Evolution: Love thy Neighbour

Five neighbouring populations of a cichlid fish from Lake Malawi differ in male courtship colour. Females show strong mate preferences for male coloration from their own populations. This suggests that sexual selection is an important factor contributing to speci-ation in cichlids. When Darwin [1] proposed his theory of sexual selection he was concerned mainly with explaining the wide-spread occurrence of exaggerated sexual ornaments and courtship displays, as these traits could not easily be explained by natural selection. He also noted that taxonomic groups with more pronounced sexual orna-ments tended to have more species. This suggests that sexual selection may elevate the rate at which popula-tions diversify and give rise to new species. A new stud