Dragonflies

Pronunciation

How to pronounce Anisoptera: /ˌænɪˈsɒptərə/

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Summary

Dragonflies, belonging to the suborder Anisoptera, are agile fliers known for their striking appearance and predatory habits both in their nymphal and adult stages. They inhabit diverse aquatic environments and have complex reproductive behaviors and ecological roles.

Physical Characteristics

Dragonflies are characterized by a pair of large, multifaceted, compound eyes, two pairs of strong, transparent wings, and an elongated body. Many species exhibit brilliant iridescent or metallic colors produced by structural coloration.

Identification Tips

Dragonflies can be distinguished from damselflies by their larger size and the fact that their wings are typically held flat and away from the body while at rest, whereas damselflies fold their wings along or above their abdomen.

Habitat

Dragonflies predominantly inhabit areas near water, including still, slow-moving, and swift-moving bodies of freshwater or brackish water. Some species may be found quite a distance from water while seeking suitable perch sites or during feeding.

Distribution

Dragonflies are found on every continent except Antarctica, with a high concentration in tropical regions. There are around 3,000 species worldwide, including approximately 325 species in North America.

Diet

Both the nymphal stage (naiads) and adult dragonflies are carnivorous. Nymphs primarily feed on aquatic invertebrates such as mosquito larvae, while adults prey on a wide range of insects including midges, butterflies, and smaller dragonflies.

Life Cycle

Dragonflies undergo hemimetabolous (incomplete) metamorphosis, spending the majority of their lives as nymphs (naiads) in aquatic environments before emerging as adults. The nymphs undergo a series of molts before transforming into adults, a process that generally occurs at night.

Reproduction

Mating involves complex behaviors where the male captures the female and the pair assumes a 'heart' or 'wheel' posture. Females then lay eggs either by darting over water or inserting them into plant tissue, depending on the species.

Predators

Dragonflies face predation from a range of birds including kestrels, merlins, and swallows, as well as water predators like newts, frogs, and fish for their nymph stages.

Conservation Status

Many dragonfly species are threatened due to habitat loss, particularly the destruction of wetland habitats, pollution, and climate change.

Ecosystem Role

Dragonflies play a key role in controlling insect populations, both as nymphs that feed on aquatic invertebrates and as adults that prey on insects in the air.

Economic Impact

Dragonflies can be considered beneficial as they contribute to natural pest control, particularly in rice agriculture by preying on pest insects.

Cultural Significance

In various cultures, dragonflies symbolize courage and happiness, and they are often depicted in art and literature. In Japan, they are admired symbols associated with strength and rebirth.

Evolution

The infraorder Anisoptera first appeared during the Early Jurassic, evolving from ancestral groups that exhibited different wing structures. Some ancient relatives, like the Meganisoptera, were significantly larger than modern species but are now extinct.

Similar Taxa

• Damselflies (Zygoptera)

Misconceptions

Common misconceptions include the belief that dragonflies can sting or bite humans, due to their predatory nature; in fact, they do not possess a sting and are harmless to humans.

Tags

• Dragonflies
• Insects
• Odonata
• Ecosystems
• Biodiversity