Stalk-eyed flies

These ideas can now be backed up by experimental work. I will illustrate this by my own work using the stalk-eyed fly Cyrtodiopsis dalmanni. Males of this species have greatly exaggerated eyespan and females prefer to mate with males with wider eyespan (Wilkinson Reillo 1994). Fortunately the flies are easy to rear in large numbers under controlled laboratory conditions. We tested whether the size of the... 

These experiments show that the sexual trait (male eyespan) in stalk-eyed flies is a unique character. Both sexual and non-sexual traits decreased in size under... 

FIG. 2 Decreases in male and female eyespan in stalk-eyed flies subject to increasing larval density (David et al 1998). Male eyespan (sexual trait) is more sensitive to larval density than female eyespan (non-sexual trait). 

My research is supported by a Royal Society University Research Fellowship and Research Grants from the Natural Environment Research Council. I am greatly indebted to my coworkers on the stalk-eyed fly experiments, Tracey Bjorksten, Patrice David, Kevin Fowler and Andy Hingle, and to collaborations with Yoh Iwasa and Anders Paper Mpller. 

David P, Hingle A, Greig D, Rutherford A, Pomiankowski A, Fowler K 1998 Male sexual ornament size but not asymmetry reflects condition in stalk-eyed flies. Proc R Soc Lond B Biol Sci 265 2211-2216... 

David P, Bjorksten T, Fowler K, Pomiankowski A 2000 Condition-dependent signalling of genetic variation in stalk-eyed flies. Nature 406 186-188... 

Price T, Schluter D 1991 On the low heritability of life history traits. Evolution 45 853-861 Rowe L, Houle D 1996 The lek paradox and the capture of genetic variance by condition dependent traits. Proc R Soc Lond B Biol Sci 263 1415—1421 Taylor PD, Williams GC 1982 The lek paradox is not resolved. Theor Pop Biol 22 392—409 Wilkinson GS, Reillo 1994 Female choice response to artificial selection on an exaggerated male trait in a stalk-eyed fly. Proc R Soc Lond B Biol Sci 255 1—6... 

The presence of gangliosides in crab eye stalks (Ishizuka et al. 1970, SvENNERHOLM 1970) appears uncertain (Wiegandt 1971), while the isolation of a haemagglutinin from a lobster yielded a sialic acid component (Acton et al. 1973). Analyses of several insects including Musca domestica, Calliphora erythrocephala (Wiegandt 1971), Drosophila melanogaster larval and adult forms and the eyes and ganglia of several other flies (unpublished) showed no sialic acids. 

The occurrence of gangliosides in the eye stalk of crab, Carcinus maenas (Wiegandt, 1968), could not yet be confirmed. No gangliosides could be found in the blow fly, Calliphora erythrocephala or the house fly, Musca domestica (Wiegandt, 1970). 

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