Explosive speciation rates and unusual species richness in haplochromine cichlid fishes: Effects of sexual selection

摘要: Ancient lakes are often unusually species rich, mostly as a result of radiation and species-flock formation having taken place in only one or few many taxa present. Understanding why some radiate others do not is at the heart understanding biodiversity. In this chapter I discuss possible explanations for disproportionally large numbers cichlid fish lineages East African Great Lakes: halochromine fishes Lakes Victoria Malawi. show that speciation rates group higher than any other lacustrine radiation. Against background, review hypotheses put forward to explain diversity flocks. The evolution requires three processes: speciation, ecological anatomical diversification, it wrong consider relevant different processes alternatives each other. flocks high packing several phylogenetic groups haplochromines. Therefore, maybe concluded least two evolutionary models required difference between haplochromines coexistence. Subsequently work on haplochromines, particular studies aimed testing hypothesis by sexual selection. Haplochromines have polygynous mating system, conducive selection, but cichlids particularly rich. This suggests more just strong selection haplochromine richness. Recent palaeoecological evidence undermines previously popular explained richness Lake terms under varying natural regimes satellite isolated lake basins. summarize experimental comparative studies, which provide mechanisms sympatric disruptive polymorphic coloration. Such modes may (i) colour conditions where variation visible clear water, (ii) combination with factors affect population survival, unusual flocks. I argue if disruptive, can accelerate pace adaptive because resultant genetic fragmentation allows much increased rate differential response Hence, pattern resembles produced continues cause (gross) even after niche space saturated. very closely related ecologically similar role twofold: causes also maintains reproductive isolation sympatry evolved allopatry. maintenance originated through depends persistence regime within environmental signal evolved.