The Society for the study of flies (Diptera)
Affiliated to the British Entomological and Natural History Society (BENHS)
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#1 2019-01-03 12:03:50
- Weirdoslr
- Registered user
- Name: Array Array
- Registered: 2018-12-22
- Posts: 1
faecal analysis
I am working on a dietry study of swallows using faecal analysis. I can recognise Stratiomyidae(often Beris sp) by wings and scutellum, but often associated with this is a head in which the eye facets are of different sizes - larger anteriorally than posteriorally. Does anyone know if this is the Stratiomyid mentioned? I also find Simulium sp. The antennae of both these sp are very similar. Does Simulium have eye facets of different sizes?
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#2 2019-01-03 13:16:58
- Howard Bentley
- Committee
- Name: Howard Bentley
- Registered: 2008-07-07
- Posts: 795
Re: faecal analysis
The standard text on the British Stratiomyidae is "British Soldierflies and their Allies" by Alan Stubbs and Martin Drake. The following is quoted from this book's description of adult Stratiomyidae (p.293): "The males of several genera have a sharp separation between small facets in the lower quarter or third of the eye and larger facets above...In the species of Stratiomys there is either a sharp division or a more gentle gradient in facet size, according to species, and the latter condition is also typical of Beris." The males of Simulium species have larger facets at the top of the eyes and smaller facets below, while in females all the facets are of equal size. Many fly groups exhibit thi difference in facet size, usually (always?) restricted to males, where it is believed to be associated with swarming behaviour. Hope this is helpful.
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