Female preference for conspecific males based on olfactory cues in a Lake Malawi cichlid fish

Abstract

Research on reproductive isolation in African cichlid fishes has largely focused on the role of nuptial colours, but other sensory modes may play an important role in mate choice. Here, we compare the relative importance of visual and olfactory cues in mate recognition by females of a Lake Malawi cichlid species. Female Pseudotropheus emmiltos were given a choice of spawning next to a conspecific male or a male of the closely-related sympatric Pseudotropheus fainzilberi. Significant preference for conspecific males only occurred when olfactory cues were present. This suggests that divergence of olfactory signals may have been an important influence on the explosive radiation of the East African species flock.

Figure 1

Design for experiments 2 and 3. In experiment 2, there were no perforations in the acrylic partition. In experiment 3, the central inflow was turned off and the central drain pipe cut down so that no water flowed out the drains in the two outer compartments. Thus, water flowed from the male sections to the female compartment through the holes in the partitions.

Figure 2

Proportions of eggs laid by female P. emmiltos with conspecific and P. fainzilberi males for each experiment. Total numbers of eggs laid in the experiment (n) are indicated.