Delgado-Trejo Carlos, Reyes-López Miguel Ángel, Pérez-Ishiwara David Guillermo, Lemus-Fernández Ricardo, Camacho-Sánchez Fátima Yedith, Bedolla-Ochoa Cutzi
Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa 88710, Tamaulipas, Mexico.
Instituto de Investigaciones Sobre los Recursos Naturales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58330, Michoacán, Mexico.
Animals (Basel). 2024 Dec 24;15(1):2. doi: 10.3390/ani15010002.
Body size is one of the most important traits in the life history of vertebrates. In this work, we analyzed the morphometric traits of breeding males of the eastern Pacific green sea turtle population known as the black sea turtle on the coast of Michoacan, Mexico. The morphometric analysis indicates that males have the smallest body size compared to other males in other Chelonia populations. The size of male black sea turtles is even smaller (by 15.2 cm in average CCL) in carapace curve length (70.5 cm CCL) than females (85.7 CCL) of the same population. This suggests that males reach maturity at an earlier age than females and would have implications for mating success. The assessment of the operational sex ratio was conducted over a multi-year period (2004, 2009, 2017, and 2023). From a total of 336 h of observation, we identified 653 mating groups containing 1986 males and 669 females. The estimated operational sex ratio (OSR) during the study period was 2.96 males for every female. Among the mating groups, 34.3% consisted of only one male, while 65.7% included two or more males, with the number of males per female ranging from 2 to 17. The analysis revealed that there are interannual and monthly variations in OSR values, with observations showing a range from 2.3:1 (male to female) in 2023 to 4.3:1 (male to female) in 2009. The OSR variations show an evolving trend that can inform future strategies. In September, the ratio was 2.8:1, which changed to 3:1 in October and November, and then reached 3.3:1 in December (male/female). This gradual increase provides a clear opportunity to delve deeper into these dynamics and take proactive measures to address them positively.
体型是脊椎动物生活史中最重要的特征之一。在这项研究中，我们分析了墨西哥米却肯州海岸被称为黑海龟的东太平洋绿海龟种群繁殖期雄性个体的形态特征。形态分析表明，与其他龟鳖类种群的雄性相比，该种群的雄性体型最小。黑海龟雄性的背甲曲线长度（平均背甲曲线长度为70.5厘米）甚至比同一种群的雌性（平均背甲曲线长度为85.7厘米）还要小（平均背甲曲线长度相差15.2厘米）。这表明雄性比雌性更早达到性成熟，这可能会对交配成功率产生影响。我们在多年时间里（2004年、2009年、2017年和2023年）对有效性别比进行了评估。在总共336小时的观察中，我们识别出653个交配群体，其中包含1986只雄性和669只雌性。研究期间估计的有效性别比为每只雌性对应2.96只雄性。在交配群体中，34.3%的群体仅由一只雄性组成，而65.7%的群体包含两只或更多雄性，每只雌性对应的雄性数量从2只到17只不等。分析发现，有效性别比数值存在年际和月度变化，观察结果显示其范围从2023年的2.3:1（雄性与雌性之比）到2009年的4.3:1（雄性与雌性之比）。有效性别比的变化呈现出一种演变趋势，可为未来策略提供参考。9月时，该比例为2.8:1，10月和11月变为3:1，12月则达到3.3:1（雄性/雌性）。这种逐渐增加的趋势为深入研究这些动态并积极采取主动措施应对它们提供了明确的契机。
