Divergent sexual selection via male competition: ecology is key

Citations Over TimeTop 10% of 2013 papers

Abstract

Sexual selection and ecological differences are important drivers of speciation. Much research has focused on female choice, yet the role of male competition in ecological speciation has been understudied. Here, we test how mating habitats impact sexual selection and speciation through male competition. Using limnetic and benthic species of threespine stickleback fish, we find that different mating habitats select differently on male traits through male competition. In mixed habitat with both vegetated and open areas, selection favours two trait combinations of male body size and nuptial colour: large with little colour and small with lots of colour. This matches what we see in reproductively isolated stickleback species, suggesting male competition could promote trait divergence and reproductive isolation. In contrast, when only open habitat exists, selection favours one trait combination, large with lots of colour, which would hinder trait divergence and reproductive isolation. Other behavioural mechanisms in male competition that might promote divergence, such as avoiding aggression with heterospecifics, are insufficient to maintain separate species. This work highlights the importance of mating habitats in male competition for both sexual selection and speciation.

Related Papers

• → The accumulation of reproductive isolation in early stages of divergence supports a role for sexual selection(2015)38 cited
• → Ecological versus Sexual Selection Models of Sympatric Speciation: A Synthesis(2002)77 cited
• → A TEST OF HYBRID GROWTH DISADVANTAGE IN WILD, FREE-RANGING SPECIES PAIRS OF THREESPINE STICKLEBACK (GASTEROSTEUS ACULEATUS) AND ITS IMPLICATIONS FOR ECOLOGICAL SPECIATION(2011)17 cited
• → Testing for parallel allochronic isolation in lake–stream stickleback(2015)10 cited
• → The role of sexual isolation during rapid ecological divergence: Evidence for a new dimension of isolation in Rhagoletis pomonella(2023)5 cited