When adaptation promotes coexistence

Peafowl males have prominent ornaments, birds song for courtship, and flowers are beautiful and attractive for pollen transporters. Such characteristics appear to be adaptive at the level of individuals, but do not necessarily increase population growth rate. Therefore, these are, at the level of species, “wasteful”, making the species weaker to other species in competition for resources. Our collaboration group named this process as “intra-specific adaptation load,” and developed mathematical models, showing that strong intra-specific competition leads to a coexistence of a number of species that would have otherwise excluded each other (“competitive exclusion”). This new mechanism, which has been rarely considered in biodiversity research, may actually play a pivotal role in maintaining the biodiversity on earth.