Nick Upton's picture

Rare Beefly

Observed: 25th June 2012 By: Nick UptonNick Upton’s reputation in InvertebratesNick Upton’s reputation in InvertebratesNick Upton’s reputation in InvertebratesNick Upton’s reputation in Invertebrates
Villa sp. Bombyliidae
Villa sp.
Villa sp.
Villa cingulata? tibia hairs
Description:

I came across this beefly yesterday feeding on Hogweed in a Wiltshire chalk grassland site and am pretty sure it's a Villa sp. The best known UK species is Villa modesta, but that lives in coastal sand dunes. From the habitat this is more likely to be Villa venusta (Heath Villa) or Villa cingulata (Downland Villa), the only other UK Villa spp. and both are rare. I know Villa are tricky but is it possible to ID the species?

Identifications
Species interactions

No interactions present.

Comments

dshubble's picture

A nice villa in the country

Well, I agree it's Villa, but this is tricky as you say. It's not venusta which would have a broader dark stripe at the front edge of the wing, but modesta & cingulata are very similar and you really need to look at the scales & spines on the dorsal surface of the hind tibia and it's not unknown for modesta to turn up inland, though rarely - it's larger on average than cingulata but the size ranges overlap so not much help unless you have a specimen at one end of the size range. This one's a male (note the silver-white patch at the base of the wing). As the habitat suggests cingulata, worth tracking another one down!

Dave

Nick Upton's picture

Which villa??

Many thanks Dave, that helps to narrow it down. This one was very faithful to a small clump of hogweed and I may find it again if I go again soon and I'm pretty sure I saw another one at another limestone grassland site a few miles away later in the day. When you say it's worth tracking down another - do you mean I should collect one and send to a museum for ID confirmation / for recording purposes? (Who, where, in what state?) I normally only take photos, and collecting rarities seems counterintuitive, but I do have a net if the information that results justifies it. Or if I can enlarge a hind leg shot, might that be enough? The pattern of hairs and spines is visible in some. Clearest pic now attached.

Nick Upton, naturalist and photographer.

ChrisR's picture

I'd contact David Gibbs via

I'd contact David Gibbs via Diptera.info and let him have a look. That's a very interesting record :)

Nick Upton's picture

cingulata?

Hi Chris, thanks. I may not know what things are immediately, but I knew I hadn't seen a beefly like this in the UK before, only in Greece where I've photographed Villa spp., so took lots of pics. I have posted some on the diptera.info site: http://www.diptera.info/forum/viewthread.php?thread_id=48533 and mossnisse directed me to a scandinavian key which suggests cingulata to me (but I'm not used to using keys), as does the habitat/location well away from the coast, but a direct approach to David may be needed. I'll try to get on with that today.

Nick Upton, naturalist and photographer.

David Gibbs's picture

So far

all inland Villa i have seen have proved to be V. cingulata. Your one is in the right habitat and not far from the site where i first found it in Somerset. So, on the balance of probability it is V. cingulata. However, on the continent V. modesta occurs inland in many dry habitats so, personally, i think any new site should be backed by a male specimen. The only way to be sure of the identification beyond reasonable doubt is to examine the epiphallus.

Nick Upton's picture

Male Villa

Many thanks for your input and suggestions on this. I gather that my insect was a male by the obvious white mark at the base of the wing, so I should know what to look for.

Nick Upton, naturalist and photographer.