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Home , Chloromyia, Chloromyia formosa, Hoverfly, Poecilobothrus, Volucella, Volucella zonaria

Flies: playing a key role in your garden

Entomologist, museum curator and author Erica McAlister discusses the myriad roles that play in the garden ecosystem.

The hover flyVolucella zonaria is harmless, but mimics a Hornet to avoid unwelcome attention.

Two years back we built a shoffice – a major. Small and fluffy with distinctive at spreading , but the larvae of the garden office – at what I thought at the elongated mouthparts, this was former munch away on , a regular time was of great expense. However, it once described to the identification garden . The Hornet mimic hover is amazing how much can change in the team at the Natural History Museum as a zonaria, one of five species in space of a year and now I practically live fluffy flying narwal; a description that is this distinctive found in the UK, in my shoffice. It also has a large window apt. The beautiful adults are , has a wonderfully cone-shaped head and from which I can stare out at my small penetrating long-tubed that many its larvae live in the nests of social . urban garden. It is fine working inside other species can’t access, whilst their not But instead of being attacked by the during the winter, but now spring is here so sociably acceptable are below wasps, the larvae act as cleaners and so a and the garden is once more becoming ground feasting on the larva of solitary harmonious relationship has developed. very active. And what is it that is . Although this may seem unpleasant, diverting me away from my work? Why the larvae have no real impact on THE LURE OF A POND it’s the flies! True flies (Diptera) are one of numbers, and parasitism is one of the If you have a pond you may see many flies the most species-rich groups of many natural ways in which species are resting on or near it. A favourite must be in the UK but, due to their perceived kept in balance in ecosystems. the long-legged flies, . reputation of being filthy or spreaders Many of these are beautifully metallic of disease, they are mostly disliked. And and the males can mostly be seen dancing this is something that I, and many other There are over 7,000 and wing-waving, trying to attract the Dipterists, believe is wholly unfair. species of fly in the UK, attention of any passing female. The most conspicuous is the semaphore fly THE DIVERSITY OF FLIES a number that grows Poecilobothrus nobilitatus, whose males There are over 7,000 species of fly in the each year and there have white wing tips and use these as part UK, a number that grows each year, and of their courtship routine. The larvae of there are many common and important are many common, and the drone flies may also be found living species to be found in your garden. These important species to be in the dank margins of garden ponds, may include species that have a liking for with their long posterior breathing tubes waste, but also others that are predators, found in your garden enabling them to breathe fresh air whilst parasitoids and, importantly for us, they munch away on the decomposing pollinators. You probably have more flies The hover flies (Syrphidae) are some material within which they are living. in your garden than many other animals of the most important pollinators with Another beautiful and elegantly named (living above ground that is). species such as the Marmalade Hover fly to visit your garden is the Broad Some of the earliest adults to arrive in Fly balteatus and the drone Centurion formosa, a green your gardens are the bee-flies, especially flies spp being common garden soldier fly (). The adults love the Dark-edged Bee-fly Bombylius visitors. Not only are the adults excellent a good umbellifer but have been found on TOMS MIKE :

18 Bird Table | Summer 2021 Some 7,216 species of fly have so far been Dark-edged Bee-flyBombylius major recorded in the UK – that Broad Centurion is more than the number of species on the planet!

Semaphore flyPoecilobothrus nobilitatus The tachinid flyPhasia hemiptera

other flowers in a sunny patch, and whilst Many of these are gardeners’ friends FIND OUT MORE the larvae develop in cow dung, they have as they attack many of the caterpillars For more information on the also been found in grass tussocks, heaps of and bugs that are eating your cabbages flies in the UK head to the rotting grass and other compost. or destroying your trees. The Oak Dipterists Forum Processionary Moth Thaumetopoea www.dipterists.org.uk and WASTE, GLORIOUS WASTE processionea was introduced on imported join to get all the benefits of And talking of compost, when I open Oaks in 2006 and has been a destructive becoming a member. the lid to my compost bin a plume of force ever since. But one of its parasitoids, owl midges () erupts from the fly Carcelia iliaca, turned up in the the dark. Resembling small hairy moths, UK in 2014 and may be able to help these species feast on the decaying matter. control the population. To date only a Along with vinegar flies (Drosophilidae) few have been recorded and the moth and house flies (Muscidae) all these caterpillars have dangerous hairs that species feast on your waste – a recycling prevent us from getting more data, so of nutrients that benefits many other we may be waiting for a while. Another animals, including birds. tachinid to visit your gardens if you are The other common whose larvae lucky is the stunning looking Phasia have a liking for waste, amongst other hempitera, a strongly sexually dimorphic things, are the blow flies (Calliphoridae). species whose males closely resemble The larvae can be found in a variety of bugs, and indeed it is shield bugs that the decomposing habitats, including carrion females are searching for. and faeces. I have Foxes that wander Flies are amazing and deliver a wide Erica’s wonderfully through my garden and so often have range of functional roles within the accessible and engaging a cluster of these flies feeding on what garden ecosystem. Despite this they are books are available from all the Foxes have nicely left for me. Often often overlooked and certainly much- good bookshops. striking in colour, and hence their other maligned. I explain many of the ecological names of green or blue bottles, these interactions of flies and other species in visitors are also important pollinators. The Secret Life of Flies and the form and function of these wonderful beasties in PARASITES A PLENTY The Inside Out of Flies. By taking more Parasitic flies (Tachinidae) are another interest in these wonderful perhaps common family of flies likely to be we can all come to appreciate both their present in your garden, and they do as amazing diversity and the roles that they

IMAGES: (CLOCKWISE FROM TOP LEFT) MIKE TOMS, WILL GEROGE, LUKAS LARGE, SUE ROBINSON SUE LARGE, GEROGE, LUKAS WILL TOMS, LEFT) MIKE TOP FROM IMAGES: (CLOCKWISE their name states, have parasitic larvae. play in our gardens and elsewhere.

Summer 2021 | Bird Table 19