Details

Autor(en) / Beteiligte

• Ashby, Ben

Titel

When does parasitism maintain sex in the absence of Red Queen Dynamics?

Ist Teil von

• Journal of evolutionary biology, 2020-12, Vol.33 (12), p.1795-1805

Ort / Verlag

Switzerland: Blackwell Publishing Ltd

Erscheinungsjahr

2020

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Parasites can select for sexual reproduction in host populations, preventing replacement by faster‐growing asexual genotypes. This is usually attributed to so‐called 'Red Queen dynamics' (RQD), where antagonistic coevolution causes fluctuating selection in allele frequencies, which provides sex with an advantage over asex. However, parasitism may also maintain sex in the absence of RQD when sexual populations are more genetically diverse—and hence more resistant, on average—than clonal populations, allowing sex and asex to coexist at a stable equilibrium. Although the maintenance of sex due to RQD has been studied extensively, the conditions that allow sex and asex to stably coexist have yet to be explored in detail. In particular, we lack an understanding of how host demography and parasite epidemiology affect the maintenance of sex in the absence of RQD. Here, I use an eco‐evolutionary model to show that both population density and the type and strength of virulence are important for maintaining sex, which can be understood in terms of their effects on disease prevalence and severity. In addition, I show that even in the absence of heterozygote advantage, asexual heterozygosity affects coexistence with sex due to variation in niche overlap. These results reveal which host and parasite characteristics are most important for the maintenance of sex in the absence of RQD, and provide empirically testable predictions for how demography and epidemiology mediate competition between sex and asex. Parasites are thought to select for host sexual reproduction due to so‐called 'Red Queen dynamics' (RQD), where host and parasite allele frequencies fluctuate through time. But differences in disease prevalence can allow sex and asex to coexist without RQD. Here, I explore theoretically how the interplay between host demography and parasite epidemiology affects selection for sex in the absence of RQD.