Dragonfly terminal appendages (male, female)

“…as indicated by its terminal appendages” is a stock phrase used in many, if not most, of my dragonfly-related posts. This post will answer two questions:

  1. What are terminal appendages?
  2. Why are terminal appendages important field markers in dragonfly identification?

Let’s begin by answering the first question.

Male terminal appendages

All 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”). Male dragonfly terminal appendages don’t look exactly the same for all species of dragonflies, but their function is identical.

Painted Skimmer dragonfly (male)

06 JUN 2014 | Huntley Meadows Park | Painted Skimmer (male)

Can you identify the male’s three terminal appendages in the following photo? If necessary, then refer to the annotated image (shown above).

Painted Skimmer dragonfly (male)

23 MAY 2014 | Huntley Meadows Park | Painted Skimmer (male)

Female terminal appendages

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

Painted Skimmer dragonfly (female)

23 MAY 2014 | Huntley Meadows Park | Painted Skimmer (female)

Can you identify the female’s two terminal appendages in the following photo? If necessary, then refer to the annotated image (shown above).

Painted Skimmer dragonfly (female)

23 MAY 2014 | Huntley Meadows Park | Painted Skimmer (female)

Composite image

Notice the differences between female- and male terminal appendages, as shown in the following composite image: female appendages are shown in the background photo; male appendages are shown in the inset photo. See a full-size version of the composite image for a clearer view of the side-by-side comparison of female/male terminal appendages. The difference is obvious, isn’t it?

Painted Skimmer dragonfly (female)

Composite image contrasting female/male terminal appendages.

Why are terminal appendages important field markers in dragonfly identification?

When you’re ready to move to the next level of dragonfly spotting (see “Step 2” of 5), from say the beginner level to the intermediate/advanced intermediate level, you must learn to identify terminal appendages in order to differentiate males and females of the same species.

It all comes down to sexual dimorphism: mature males and mature females are either identical/nearly identical in appearance; or mature males and mature females are different in appearance, especially their coloration.

  • For those species of dragonflies that do not display sexual dimorphism, males and females are nearly identical in appearance except for their terminal appendages. For example, the male and female Painted Skimmer dragonflies (Libellula semifasciata), shown above, look similar.
  • For many species that display sexual dimorphism, immature males appear similar to mature females. This is true for many members of the Skimmer Family of dragonflies, such as Great Blue Skimmer (Libellula vibrans) and Slaty Skimmer (Libellula incesta).

Related Resources:

Copyright © 2015 Walter Sanford. All rights reserved.

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10 Responses to “Dragonfly terminal appendages (male, female)”

  1. More terminal appendages | walter sanford's photoblog Says:

    […] Showcasing some of my digital photography and videography. « Terminal appendages (male, female) […]

  2. A sampler of male dragonfly claspers (Part 1) | walter sanford's photoblog Says:

    […] Terminal appendages (male, female) […]

  3. A sampler of male dragonfly claspers (Part 2) | walter sanford's photoblog Says:

    […] Terminal appendages (male, female) […]

  4. Is it spring yet? | walter sanford's photoblog Says:

    […] 20 MAY 2015 | Huntley Meadows Park | Painted Skimmer (male) […]

  5. Painted Skimmer dragonflies (females) | walter sanford's photoblog Says:

    […] of these individuals are female, as indicated by their terminal appendages. For those species of dragonflies that do not display sexual dimorphism, such as Painted Skimmer, […]

  6. Aperture versus Lightroom | walter sanford's photoblog Says:

    […] As a test, I decided to use both recipes, old and new, to edit the same image, in this case a male Painted Skimmer dragonfly (Libellula semifasciata) spotted on 20 May 2015 near a vernal pool in […]

  7. Painted Skimmer dragonfly (teneral male) | walter sanford's photoblog Says:

    […] individual is a teneral male, as indicated by its coloration and terminal appendages. Its faint wing spots will darken gradually during the next several days after […]

  8. Painted Skimmer dragonfly (female) | walter sanford's photoblog Says:

    […] A Painted Skimmer dragonfly (Libellula semifasciata) was spotted near a vernal pool in a remote location at Huntley Meadows Park. This individual is a female, as indicated by her terminal appendages. […]

  9. Painted Skimmer dragonflies (males) | walter sanford's photoblog Says:

    […] Several Painted Skimmer dragonflies (Libellula semifasciata) were spotted at a vernal pool in Huntley Meadows Park. All of these individuals are males, as indicated by their terminal appendages. […]

  10. Painted Skimmer dragonfly (teneral female) | walter sanford's photoblog Says:

    […] was spotted at a vernal pool in Huntley Meadows Park (HMP). This individual is a teneral female, as indicated by her terminal appendages and the tenuous appearance of […]

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