A fly to keep away pests

The tachinids are flies belonging to a family known scientifically as Tachinidae.

The tachinid family consists of over 8,200 species. About 1,600 species are found in the Palearctic region, which is the faunistic regionl region in which we live. Just over forty species have been recorded in the Maltese Islands.

The first list of Maltese tachinids can be found in a book on Italian flies written in 1859 by Camillo Róndani, an Italian entomologist noted for his interest in flies.

The author recorded nineteen species of tachinid flies from the Maltese islands. At the time Italian naturalists included the Maltese islands as part of the Italian territory and listed species of  Maltese plants and animals as part of  Italy’s flora and fauna.

Of the nineteen species recorded by Róndani, six are no longer found in the Maltese islands. The disappearance of these species could be due to natural causes but it is likely that it is a result of human activities such as the degradation and destruction of the Maltese countryside. Biodiversity is also reduced by the use of pesticides as well as the burning of vegetation during the summer months.

Fischeria bicolour, the species in the photo, is a member of the Tachinid family. It does not have a common name and is often overlooked by non-naturalists. This species is normally seen on vertical rock faces and on walls.

The larvae of all known tachinids are parasitoids. They live mainly in other insects especially on bees, wasps and ants eventually killing their host.

Tachinids play a major role in the natural control of other species including pests. Some species are used in biological pest control. Many species from around the world have been introduced into North America to control pests.

As adults, tachinid flies are not parasitic. During the adult stage many species do not feed at all but some visit flowers in search of pollen and nectar while others feed on decaying matter. 

This article was published in the Times on 27 November 2013.