Datensatz

Zusammenfassung

Questions: How are the prevalence of sexual reproduction and the phenomenon of geographic parthenogenesis related to resource availability? What is the pattern in space of resource and consumer dynamics? Mathematical methods: A population dynamics model with structured resources in short supply, including a spatial gradient of consumer mortality and resource diversity. Species are modelled using quantitative genetics, combined with random mating for sexuals and clonal reproduction for asexuals. Key assumptions: Resources are limited and re-grow slowly. Only a few consumer genotypes can co-exist locally. The twofold cost of sex is incurred once per season. Conclusions: The advantage of sexual reproduction is due to the ability of the sexual population to generate offspring that can use resources that have not been exploited for some time. Resource use of the sexual population, therefore, changes continuously. This advantage is most significant at the centre of a species’ range.