The Society for the study of flies (Diptera)
Affiliated to the British Entomological and Natural History Society (BENHS)
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#1 2010-02-04 13:00:36
- Judy Webb
- Committee
- Name: Judith Webb
- Registered: 2008-02-21
- Posts: 375
Fly on Orchid
Now here is a real challenge. I'm interested in what pollinates orchids and a friend passed me this lovely picture of a Marsh Helleborine orchid from last summer with a fly in the process of probing the flower.
Despite the poor resolution of the fly, can any one suggest the family and perhaps a genus?
Judy
Last edited by Judy Webb (2010-02-04 13:01:40)
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#2 2010-02-04 13:28:59
- Howard Bentley
- Committee
- Name: Howard Bentley
- Registered: 2008-07-07
- Posts: 234
Re: Fly on Orchid
Antennae and proboscis suggest an Empid to me - can't go any further I'm afraid.
Howard
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#3 2010-02-04 14:10:09
Re: Fly on Orchid
Empis or Rhamphomyia. Impossible to say which one without specimen.
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#4 2010-02-07 11:42:38
- haematocephalus
- DF Members
- Name: Martin Harvey
- From: Buckinghamshire
- Registered: 2008-02-27
- Posts: 140
- Website
Re: Fly on Orchid
In the course of looking for potential pollinators for Military Orchid and Red Helleborine I've encountered the following empids:
- numerous Empis praevia entering Military Orchid flowers and probing deep into them with its proboscis
- several Empis (Kritempis) livida entering Military Orchid flowers
- Empis tessellata landing on Military Orchid flower (once, from photo shown to me)
- a number of small empids were seen landing on flowers of Red Helleborine and probing the surfaces of the petals with their proboscis. At least one seen to enter into mouth of flower. See attached photo. The single specimen collected was Rhamphomyia longipes.
No orchid pollinia were seen attached to any of these empids, and they don't appear to be the correct size or shape to effect pollination. Military Orchid apparently does not produce nectar, but Empis praevia appeared to be gaining some substance of importance to them (they were seen in numbers very actively probing the flowers). Some other orchids are known to produce a stigmatic secretion containing glucose and amino acids, and perhaps something along those lines is happening with Military Orchid.
Martin
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#5 2010-02-08 00:47:35
Re: Fly on Orchid
Judy's image is consistent with Rhamphomyia longipes but other species cannot be excluded. I doubt that it would be Empis praevia.
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#6 2010-02-08 13:35:26
- Judy Webb
- Committee
- Name: Judith Webb
- Registered: 2008-02-21
- Posts: 375
Re: Fly on Orchid
Thank-you everybody for the suggestions and very interesting discussion on what these flies are getting from orchid flowers, Martin. I had no idea flies might be going for anything other than nectar in their probings. When the marsh helleborines are out this summer, I will make sure to try and gain some further fly observations.
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#7 2010-02-09 02:24:01
- falky
- Registered user
- Name: Steven Falk
- From: Kenilworth
- Registered: 2009-11-30
- Posts: 320
Re: Fly on Orchid
That tiny fly is taking a risk, if it gets a pollenium stuck to its head its gonna' have one heck of a challenge! In Warwickshire we recently found a good Violet Helleborine colony, but social wasps like Dolichovespula sylvestris seem to be he main pollinators. In the New Forest mires, bees like Hylaeus pectoralis often have Dactylorhiza polleniums stuck to their heads. Us entomologist need to collate our observations, because botanists often have a very relaxed approach to citing pollinators e.g. "bees" or "flies" when infact there might be a much more interesting or specific pattern of relationships.
Falky
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