Flies are one of our largest pollinator groups with over 7000 species in the UK. Flies belong to the order Diptera and make up around 12% of the world’s animal and plant life. Although flies account for about one third of all insects in the UK and play a huge role in our ecosystem, they are often overlooked, forgotten and cast away as pests.

Why are flies important?

Flies are extremely important as they deliver many valuable ecosystem services such as pollination, acting as predators of many pests, a food source for other animals, nutrient recycling and even medical uses.

For example, hoverflies are one of our best fly pollinators. Most of the 270 species have been identified as important pollinators; this is about the same, if not more, than considered for the solitary bees!

However, a minority of flies are considered pest species and can aid in the transmission of diseases. This often gives a bad press to all flies but many people recognise the overall importance of the group and dedicate their free time to recording flies all over the UK and studying the relationships of flies in our environment.

The International Year of the Fly 2019

To celebrate the International Year of the Fly, South West Lakes Trust and the Dipterists Forum came together in August 2019 to host an event at Countess Wear, Exeter, Devon. This is a Special Site of Scientific Interest and is managed by South West Lakes Trust and Devon Wildlife Trust. A group of volunteers from different backgrounds and specialisms joined us to carefully capture, identify and discuss the importance of flies and what we can all do to help.

What did we find?

This site has founded many interesting species in the recent past, even ones which we thought were extinct in the UK. This event did not disappoint: we found some great species and some valuable records for Devon. Some of the flies we found are below:

• Volucella inanis, a large hornet-mimicking hoverfly, scarce in Devon. The larvae of this species lives in the nests of ground-nesting social wasps where they feed on the wasp grubs.
• Tabanus autumnalis, a large marsh horsefly, whose name gives it all away. One of our largest horseflies, which is usually found in marshy habitats.
• Pipiza lugubris, a hoverfly whose larvae feed on aphids and is therefore considered as a pest control. This is a Nationally Scarce species and this is just the second record we have for Devon. 
• Eumea linearicornis, a parasitic fly, which affect some micromoth larvae. Again, this is only the second record of this species for Devon. 

How to learn more or get involved

For more information about flies and how to get involved in recording, see the Dipterists Forum website (https://www.dipterists.org.uk/). For more information about this site or similar events at South West Lakes Trust, please email [email protected].

A big thank you to everyone who attended and also to Martin Drake, Rob Wolton, Andrew Cunningham and John Day who helped us host this great event and for sharing their wealth of knowledge.

Emma Scotney

Ecologist