Sex allocation theory for facultatively sexual organisms inhabiting seasonal environments: the importance of bet-hedging

Adaptive explanations for dormancy often invoke bet-hedging, where reduced mean fitness can be adaptive if it associates with reduced fitness variance. Sex allocation theory typically ignores variance effects and focuses on mean fitness. For many cyclical parthenogens, these themes become linked, as only sexually produced eggs undergo dormancy needed to survive harsh conditions. We ask how sex allocation and the timing of sex evolve when this constraint exists in the form of a trade-off between asexual reproduction and sexual production of dormant eggs — the former being crucial for within-season success, the latter for survival across seasons. We show that male production can be temporally separated from or co-occur with sex, depending on whether direct (time) or indirect (population density) cues of the season's end are available, and whether population growth is density-dependent. Sex generally occurs late in the season, but is induced earlier in unpredictable environments. When only...

针对休眠的适应性解释通常会引入赌徒策略（bet-hedging）：若降低平均适合度能伴随适合度方差的减少，则该降低具备适应性优势。性分配理论通常忽略方差效应，仅聚焦于平均适合度。对于多数周期性孤雌生殖生物而言，这两类研究视角会产生关联——因为只有有性生殖产生的卵才能进入休眠状态以度过恶劣环境。我们旨在探究：当存在“无性繁殖与休眠卵有性生产之间的权衡”这一约束条件时，性分配策略与有性生殖的时机将如何演化——前者对于当季种群的存续至关重要，后者则保障种群跨季节存活。研究表明，雄性产生的时机可与有性生殖分离，亦可与其同步发生，这取决于种群能否获取季末的直接（时间）或间接（种群密度）预警信号，以及种群增长是否具有密度依赖性。有性生殖通常发生在季末，但在环境不可预测的情境下会被提前触发。当仅存在……