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Monday, 28 August 2017

28-8-2017 VILLALONGA RESERVOIR, VALENCIA - BEAUTIFUL DEMOISELLE DAMSELFLY (Calopteryx virgo)


The beautiful demoiselle (Calopteryx virgo) is a species of damselfly belonging to the family Calopterygidae. It is found in Europe, North Africa, and Western Asia.[1] It is often found along fast-flowing waters.

Females can lay up to 300 eggs at a time on floating plants, such as water-crowfoot. Like the banded demoiselle, they often submerge underwater to do so, and the eggs hatch around 14 days later. The larvae are stick-shaped and have long legs. They develop over a period of two years in submerged vegetation, plant debris, or roots. They usually overwinter in mud or slime.

The larvae of the beautiful demoiselle develop over 10 to 12 stages, each of which ends with a moult. The body length varies and depends on environmental conditions. In the final stage (F-0-stage), larvae are 3.5–4.6 millimetres long and weigh about 4 milligrams, slightly smaller than those of the banded demoiselle. The larvae of the beautiful demoiselle can be recognized by the bristles of the gills on their abdomen.

The body of the larvae shows only a relatively small adjustment to the fast-flowing waters of their habitat. The body is not flattened, but it is very slim, and the legs are long and end with strong claws. Because they reside within the water, and mainly in quiet areas, the danger of being swept by the flow is relatively low. If this happens, they stretch out to grab onto passing vegetation or substrate.

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