Water Scorpion

Water Scorpion - Nepa cinerea

Water bug, belonging to the Cryptocerata group, which as its name, which literally means "hidden horns" suggests, keep their antennae hidden in pits or furrows under their head so that they are protected under the water.

Reddish-brown in colour, its wings are perfectly developed but they do not seem much adapted for flying because the flight muscles have regressed and are poorly developed.

Like all the insects in the family, Nepa cinerea has a long, 10-12mm breathing tube so that it can replenish its air supply even when it is under water. This respiratory siphon makes the bug look quite threatening, and probably gave it its common name of water scorpion.

Its flat body, up to 23 mm long and legs lacking in swimming hairs suggest that this insect is not a good swimmer, and in fact it prefers shallow waters and moves by crawling.

It often hides on the bottom or among subm

erged water plants, waiting for its prey - insects, tadpoles and small fish which it catches with its front raptorial legs. Widespread in central Europe, the Water Scorpion is common in stagnant and flowing waters.

The eggs, laid on plants on the water surface, remain underwater but have 6-8 threads that stick out of the water and seem to have a respiratory function.

As they develop, the immature stages, at first similar to bugs, acquire the characteristic respiratory siphon which reaches its final length after the 5th moult in late summer - early autumn.