Sex-specific dispersal and evolutionary rescue in metapopulations infected by male killing endosymbionts.
BACKGROUND
Male killing endosymbionts manipulate their arthropod host reproduction by only allowing female embryos to develop into infected females and killing all male offspring. Because the resulting change in sex ratio is expected to affect the evolution of sex-specific dispersal, we investigated under which environmental conditions strong sex-biased dispersal would emerge, and how this would affect host and endosymbiont metapopulation persistence.


RESULTS
We simulated host-endosymbiont metapopulation dynamics in an individual-based model, in which dispersal rates are allowed to evolve independently for the two sexes. Prominent male-biased dispersal emerges under conditions of low environmental stochasticity and high dispersal mortality. By applying a reshuffling algorithm, we show that kin-competition is a major driver of this evolutionary pattern because of the high within-population relatedness of males compared to those of females. Moreover, the evolution of sex-specific dispersal rescues metapopulations from extinction by (i) reducing endosymbiont fixation rates and (ii) by enhancing the extinction of endosymbionts within metapopulations that are characterized by low environmental stochasticity.


CONCLUSIONS
Male killing endosymbionts induce the evolution of sex-specific dispersal, with prominent male-biased dispersal under conditions of low environmental stochasticity and high dispersal mortality. This male-biased dispersal emerges from stronger kin-competition in males compared to females and induces an evolutionary rescue mechanism.
Bonte
Dries
D
University of Würzburg, Field Station Fabrikschleichach, Rauhenebrach, Germany. dries.bonte@ugent.be
Hovestadt
Thomas
T
Poethke
Hans-Joachim
HJ
D000818:Animals; D001181:Arthropods / Q000235:genetics / Q000469:parasitology*; D005075:Biological Evolution; D003198:Computer Simulation; D005260:Female; D054884:Host-Pathogen Interactions; D008297:Male; D011157:Population Dynamics; D012744:Sex Ratio; D013559:Symbiosis