MICROSATELLITE PATERNITY ANALYSIS ON CAPTIVE LAKE MALAWI CICHLIDS SUPPORTS REPRODUCTIVE ISOLATION BY DIRECT MATE CHOICE

Three sympatrically occurring members of a cichlid fish species comple x from Lake Malawi have previously been reported to show assortative m ating in the field. Offspring from three experimental tanks each housi ng both sexes of all three members of this complex were screened at on e to four microsatellite loci to determine paternity. Reproductive iso lation was found to persist without exception under laboratory conditi ons, providing strong evidence for behavioural barriers to mating. Dir ect mate choice is suggested as the process preventing interbreeding. The results are interpreted with reference to the rapid and explosive evolution of the cichlid group.