Blue bottles

Bluebottle (Calliphora vicina)

The bluebottle is a common fly. It sometimes enters houses but in winter you are more likely to see it in the countryside especially on sunny days as it sunbathes in a sheltered place to warm up its body. 

It is slightly larger than the much common housefly and has a grey head and abdomen and a bright metallic blue abdomen. 

The body and legs are covered in short stiff hair which is not easily seen with the naked eye unless you manage to get very close to a sedentary fly.

The eggs are laid in decaying meat or other organic material on which the maggots can feed. The maggots are fully grown in a few days and when mature they move to a dry patch of soil and bury themselves below the surface to pupate. 

The cocoon takes from two to three weeks to metamorphose into an adult fly.

In autumn bluebottles visit the flowers of the carob tree. They are attracted to the flowers because of their strong smell of rotting vegetation and are important pollinators of this tree.

The bluebottle is known in Maltese as żarżura while the closely related greenbottle is known as dehbija tal-ħmieġ, These two names might have been coined by naturalists or they might have been used in the past but are not used anymore as the Maltese nowadays refer to most flies as dubbien without being aware of the various species that they meet in their everyday life.

These two species belong to a group of flies known as blow-flies. This name comes from the old English term for meat on which a fly had laid eggs, which was fly-blown. It is estimated that there are over 1,100 species of blowflies. Six of them are found n the Maltese islands. Blowflies are known carriers of disease including dysentery. 

This article was published in The Times on 26.01.11