Persistence of a highly monoandrous mating system despite an extremely male-biased operational sex ratio in the firefly squid Watasenia scintillans
Persistence of a highly monoandrous mating system despite an extremely male-biased operational sex ratio in the firefly squid Watasenia scintillans
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DOI：
10.1007/s00227-023-04204-5
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发表时间：
2023-05-01
期刊：
影响因子：
2.4
通讯作者：
Hirohashi，Noritaka
中科院分区：
文献类型：
--
作者：
Alam，Md. Nur E.;Hirohashi，Noritaka
与大多数头足类动物不同，萤火虫乌贼Watasenia scintillansis 高度单雄。我们通过考虑一妻多夫交配的罕见发生以及交配季节开始时极度偏向雄性的操作性别比（OSR）来研究这种不寻常的现象。从理论上讲，偏向男性的 OSR 会加剧对配偶的竞争，导致一妻多夫现象的增加。我们估计交配期开始和结束时的 OSR（雄性/雌性）分别为 32.7 和 9.1。接下来，我们每周估计人口中的一妻多夫率，基于我们的新发现，即一妻多夫率可以根据附着在雌性体内两个精囊之一的精囊总数来随机估计。我们发现，尽管 OSR 极其偏向雄性，但雌性鱿鱼仍维持着高度单雄的交配方式。此外，一妻多夫率在生育季节没有显着变化。这些结果表明鱿鱼交配系统不受 OSR 季节变化的影响。在这里，我们讨论该物种中一夫一妻制如何持续的进化机制。
Unlike most cephalopods, the firefly squidWatasenia scintillansis highly monoandrous. We investigated this unusual phenomenon by considering the rare occurrence of polyandrous mating and the extremely male-biased operational sex ratio (OSR) at the beginning of the mating season. Theoretically, male-biased OSR can intensify competition for mates, leading to increased polyandry. We estimated OSR (male/female) as 32.7 and 9.1 at the beginning and end of the mating period, respectively. Next, we estimated the rate of polyandry in a population on a weekly basis, based on our new finding that the rate of polyandry can be estimated stochastically from the total number of spermatangia attached to one of the two seminal receptacles within a female. We found that the female squid sustains their highly monoandrous mating regime despite the fact that the OSR is extremely male-biased. Furthermore, there were no significant changes in the polyandry rate during the reproductive season. These results suggest that the squid mating system was not influenced by seasonal changes in OSR. Here, we discuss the evolutionary mechanism of how monoandry persists in this species.