Nash Cody S, Darby Philip C, Frazier Bryan S, Hendon Jill M, Higgs Jeremy M, Hoffmayer Eric R, Daly-Engel Toby S
Department of Biology University of West Florida Pensacola FL USA.
South Carolina Department of Natural Resources Marine Resources Research Institute Charleston SC USA.
Ecol Evol. 2021 Jul 29;11(17):11799-11807. doi: 10.1002/ece3.7948. eCollection 2021 Sep.
The mechanisms underlying polyandry and female mate choice in certain taxonomic groups remain widely debated. In elasmobranchs, several species have shown varying rates of polyandry based on genetic studies of multiple paternity (MP). We investigated MP in the finetooth shark, , in order to directly test the encounter rate hypothesis (ERH), which predicts that MP is a result of the frequency of encounters between mature conspecifics during the breeding season, and should therefore increase when more time is available for copulation and sperm storage. Female finetooth sharks in the northern Gulf of Mexico (GoM) have been found to reproduce with both annual periodicity and biennial periodicity, while finetooth sharks from the northwestern Atlantic Ocean have only been found to reproduce biennially, allowing us to compare mating opportunity to frequency of MP. Our results show high rates of MP with no significant difference in frequency between females in the GoM (83.0%) and Atlantic (88.2%, = .8718) and varying but nonsignificant rates of MP between females in the GoM reproducing annually (93.0%) and biennially (76.6%, = .2760). While the ERH is not supported by this study, it remains possible that reproductive periodicity and other physiological factors play a role in determining rates of MP in elasmobranchs, with potential benefits to individuals and populations.
某些分类群体中一妻多夫制和雌性配偶选择的潜在机制仍存在广泛争议。在软骨鱼类中，基于多父权（MP）的遗传学研究，有几个物种表现出不同程度的一妻多夫制。我们对长吻锯鲨的多父权现象进行了调查，以便直接检验相遇率假说（ERH），该假说预测多父权是繁殖季节成熟同种个体之间相遇频率的结果，因此当有更多时间用于交配和储存精子时，多父权现象应该会增加。在墨西哥湾北部（GoM）的雌性长吻锯鲨被发现具有年度繁殖周期和两年繁殖周期，而来自大西洋西北部的长吻锯鲨仅被发现具有两年繁殖周期，这使我们能够将交配机会与多父权频率进行比较。我们的结果显示，多父权率很高，墨西哥湾雌性（83.0%）和大西洋雌性（88.2%，P = 0.8718）之间的频率没有显著差异，墨西哥湾每年繁殖的雌性（93.0%）和每两年繁殖的雌性（76.6%，P = 0.2760）之间的多父权率有所不同但不显著。虽然这项研究不支持相遇率假说，但繁殖周期和其他生理因素仍有可能在决定软骨鱼类的多父权率方面发挥作用，对个体和种群可能有潜在益处。
