Archive | 12:00 pm

Frog Tongues, Vader Masks, and Dragonfly Nymphs

4 Mar
The extended spoon-shaped labium of a libellulid dragonfly nymph.

The extended spoon-shaped labium of a libellulid dragonfly nymph.

One of my favorite examples of weird insect anatomy are the strange mouthparts of the aquatic nymphs of dragonflies and damselflies.  A close look at the faces of these creatures reveals large hinged structure folded back under the head.  In the case of the nymphs of Libellulidae, this structure actually curves up and wraps around the face, very much like a Darth Vader style mask.  What are these structures?

Ventral side of libellulid nymph.

Ventral side of libellulid dragonfly nymph, showing the spoon-shaped labial mask.

All Odonata larvae have a prehensile labium, sometimes called a labial mask, which folds under the head and thorax.  This lower lip is capable of extending rapidly forward, striking prey before they can react.  Hooks on the ends snag the prey and draw it back to the mandibles.  All in all, the feature is reminiscent of a frog tongue snatching flies.

Ventral side of aeshnid nymph.

Ventral side of aeshnid dragonfly nymph, showing the flat, blunt labial mask.