House fly  (Musca domestica)

Very common and widespread (1).

The house fly is, perhaps, the most common and widespread animal in the world (3). It is a serious pest, which spreads many disease-causing pathogens including Salmonella, anthrax and polio (4). It is greyish in colour with four dark stripes along the back (4). Like all flies it has one pair of membranous 'true' wings; the second pair of wings are modified into drumstick-like appendages known as 'halteres', which are used in balance. The sponge-like mouthparts are adapted for feeding on liquids, and the reddish compound eyes are large (5).

This species is ubiquitous throughout Britain and is found in many parts of the world (3).

Occurs in a wide range of habitats, and is often associated with human activities (1); tends to breed in manure and decomposing material (3).

House flies contaminate food, and in developing countries are responsible for millions of infant deaths per year as a result of dehydration caused by diarrhoea (5).

House flies undergo 'complete metamorphosis'; the larvae (maggots) progress through three stages known as 'instars' before a pupal stage develops in which complex changes take place as the body of the maggot re-organises into the adult fly (4). Adults feed on rotting plant and animal matter and sugary liquids. They repeatedly salivate on food, ingest it and regurgitate it in order to pre-digest the food (4).

This species is not threatened. It is subject to control measures in some areas as it can be a serious pest (6).

Not relevant.

For more on invertebrates see Buglife, the invertebrate conservation trust:
http://www.buglife.org.uk/

• Complete metamorphosis: type of insect development (also known as holometabolous development) in which there is a distinct larval and pupal stage. The larval stage is different to the adult in terms of both structure and diet, and the pupa is a relatively inactive stage in which the larval tissues are broken down and rearranged into adult structures.
• Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
• Pupal stage: stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.

1. National Biodiversity Network Species Dictionary (March 2003): http://www.nhm.ac.uk/nbn/
2. Sterry, P. (1997) Collins Complete British Wildlife Photoguide. Harper Collins Publishers Ltd., London.
3. Buczacki, S. (2002) Fauna Britannica. Hamlyn, London.
4. House fly (March 2003): http://www.oznet.ksu.edu/dp_entm/extension/InsectID/Mock/HOUSEFL.html
5. O'Toole, C (2002) The new encyclopedia of insects and their allies. Oxford University Press, Oxford.
6. Common house fly and lesser house fly. ADAS (March 2003): http://www.adas.co.uk/env/environment/pestmgt/Inverts_p114&5.pdf