Calopteryx exul

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Glittering demoiselle (Calopteryx exul) is an endangered damselfly in the Calopterygidae family. It is native to North Africa, living only in Algeria, Morocco and Tunisia, with the largest populations in northeast Algeria. It tends to occur in rivers that flow fast and are shallow, with little shade and few plants.

The insect can reach about 50 mm in length. Its wings are unbanded in both sexes, but the males have a blue shine on their wing veins when the sun hits them. Males are territorial and guard the plants where females lay eggs.

Calopteryx exul has two generations per year: a longer one from May to July and a shorter one from September to October. They can disperse up to about 5 km to find better habitat. Adults hunt by ambush and often roost together at night.

Females lay eggs on floating leaves of a few plants, including Typha angustifolia, Paspalum distichum and Potamogeton nodosus. The larvae are about 22 mm long, with simple eyes and many bristles, and are yellow-brown.

Rivers face threats from pollution and human activity. Because this species relies on only a few host plants for reproduction, protecting those plants helps support populations. Drought, which lowers water levels and flow, can lead to local extinctions.