Morphometric discrimination of the sibling species Drosophila melanogaster (Meigen) and D. simulans (Sturtevant) (Diptera: Drosophilidae)

The sibling species Drosophila melanogaster and D.simulans often co‐occur. Males are easily distinguished using their genitalia while females of the two species are often deemed indistinguishable. A series of nine linear and two angular measurements were taken using the heads of both males and females of both species from the same locality. A simple comparison of cheek width and eye height accurately assigned all females to species. Multivariate techniques using linear head measures alone produced very good discrimination between both species and sexes. Drosophila simulans have significantly larger eyes and narrower eye margins than D.melanogaster. Unknown females collected from this locality could be easily and reliably assigned to species.