Reproductive isolation among closely related Lake Malawi cichlids: can males recognize conspecific females by visual cues?

Little is known about mate recognition systems among the species-rich cichl id necks of the African Great Lakes. Such knowledge is critical to our unde rstanding of how evolutionary processes have brought about the current dive rsity. In the present study we focused on three anatomically similar specie s of rocky shore cichlid fish Pseudotropheus (Maylandia) spp. from Lake Mal awi. We scored male responses to heterospecific and conspecific females whi ch were enclosed in separate watertight transparent chambers. Any male beha viour we observed was therefore due to visual cues alone. Although males of some species could clearly identify conspecific females on visual cues alo ne, others could not. In cases where conspecific and heterospecific females were phenotypically similar,males could not consistently distinguish betwe en them. Further experiments are required, however, to see whether males ca n recognize these females using alternative means, such as olfactory cues. (C) 1999 The Association for the Study of Animal Behaviour.