Dragonflies

Definition

Adult insects of the infraorder Anisoptera (order Odonata), characterized by large compound eyes that nearly meet at the top of the head, two pairs of elongated, membranous wings held horizontally at rest, and robust predatory habits in flight. Distinguished from damselflies (suborder Zygoptera) by broader bodies, eyes that are contiguous or broadly separated rather than widely spaced, and wings that are not folded together above the abdomen when perched. Larvae are aquatic, breathing through internal rectal gills, and are important apex predators in freshwater ecosystems.

Etymology

Middle English dragon + fly, from the imagined resemblance to a dragon in flight

Example

Aeshna cyanea, the southern hawker, patrols pond margins in temperate Europe, capturing mosquitoes and midges in mid-air with its spined legs before perching on vegetation to consume prey.

Synonyms

• Anisoptera

Related Terms

• Damselflies
• Odonata
• naiad
• compound eye
• Ommatidium
• hemimetabolous
• rectal gills
• aerial predator
• wetland indicator

Usage Notes

In strict technical usage, "dragonfly" refers specifically to Anisoptera, not to all Odonata; the vernacular term "dragonfly" is sometimes applied loosely to damselflies, but specialists maintain the distinction. The aquatic juvenile stage is properly termed "naiad" or "nymph," not "larva" in some traditional odonatological literature, though "larva" is widely accepted in general entomology.