Species distinction in abdominal pigmentation patterns between females of Drosophila melanogaster and D. simulans, from a Spanish population

The sibling species Drosophila melanogaster and D. simulans coexist in natural conditions. Whereas males are easily recognizable by their genital arches, females were considered to be indistinguishable but for their eye sizes. In many papers separate female counts were omitted because of this difficult characteristic. However, the abdominal pigmentation pattern was found to be different between the two species in a Spanish population. The discrimination of the females based on pigmentation differences was checked by electrophoresis and found to be very reliable.