Mar 272017
 

Bombylius major (Dark-edged Bee-fly) in a Cotswold churchyard.

No, the title of this note is not an unexpectedly pious exclamation from the script of a new Batman film, but rather the consequence of an idea that has been developing in my mind as one of the county fly recorders.

Dark-edged Bee-fly feeding.

Our most common bee-fly is Bombylius major (Dark-edged Bee-fly) which appears quite early in the year (the first Gloucestershire records in 2017 are from 15 March). The species has two essential site requirements: the presence of solitary bees (because its own larvae feed on the larvae of the bees) and of the spring wild flowers which the adult flies visit for nectar. These requirements may be met in a wide range of habitats, including urban parks and gardens, but are not so easily found across intensively farmed countryside.

Dotted Bee-fly at rest.

Although it is much less common, Bombylius discolor (Dotted Bee-fly) can also be seen in Gloucestershire. The two species are difficult to distinguish unless the pattern of dark markings on their wings can be seen clearly.

Last year it occurred to me that churchyards might be good places to search for bee-flies, particularly in the Cotswolds where some village churchyards provide oases of semi-natural vegetation within many square miles of agricultural land. This year I am continuing to explore this idea during the flight season of the adult bee-flies, which are active between March and June.

A tightly mown churchyard – but bee-flies inhabit a marginal semi-natural strip.

Sadly, even some of our most picturesque rural villages have churchyards in which the only natural vegetation permitted is tightly mown grass. The solitary bees may still make use of some of these places, but they are unlikely to attract bee-flies in the absence of unmanicured corners where native flowers can grow.

A corner of the most floral semi-natural churchyard I have found.

On the other hand there are churchyards subject to less intensive management (either deliberately or thanks to benign

neglect) where springtime flowers can flourish; my experience so far suggests that, with a little patient searching, the Dark-edged Bee-fly can almost always be found in such places.

There are also, of course, intermediate situations, such as a spacious, mown grass churchyard I have visited where several trees have been removed in the recent past, but the ground flora of violets and celandine that they once sheltered is hanging on; presumably the surrounding grass will eventually overwhelm these flowers, but for the moment they are still attracting bee-flies. Unsympathetic management is an obvious threat to the flora and fauna of our churchyards; perhaps the presence or absence of bee-flies could play a part in assessing their wildlife value,  in both rural and urban parts of the county.

Heaven for bee-flies, bumblebees and other pollinating insects – another corner of that very floral churchyard.