The Aeshnidae, also called aeshnids, hawkers, or darners, is a family of dragonflies (suborder Anisoptera). The family includes the largest dragonflies found in North America and Europe.

Description

There are 41 North American species in 11 genera in this family. Most European species belong to Aeshna. Their American name "darner" stems from the female abdomens looking like a sewing needle, as they cut into plant stem when they lay their eggs through the ovipositor. ^[1]

The adults spend large amounts of time in the air and seem to fly tirelessly with their four large and powerful wings. They can fly forwards or backwards or hover like a helicopter. The wings are always extended horizontally. ^[1]

Their abdomens are long and thin. Most are colored blue and or green, with black and occasionally yellow. Their large, hemispherical, compound eyes touch in the midline and nearly cover their heads. They have an extremely good sight, and are voracious insect predators, using their sharp, biting mouthparts. ^[1]

The larvae ( nymphs or naiads) are generally slender compared to those of other families, with a long and flat extensible lower lip (labium).

The dragonflies mate in flight. The eggs are deposited in water or close by.

Etymology

The name may have resulted from a printer's error in spelling the Greek Aechma, "a spear". ^[1] The spelling Aeschnidae has been intermittently used over a period of time, but is now abandoned for the original name Aeshnidae. However, derived genus names (such as Rhionaeschna) retain the 'sch' spelling, as this is how they were first cited.

Taxonomy

In 1999, a proposal was made to split this family into Aeshnidae and Telephlebiidae ^[2]; as of October 2022, the World Odonata List compiled by The Slater Museum of Natural History considers them to be one family, under the name Aeshnidae. ^[3]

Distribution

Aeshnids are distributed worldwide; common worldwide or nearly worldwide genera are Aeshna and Anax. The African Anax tristis has a wingspan over 125 mm, making it one of the world's largest known dragonflies. ^[4]

Feeding Niches

In their aquatic larval (nymph) form, Aeshnidae are predators like all families of dragonflies. Aeshnidae, unlike some other families, are active predators and are found in still waters where they can actively pursue their prey. ^[5] In the later instars of their aquatic form, they can even eat small fish and tadpoles. ^{[5] [6]}

In their mature form, Aeshnidae can "eat many types of flying insects, such as flies, gnats, moths, butterflies, mayflies, damselflies, mosquitoes, and even other smaller dragonflies." ^[6]

References