Abstract

Multiple paternity is widespread across animal and plant taxa and can increase genetic diversity and enhance fitness, especially in unpredictable environments. A prior study of the intertidal zone porcelain crab, Petrolisthes cinctipes (Randall, 1840), found that most females carried polyandrous broods. We tested the hypothesis that multiple paternity in P. cinctipes enhances fitness through increased average brood tolerance to temperature stress. Embryonic survival of split broods (N = 27) was measured under ambient conditions and following a single one-hour heat shock at 30 °C. Two microsatellite loci were used to genotype embryos and mothers in order to distinguish multiple from single paternity in each brood. Mean overall hatching percentage did not differ between singly and multiply sired broods; however, when exposed to a heat-shock, single-sired broods experienced 11% lower hatching success. Though relative fitness was higher in single-sired broods under non-stressful conditions, extrapolation of our results to conditions where temperatures are at least 30 °C (present-day extremes for the California coast) for > 2 days of the embryonic brood period, multiply sired broods have a relative fitness that is approximately 24 times higher after 15 generations. Maternal quality (size) and the timing of the heat shock relative to developmental timing also influence the brood response to heat shock. Our results suggest that multiple paternity reduces embryo survival variance between ambient and heat-shock conditions and that polyandrous behavior could be an advantage for P. cinctipes in the thermally variable high-intertidal zone. We conclude that multiple paternity is an important strategy for increasing fitness by genetic diversification in organisms that experience severe and unpredictable levels of environmental stress.

中文翻译：

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潮间带瓷蟹的多重亲子关系Petrolisthes cinctipes Randall，1840年（十足目：野村村：波氏菌科）是一种生活史策略，可以提高热应激时的体能

摘要

多重亲子关系在动植物分类中很普遍，并且可以增加遗传多样性并增强适应性，尤其是在不可预测的环境中。潮间带瓷蟹的先前研究Petrolisthes cinctipes（Randall，1840年）发现，大多数雌性都携带一生多卵。我们检验了假单胞菌的多重亲子关系通过增加平均育雏对温度胁迫的耐受性来增强适应性的假设。裂胚的胚胎存活（N（= 27）是在环境条件下并在30°C进行一小时的热冲击后测量的。使用两个微卫星基因座对胚胎和母亲进行基因分型，以区分每个亲代中的多个亲本和单个亲本。平均总孵化率在单亲繁殖和多繁殖繁殖之间没有差异。但是，单身育雏者在遭受热冲击时，孵化成功率降低了11％。尽管在无压力条件下单尾母鸡的相对适应性较高，但我们的结果可以推断为在育雏期超过2天的温度至少为30°C（目前为加利福尼亚海岸的极端情况）的条件下， 15个世代后，多重繁殖的亲戚的相对适应度大约高24倍。母体质量（体型）和热休克相对于发育时间的时间也会影响育雏对热休克的反应。我们的结果表明，多重亲权降低了环境和热休克条件之间的胚胎存活差异，一夫多妻制的行为可能是一种优势P. Cinctipes位于热变高潮间带。我们得出的结论是，多重亲权是在经历严重且不可预测的环境压力的生物体中通过遗传多样性提高适应性的重要策略。