DOI: 10.5061/dryad.w3r2280ph
title: Consequences of population structure for sex allocation and sexual conflict

description: 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.
description: In a fully crossed design, using experimental evolution, we
 placed replicate populations of <i>T. urticae</i> in 4
 selection regimes with either local or global competition, and random
 <i>versus</i> budding dispersal (see details in Rodrigues et
 al. 2020 JEB) This design enabled us to follow evolution of both sex ratio
 and sexual conflict under different population structures. Each regime was
 replicated three times (GB-1, GB-2, GB-3, GR-1, GR-2, GR-3, LB-1, LB-2,
 LB-3, LR-1, LR-2 and LR-3). For each replicate population, each generation
 comprised a total of 96 mated adult females, being assigned in pairs to 48
 bean leaf patches.
 <strong>Four experiments were performed (see
 details in Rodrigues et al. 2020 JEB):</strong>
 <b><i>1. Sex allocation during experimental evolution</i></b> The sex allocation of females was measured directly in the replicate populations of each selection regime at generations 12, 17, 20 and 31. <b><i>2. Sex allocation in a common environment</i></b> In this assay, all regimes were each exposed to a common environment for 1 generation to equilibrate maternal effects before measuring the offspring sex-ratios of females that mated randomly with males from their selection regime. <b><i>3. Sex allocation in response to patch fecundity</i></b> We measured the fecundity and sex allocation of single females from our selection regimes in response to the presence of eggs laid by sterile females on the same patch. Because the eggs of the sterilised females do not hatch, we can distinguish the offspring of the focal female (adult individuals) from that of the sterilised one (unhatched eggs) within a single patch. <b><i>4. Sexual conflict</i></b> The impact of mating with males evolved under the ‘Global Budding’ and ‘Global Random’ selection regimes on the fecundity of females from the ancestral population was compared. <b>Statistical analysis</b> All analyses were carried out using the R statistical package (v. 3.0.3) and JMP13. We used Generalised Linear Mixed Models with a beta-binomial error structure and logit link function, and quasi-poisson or negative binomial error structures and log link function, to analyse the effect of selection regime on sex ratio and mean offspring production, respectively. Maximal models were simplified by sequentially eliminating non-significant terms (p &lt; 0.05) from the highest- to the simplest-order interaction, with the highest p-value to establish a minimal model. The significance of the explanatory variables in the minimal models was established using chi-squared tests. <i>A posteriori</i> contrasts with Bonferroni corrections were done to interpret the effect of selection regime when significant. Details can be found in Rodrigues et al. 2020 JEB.
description: <b>Tab
 “AcrossGenerations”</b> It includes
 all individual replicates measured each generation (generations 12, 17,
 20, 31).<sup> </sup> Selection
 Regime: ‘Global Budding’ (GB), ‘Global Random’ (GR) and ‘Local Random’
 (LR) Replicate:
 experimental replicate Generation:
 the generations at which the variable of interest was measured across
 selection regimes during experimental evolution  Day: the day
 when different replicates of the experiment were tested Sons: number
 of sons Daughters:
 number of daughters Fecundity:
 total number of offspring <b>Tab
 “CommonEnvironment”</b> It includes
 all individual replicates measured after one generation in a common
 environment (generation 31 + 1), in patches with one or two females and
 excludes experimental replicate LR-1 due to a lack of individual
 replicates.<sup> </sup> Selection
 Regime: ‘Global Budding’ (GB), ‘Global Random’ (GR) and ‘Local Random’
 (LR) Replicate:
 experimental replicate Day: the day
 when different replicates of the experiment were tested Nfemales: the
 number of females present in a patch (1 or 2) where measurements were
 taken; Sons: number
 of sons Daughters:
 number of daughters Fecundity:
 total number of offspring  
 <b>Tab
 “PatchFecundity”</b> It includes
 females that were alive on day 4 and produced offspring and excludes
 experimental replicates GR-1 and LR-1 due to a lack of individual
 replicates; Selection
 Regime: ‘Global Budding’ (GB), ‘Global Random’ (GR) and ‘Local Random’
 (LR) Replicate:
 experimental replicate Day: the day
 when different replicates of the experiment were tested Nfemales:
 number of females present in the patch Survival: The
 day one of the females died (and both were removed from the
 patch) Eggs: total
 number of eggs laid in the patch by both the sterile and fertile
 females Sons: number
 of sons Daughters:
 number of daughters Fertile:
 number of adult offspring Sterile:
 number of eggs unhatched  
 <b>Tab
 “SexualConflict”</b> It includes
 all individual replicates measured. Selection
 Regime: ‘Global Budding’ (GB), ‘Global Random’ (GR) and ‘Local Random’
 (LR) Nmates: the
 number of times a female was exposed to a male for 5 hours (single mate or
 double mates) Replicate:
 experimental replicate Box: the
 container in which several individual replicates were
 maintained Survival6:
 females were classified as alive or dead (A or D, respectively) on day
 6 Sons: number
 of sons Daughters:
 number of daughters Fecundity:
 total number of offspring