Picky females play a critical role in the survival and diversity of species. Image: Ole Seehausen, Fish Ecology and Evolution, Eawag, Switzerland
Women are genetically designed to be picky — particularly with their men.
Biodiversity theories have focused on the role played by adaptations in the environment, where the species that are most equipped to cope with a habitat would survive and others would gradually go extinct. However, a study conducted by scientists from the University of British Columbia (UBC) and the International Institute for Applied Systems Analysis (IIASA) in Austria suggest a different theory.
The new study presents the first theoretical model demonstrating that selective mating alone can promote the long-term co-existence of species. Researchers were able to use their model to explain how cichlids, a fish found in Lake Victoria in Africa, can co-exist in high diversity in the same habitat.
“The focus on ecological adaptation has failed to explain much of the biodiversity we see right before our eyes,” says Leithen M’Gonigle, a postdoctoral fellow at the University of California at Berkeley, who developed this work while a PhD candidate at UBC.
Their model suggests that species can coexist in the same habitat as long as two conditions are met. First, the distribution of resources they use must be inconsistent, so that groups of females with different mate preferences can occupy different resource hotspots. Second, females must pay a cost for being choosey, either through reduced survival or fecundity.
“Resource distribution are never uniform over space, even in seemingly homogeneous habitats like grassland and lakes,” Ulf Dieckmann said, a co-author of the study and leader of the Evolution and Ecology Program at IIASA.
When females are picky, they almost always suffer a cost because they spend their energy either to find a preferred mate or to avoid an undesirable one. These costs turn out to be crucial for reinforcing species’ boundaries, since they prevent females with a particular preference from invading areas dominated by males they find unattractive.
By overcoming the long-held belief that species can co-exist only if they differ in their ecological adaptations, authors suggest that this study will create greater understanding of the importance of protecting biological diversity.
