Wednesday, August 4, 2010

A genus of nocturnal moths

Dysgonia is a genus of moths. Two members of this genus can be found in the Maltese islands. 

The two species resemble each other and can be difficult to tell apart. They do not have common English names and as happens in such cases it is better to refer to them using their scientific names. Dysgonia algira has been called baħrija tar-riġnu in Maltese while the Dysgonia torrida is called baħrija tar-riġnu Afrikana

Both species can be found between June and October. The caterpillar of both species feed on bramble, willow trees, castor oil tree and pomegranate. The moth in the picture was photographed at Fiddien a couple of metres away from a willow tree on which I assume its caterpillar was living. 

Dysgonia algira is found around the Mediterranean, in Asia Minor, Syria and Mesopotamia. Dysgonia torrida is found in Spain, Portugal, Sicily, Italy, Greece, Morocco, Egypt, Asia Minor and India.

The genus Dysgonia belongs to the family Noctuidae which is sometimes referred to as the owlet moths. This is a large family of mostly drab-coloured moths, although some have brightly coloured hindwings. The family has more that 35,000 known species. About 1,450 are found in Europe of which about 135 species are found in the Maltese islands.

Most of these species are nocturnal and are often attracted to lights as well as to sugar and nectar-rich flowers. Many are able to avoid bats as they have organs in their ears which are stimulated by the echolocation sounds made by bats. This causes their wing muscles to go into spasms and the moths start to fly erratically thus evading the bats.

Several species have caterpillars that live in the soil and are agricultural pests. These often feed at night and during the day they rest in the soil or in a crevice in its food plant. 

This article was published in The Times on 27.07.10

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