Gresham Jennifer D, Clark Anna, Keck Chloe M T, Longmire Alexis E, Nelson Abye E, Quertermous Haylee, White Ashley B, Earley Ryan
Biology Department, Pennsylvania State University, Dunmore, PA 18512, USA.
Department of Biological Sciences, The University of Alabama System, Tuscaloosa, AL 35487, USA.
Proc Biol Sci. 2025 Aug;292(2052):20250919. doi: 10.1098/rspb.2025.0919. Epub 2025 Aug 13.
Mixed-mating strategies can maximize the benefits and limit the costs of both self-fertilization and outcrossing. In addition to ecological conditions and population dynamics, the economics of mixed mating are determined by individual self-compatibility, i.e. the proportion of self-fertilization events that result in viable offspring. In gynodioecious (hermaphrodites and females) and androdioecious (hermaphrodites and males) species, self-compatibility of hermaphrodites dictates the reproductive potential of the other sex and can exert strong selection on maintenance of the non-hermaphroditic sex. Mangrove rivulus fish populations are androdioecious, and males result from hermaphrodites changing sex. Hermaphrodites overwhelmingly reproduce through internal self-fertilization, but occasionally oviposit unfertilized eggs, which males can fertilize externally. We tested the hypotheses that self-compatibility and fecundity would vary with age and as a function of genotypic variation in propensities for sex change. We reveal that fecundity and self-compatibility vary within individuals across ontogeny and among genotypes with different propensities to change sex. Hermaphrodites from genotypes that frequently change sex were significantly less fecund and self-compatible than hermaphrodites from genotypes that rarely change sex. These differences in self-compatibility and fecundity have the potential to drive mating strategy evolution in mangrove rivulus, specifically the fitness of males and associated spatiotemporal variation in sex ratios within and among populations.
混合交配策略可以使自体受精和异交的益处最大化，并限制其成本。除了生态条件和种群动态外，混合交配的经济学还由个体的自交亲和性决定，即自体受精产生可存活后代的比例。在雌全异株（雌雄同体和雌性）和雄全异株（雌雄同体和雄性）物种中，雌雄同体的自交亲和性决定了另一性别的繁殖潜力，并可对非雌雄同体性别的维持施加强烈选择。红树鳉鱼种群是雄全异株的，雄性由雌雄同体转变而来。雌雄同体绝大多数通过体内自体受精进行繁殖，但偶尔也会产出未受精的卵，雄性可以在体外使其受精。我们检验了以下假设：自交亲和性和繁殖力会随年龄变化，并作为性别转变倾向的基因型变异的函数而变化。我们发现，繁殖力和自交亲和性在个体发育过程中个体内部以及在具有不同性别转变倾向的基因型之间存在差异。频繁转变性别的基因型的雌雄同体的繁殖力和自交亲和性明显低于很少转变性别的基因型的雌雄同体。自交亲和性和繁殖力的这些差异有可能推动红树鳉鱼交配策略的进化，特别是雄性的适合度以及种群内部和种群之间性别比例的相关时空变化。
