Dragonflies and damselflies are large, conspicuous insects often found close to fresh water. The Order Odonata is divided into two suborders, the Anisoptera containing the dragonflies, and the Zygoptera containing the damselflies.
Insects in the order Odonata closely resemble the oldest flying insects known from fossils. These fossil 'dragonflies' were very large, with one species reaching 71 cm in wingspan.
Damselflies are similar to dragonflies, but the adults can be differentiated by the fact that the wings of most damselflies are held along, and parallel to, the body when at rest. Furthermore, the hindwing of the damselfly is essentially similar to the forewing, while the hindwing of the dragonfly broadens near the base, caudal to the connecting point at the body. Damselflies are also usually smaller, weaker fliers than dragonflies, and their eyes are separated.
Adult dragonflies are generally stout-bodied and when at rest spread their wings out to the sides. Damselflies are generally more delicate and hold their wings along their body when at rest.
The larval stages of the two suborders can be distinguished by the placement of the gills. Dragonfly larvae suck water into their abdomen and move it over their internal gills. Damselfly larvae have gills at the end of the body as three appendages. Like many insects, the larval and adult stages of dragonflies and damselflies differ in their shape and behaviour and use different habitats. Eggs are laid into, or close to, water. The larvae adopt an aquatic lifestyle, with only a few exceptions. The nymphs are carnivorous, feeding on daphnia, mosquito larvae, and various other small aquatic organisms.
The gills of damselfly nymphs are large and external, resembling three fins at the end of the abdomen. After progressing through up to twelve larval stages the larvae crawl out of the water. Their skin splits and the winged adults emerge. The adults are predators that often capture prey while flying. They eat flies, mosquitoes, and other small insects.
The adult stage has a pre-reproductive period that may last up to three weeks. At this stage, the colour of the wings and body may change and the adults may disperse from their emergence point. The reproductive phase may involve the establishment of territories by males, which are protected against other males of the same species.
Copulation involves the male grasping the female behind the head with appendages on his abdomen while she bends her abdomen underneath his thorax to recover a packet of sperm that he has placed there. Adults may be seen flying in this tandem position.
A damselfly landing (its wings are not yet parked over its back)
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