies collected at different locations, neither females nor males varied significantly in wing shape. Size varied in only one male comparison between locations. Our results suggest that differences in seasonal and year-to-year environmental conditions, but not geographical location, frequently influence wing shape and wing size in A. sedula, and quite possibly in other damselfly species.

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