Sibling diversity gives sexual reproduction the advantage in a changing environment

Background: Intense competition among siblings may favour sexual reproduction because phenotypic diversity is higher among sexual siblings than asexual siblings. However, previous theoretical studies concluded that competition among sibs is ineffective at promoting sexual reproduction. Question: What are the conditions required for sib-competition to favour sexual reproduction? Search method: Mathematical and numerical analyses of the model. We identify the mechanisms that reduce the advantage of sex. Key assumptions: Sexual reproduction generates phenotypic diversity among siblings, whereas asexual reproduction doubles the reproductive rate. The virtual habitat consists of many patches, each with different environmental conditions. Only one individual the most adapted - survives in each patch. Conclusions: A greater number of environmental factors and variation of the fitness achieved by adapted phenotypes favour sexual reproduction. Intense sibling competition is likely to be an important process for maintaining sex.