Blow flies are so called because they were believed to “blow” their eggs, or larvae on to exposed meats. It is a general description of a number of species of large buzzing flies, which include the Bluebottle, the Greenbottle and the Flesh Fly. They all like sunlight and are attracted to meat or carrion, and all may be found around dustbins in hot summer weather.
Their feeding habits (they vomit onto food to soften it up) and filthy feet, infect food, especially meat products, as they feed or seek egg-laying sites. Their Latin names indicate their habits; Calliphora vomitoria, Sarcophaga carnaria and Cyanomyia cadaverina are but three members of the group with a great capacity for transmitting the bacterial agents of food poisoning.”
The Bluebottle is a large buzzing fly with shiny, metallic blue body, 6-12mm long.
One Bluebottle can lay up to 600 eggs, which in warm weather will hatch in under 48 hours and produce maggots which can become fully developed in a week. These maggots burrow into meat or carrion as they feed on it, and then pupate, often in loose soil, for about ten days before emerging as adult flies from the brown pupal case.
Bluebottles, like other flies, are often found around refuse tips, rotting animal matter, dirt and dustbins. They commute from filth to food, and carry bacteria on their legs, feet and bodies.
The commonest of the so-called clothes moths, with characteristic golden-bronze wings, flecked with black, folded flat along its back. The adult is about 8mm long and prefers to run rather than fly.
The related White Shouldered House Moth has mottled wings with a white head and “shoulders” where the wings join the body. Eggs are attached to fabric on which grubs will feed. The larvae are creamy-white caterpillars with brown heads.
They grow up to 18mm long, feeding on wool, hair, fur, feathers, cork or debris from food such as dried fruit or cereals, and are common scavengers in old birds’ nests, from which they may enter buildings.
The caterpillars spin silken cocoons in which they pupate. The life cycle takes several months to complete. Only the larval stage feeds, as a general scavenger as well as a textile pest.
The common or Norway rat, also known as the sewer rat. May weigh half a kilogram and measure 23cm long, exclusive of its tail.
Colour varies from brown to black but this species is distinguished from the true Black Rat by its small size, small blunt muzzle and its tail being shorter than its body length.