Consequences of population structure for sex allocation and sexual conflict

• Published in: Journal of evolutionary biology 2021-03, Vol.34 (3), p.525-536
• Main Authors: Rodrigues, Leonor, Torralba Sáez, Mario, Alpedrinha, João, Lefèvre, Sophie, Brengues, Muriel, Magalhães, Sara, Duncan, Alison B.
• Format: Article
• Language: English
• Subjects: budding dispersal; Competition; Dispersal; Dispersion; Evolution; experimental evolution; Fecundity; Females; hard and soft selection; local mate competition; Offspring; Population structure; Populations; Sampling; scale of competition; Sex; Sex ratio; Tetranychus urticae
• ISSN: 1010-061X; 1420-9101
• DOI: 10.1111/jeb.13755

Both sex allocation and sexual conflict can be modulated by spatial structure. However, how the interplay between the type of dispersal and the scale of competition simultaneously affects these traits in sub‐divided populations is rarely considered. We investigated sex allocation and sexual conflict evolution in meta‐populations of the spider mite Tetranychus urticae evolving under budding (pairing females from the same patch) or random (pairing females from different patches) dispersal and either local (fixed sampling from each subpopulation) or global (sampling as a function of subpopulation productivity) competition. Females evolving under budding dispersal produced less female‐biased offspring sex ratios than those from the random dispersal selection regimes, contradicting theoretical predictions. In contrast, the scale of competition did not strongly affect sex allocation. Offspring sex ratio and female fecundity were unaffected by the number of mates, but female fecundity was highest when their mates evolved under budding dispersal, suggesting these males inflict less harm than those evolving under random dispersal. This work highlights that population structure can impact the evolution of sex allocation and sexual conflict. Moreover, selection on either trait may reciprocally affect the evolution of the other, for example via effects on fecundity. We used experimental evolution to investigate how the scale of competition (Local or Global) and type of dispersal (Budding or Random) impacts sex allocation and sexual conflict in the spider mite, Tetranychus urticae. After ca. 30 generations of selection, populations evolving under budding dispersal showed lower levels of sexual conflict and produced less female‐biased offspring sex ratios.