Diptera are true, or two-winged, flies. They do not have a good press. In some cases that is well-deserved: tropical mosquitoes transmit diseases that kill more humans than any other animal; blow-flies and bluebottles cause food poisoning and other diseases through transmission of bacteria in food; agromyzids and anthomyzids are important pests of food crops whilst midges, blackflies and horse flies can ruin a pleasant day in the country with their bites.
But this is only part of the story. In 2008 the 7000th species for the UK was discovered and of these 7000 species the vast majority are not harmful and many provide important benefits for humans and other wildlife. Hoverflies are important pollinators and some of their larvae are major predators of aphids. Empids and Dolichopodids are predators of other small flies; tachinids or parasitic flies kill millions of moth larvae, which would otherwise defoliate plants.
So, knowing what flies we have and where they live is important in understanding our environment. In Northants we do not know how many species there let alone where they live or whether any have any real impact on our environment. Even the most popular and widely recorded flies, the hoverflies, are poorly known in the county. Indeed in the national atlas of hoverflies published in 2000, Northants does not show as many records as surrounding counties. This is almost certainly due to lack of recording rather than missing species. The position is almost certainly worse with other fly families.
The Northamptonshire and Peterborough Diptera Group was formed recently to allow those people in the area with an interest in flies to share information and to help each other with identification and recording in the old vice-county of Northamptonshire (Vice-county 32). We welcome anyone with an interest in any group of flies to join us in field meetings and workshops. If you interested please let me know. All our records are given to the Northamptonshire Biological Records Centre and, where one exists, the national recording scheme for that group of flies.