Southern Damselfly
Coenagrion mercuriale - Damselflies and their close relatives the dragonflies are familiar waterside insects that hunt their prey on the wing. The drainage of ponds and marshes for agriculture and urban development-as well as an increase in the use of pesticides-threatens to wipe out these beautiful insects. The brilliantly colored southern damselfly frequents sluggish streams in lowland areas. In Britain it is restricted to a handful of counties such as Hampshire and Dorset in the south of the country. It is more widely distributed across northwestern Europe, from France and Germany southward to the Mediterranean. Southern damselflies are also known to exist in North Africa. Damselflies and dragonflies are familiar pond and streamside insects. Both have long, slender bodies, keen eyesight, and two pairs of wings. However, it is not difficult to tell the two insects apart. Damselflies are generally smaller and slimmer than their close relatives. In dragonflies the front wings and hind wings are of different shapes, with the hind wings being generally broader. In damselflies the wings are the same shape and taper into a narrow stalk just before they join the body. The two types of insect also alight and rest differently. Dragonflies always rest with their wings outspread, while damselflies perch with their wings only partly spread or held vertically over the body. The southern damselfly is a day-flying insect, and eyesight is important in all its activities. In many cases the eyes are so large that the head appears to consist of little else. However, damselfly eyes are not quite as dominant as those of the dragonfly and are set farther apart, making the front end of the animal look slightly hammer shaped. Since the head can swivel on the neck, the insects have almost 360-degree vision. Correspondingly, the senses of smell and touch are less well developed. The jaws are well equipped for biting and strongly toothed, a fact reflected in the name of the order: Odonata, meaning “toothed.” The damselfiles are harmless to humans, but feed on a variety of small insects such as mosquitoes and small flies, which they hunt down on the wing.
Reproduction
The reproductive lives of southern damselflies are closely connected with the water by which they live. The long, slender abdomen of the male is equipped with a pair of claspers situated near its rear tip. Just in front of the claspers are the openings of the male reproductive organs. When preparing to mate, the male transfers a drop of sperm from the opening by bending his abdomen forward and underneath to touch special receptacles near the front of the abdomen (just behind the last pair of walking legs). He then flies off to find a female to mate with and takes hold of her by the neck using his Jaspers. Mating is then achieved as the male perches holding the female while she bends her abdomen around under his body to touch her tip against his sperm-filled receptacles.
She then takes some sperm into her reproductive tract. After mating, the pair may fly around in the “tandem” position, with the male towing the female; this may often be observed in the spring. The female damselfly then dips the tip of her abdomen in the water to touch a suitable water plant. She makes a small cut with her egg-laying appendage and deposits her eggs in the plant tissue. The eggs hatch into an aquatic larvae known as nymphs. The larvae live in the water and breathe by means of gills carried on three tail projections at the tip of the abdomen. Like adults, the nymphs are carnivores and hunt for aquatic food, small worms, and the larvae of other insects. They have a specially adapted set of mouthparts called the mask. It is normally kept folded under the head, but can be extended with great speed, effectively spearing the victim on the terminal clawlike extensions.
Conflict over Conservation
Because of its rarity the southern damselfly has recently become the subject of government sponsored conservation efforts in Britain. Plans are in progress to allow swiftly flowing trout streams and the well drained land associated with them to deteriorate naturally into habitat that is more suitable for the endangered southern damselfly, namely slower running waters with boggy ground and soft banks. The proposals have given rise to conflict between the trout-fishing lobby and conservationists, but this has only served to highlight the needs of the southern damselfly. It is difficult to convince some people of the need to protect the damselfly, but slow progress is being made.
Southern damselfly – Coenagrion mercuriale
- Family: Coenagrionidae
- World population: Unknown
- Distribution: Southern Britain; northwestern Europe from France and Germany southward to the Mediterranean; North Africa
- Habitat: Slow-running streams and boggy ground
- Size: Length: 0.9-1.2 in (2.4-2.7 cm); wingspan: 1-1.4 in (2.5-3.5 cm)
- Form: Resembles small dragonfly; long, slim, brilliantly colored body; conspicuous eyes; 2 pairs of wings
- Diet: Adults feed on small insects, including mosquitoes; nymphs (larvae) feed on small aquatic animals such as other insect larvae
- Breeding: Males go in search of females in spring. After courtship and copulation eggs laid under water in water plants. Free-living larvae hatch and may feed for many weeks before emerging to molt as adult damselflies
- Related endangered species: Several, including Frey’s damselfly (Coenagrion hylas freyi)
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