Posted by Paul Beuk on 08-02-2010 09:54
#45
Gordon wrote:
I would like to know if anybody knows of records of great size variety in this species. I do not have measuring facilities on my microscope but the size range (in terms of body length) is at least 100% and probably more - Paul can probably measure his when they arrive and I have asked Phil to do the same with those I sent him (handed to the N.P. Manager on Tuesday afternoon).
I checked the specimens with the key to the two known species of
Centrophlebomyia and they are
furcata.
Michelsen (1983) included the second species as
anthropophaga but that has since been demonstrated to be a nomenclatorially invalid name to be considered a nomen dubium. The name under which we now know the species is
orientalis Hendel, 1907. The latter has additional small setae next to the pair of large lateral scutellar setae (absent in
furcata), has two fronto-orbital setae (presumed to be one in
furcata but occasionally there are two with the large posterior one always placed on a black spot), and has larger eyes (genae about half as high as eyes, almost as high as eyes in
furcata).
C. orientalis also is smaller (more complicated character with the size variation observed) and is more glossy.
A character given in Michelsen's key that does not appear to apply is the one of the microtrichia on the wing membrane. The base of the wing in
C. furcata is not supposed to have patches on the membrane that are devoid of microtrichia (or with very short microtrichia only) but in
furcata specimens I have the bare patches are present.
The papers dealing with
Centrophlobomyia I have seen do not mention anything specific about variation in adult size.
Freidberg (1981) gave some illustrations, one with a couple in the intercopulatory stage. In this picture the male is about 30% bigger han the female. As this is a species that may have to do with scarce resources for larval food it is possible that (lack of sufficient) resources may influence the adult size considerably (see for example the large size variation in
Scathophaga stercoraria).
Just to get all facts together: Who did already receive specimens of
Centrophlobomyia and how many males and females did you get?