Twelve-spotted Skimmer dragonfly terminal appendages

Twelve-spotted Skimmer (Libellula pulchella) is a member of the Skimmer Family of dragonflies that is spotted during the summer months at many water bodies in the mid-Atlantic United States, such as the wetlands at Huntley Meadows Park (HMP).

Twelve-spotted Skimmers display sexual dimorphism; terminal appendages may be used to differentiate immature males from females.

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

The preceding individual is a young male, as indicated by the white partial pruinescence covering his abdomen. In contrast, the abdomen of the following mature male is completely white.

Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

Related Resources: Odonate Terminal Appendages.

Copyright © 2015 Walter Sanford. All rights reserved.


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