You can find flies in every habitat other than the open sea. There are flies on the tops of our highest mountains and on the seashore, and in every habitat in between.
Wetlands and woodlands tend to have the most species. Coastal cliffs, sand dunes, fens, springs and ancient trees are among the habitats that have high numbers of rare species.
The feeding habits of fly larvae (commonly called maggots) are hugely varied, ranging from eating dead wood and fungi, mining inside leaves or stems, predators in soil or moss, scavengers in the nests of ants, bees or wasps, predators on the larvae of beetles under bark and even parasites within the bodies of caterpillars and snails. The list seems almost endless!
A Dipterist’s Handbook will tell you a lot more about this. (Published by The Amateur Entomologists’ Society in 2010 (2nd edition).)
Just as with other wildlife groups, many species of fly are rare, or threatened, with falling numbers. Many flies are restricted to very specific and sometimes rare habitats like ancient trees with rot holes, seepages on coastal cliffs or lime-rich springs. Eristalis cryptarum, the bog hoverfly, for example, is now known only from a few bogs on Dartmoor. Others are at threat from intensive agriculture or forestry, or by climate change. Stratiomys chamaeleon, the Clubbed General Soldierfly (photo by Judy Webb) is now very rare because of loss of the lime-rich fens it needs – these are becoming drier due to nearby water abstraction for agriculture and development.
So, flies needs conservation action just like many butterflies or bumblebees. Their sites need protecting and often require active management to retain important features like good places for larvae to grow, or flowers for adults to feed on.
In the mid-2000s, 36 species of fly were identified in the UK’s Biodiversity Action Plan (BAP) as requiring special conservation action to prevent them going extinct. These species are now recognised as species of principle importance for the conservation of biodiversity within each of the four UK countries where they occur. For more information on the relevant legislation and full lists of such species, see the government's Joint Nature Conservation Committee.
What can you do? First, it’s vital that we know as much about the distribution and status of our flies as possible, so please help to record them, ensuring that your records reach accessible national databases such as the NBN Atlas. See Recording [link to page on this website] for information on how to record flies. Secondly, help land owners and managers, protect and look after sites where rare or threatened species are known to occur. And thirdly consider becoming one of a growing numbers of guardians of rare or threatened species – if you would like to know about this, please contact the Conservation Officer.