Slaty Skimmer dragonfly terminal appendages

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

Slaty Skimmers display sexual dimorphism. Although mature males and females look different, immature males and females look similar. Terminal appendages may be used to differentiate immature males from females.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (female)

Female dragonflies have a pair of cerci (superior appendages) that have little or no function. (See a full-size version of the following image, without annotation.)

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (female)

Look closely at the full-size version of the preceding annotated image. Female Slaty Skimmers have a pair of flanges beneath their eighth abdominal segment (S8) that are used to scoop water when laying eggs (oviposition), hence the family name “Skimmer.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Immature male Slaty Skimmers and immature/adult female Slaty Skimmers are nearly identical in appearance except for their terminal appendages. (See a full-size version of the following image, without annotation.)

07 JUL 2014 | Huntley Meadows Park | Slaty Skimmer (immature male)

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”). (See a full-size version of the following image, without annotation.)

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (young male)

This individual is a young male, as indicated by the blue-black partial pruinescence covering his body. He has a slightly malformed wing that is more noticeable in the preceding side view and less noticeable in the following dorsal view.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (young male)

Black pruinescence that completely covers the body of following mature male Slaty Skimmer makes it look quite different from the immature male (shown above), other than its terminal appendages.

10 SEP 2014 | Huntley Meadows Park | Slaty Skimmer (mature male)

Digital scans by G & J Strickland:

• L. incesta female #1 (Slaty Skimmer) — lighter tan face
• L. incesta female #2 (Slaty Skimmer) — brown face
• L. incesta female #3 (Slaty Skimmer) — old female, very pruinose

Digital Dragonflies: presenting high-resolution digital scans of living dragonflies.

• Genus Libellula | Libellula incesta | Slaty Skimmer | male | top view
• Genus Libellula | Libellula incesta | Slaty Skimmer | male | side view

Related Resources: Odonate Terminal Appendages.

Copyright © 2015 Walter Sanford. All rights reserved.

Tags: cerci, claspers, epiproct, female, hemi-marsh, Huntley Meadows Park, immature male, Libellula incesta, malformed, mature male, pruinescence, sexual dimorphism, Skimmer Family, Slaty Skimmer dragonfly, terminal appendages, vernal pool, wildlife photography, young male