Sex Allocation Theory for Facultatively Sexual Organisms Inhabiting Seasonal Environments: The Importance of Bet Hedging.

Sex Allocation Theory for Facultatively Sexual Organisms Inhabiting Seasonal Environments: The Importance of Bet Hedging. Am Nat. 2018 Aug;192(2):155-170 Authors: Gerber N, Booksmythe I, Kokko H Abstract 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 the 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 and 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 indirect cues are available, the temporal spread of sex, and with it the production of dormant stages, is even larger and, given sufficient mortality, leads to endogenous population cycles in which frequent sex coincides with high densities. In all...
Source: The American Naturalist - Category: Biology Authors: Tags: Am Nat Source Type: research