Diptera.info

Posted by ChrisR on 01-12-2007 18:49

I am fairly sure this fly is an asilid but I'd be glad of some advice. It flew with a very similar bumblebee (see below) so there appears to be some mimicry there.

Location: French Guyana

Posted by Cor Zonneveld on 01-12-2007 22:07

Can you also make available a lateral shot, especially from the head? I'm not an expert at all, so may be I'm totally wrong, but the antennae do not loke very Asilid like.

Quite often mimicry is invoked for every furry fly - like Laphria flava. But equally often this idea is not convincing at all - no bumble bee comes to my mind when I see this magnificent Robber fly, L. flava. But here - wow! Wonderful combination of fly and bee, and near perfect match! Wing colour is to me very convincing!

Posted by ChrisR on 02-12-2007 01:11

Here's a lateral and a frontal head-shot - sorry they aren't very clear but it does have a very large proboscis - it just likes to hide it between the front legs!

I remember the asilids had another nice aspect to their mimicry. They'd wait on low foliage on sunny paths, like any asilid around the world, but in flight they buzzed, just like a bee

Edited by ChrisR on 02-12-2007 01:18

Posted by ChrisR on 02-12-2007 01:12

While I was going through the box I found this one and thought you might be interested. It isn't the same species but it's another nice asilid - with a metallic golden-dusted thorax

Posted by Guenter on 02-12-2007 21:33

#10

Compare with Dasyllis haemorrhoa (Brazil) looking like Eulaema cf. bombiformis on the homepage of Fritz Geller-Grimm:
http://www.geller...nera12.htm

Edited by Guenter on 02-12-2007 21:35

Posted by ChrisR on 04-12-2007 14:38

#11

Thanks G?nter - those photographs on your link are very convincing. If they are not exactly the same species of bee & asilid they are almost certainly the same genus!

Posted by Eric Fisher on 16-12-2007 02:59

#14

Interesting photos Chris. Excellent Eulaema mimicry, to be sure; so good, in fact, that the fly has tricked you! The asilid is Mallophora tibialis, which is in the subfamily Asilinae; Dasyllis haemorrhoa (from Fritz Geller-Grimm's excellent site) is a Laphriinae, tribe Andrenosomatini. These two genera are the most spectacular of the Asilidae that mimic Eulaema but there are others (including cryptic spp. of Dasyllis and Eulaema that all resemble a common model). The Mallophora (Asilinae) has very different antennae and wing venation compared to the Dasyllis (Laphriinae). The second robber fly is probably a Lampria sp. (also Laphriinae). Would you be able to post a dorsal shot - to help with identification?

Posted by ChrisR on 20-12-2007 15:35

#15

Hi Eric - many many thanks for correcting my identification of the first specimen

Here is a lateral shot - the metallic colours don't show very well but they are a little transient.

Edited by ChrisR on 20-12-2007 16:13

Posted by Guenter on 21-12-2007 09:09

#17

Thanks for the explanations Eric. I just remembered that I had seen this photo on Geller-Grimm's homepage and didn't have a closer look at it, but the Antenna clearly indicate the different subfamilies!

Posted by ChrisR on 22-12-2007 12:33

#18

Thanks everyone - I have a few more French Guyanan asilids here so I might post them over the Christmas period if anyone is interested

Posted by ChrisR on 23-12-2007 21:01

#20

All done - posted as individual threads this time, to reduce confusion - and with one extra specimen from a batch of Malaysian specimens I received a few years ago. Hope you enjoy them