Alfaro-Núñez Alonzo, Jensen Michael P, Abreu-Grobois F Alberto
Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen , Copenhagen , Denmark.
Marine Mammal and Turtle Division, National Oceanic and Atmospheric Administration , La Jolla, CA , United States.
PeerJ. 2015 Apr 7;3:e880. doi: 10.7717/peerj.880. eCollection 2015.
Despite the long debate of whether or not multiple mating benefits the offspring, studies still show contradictory results. Multiple mating takes time and energy. Thus, if females fertilize their eggs with a single mating, why to mate more than once? We investigated and inferred paternal identity and number of sires in 12 clutches (240 hatchlings) of green turtles (Chelonia mydas) nests at Tortuguero, Costa Rica. Paternal alleles were inferred through comparison of maternal and hatchling genotypes, and indicated multiple paternity in at least 11 of the clutches (92%). The inferred average number of fathers was three (ranging from 1 to 5). Moreover, regression analyses were used to investigate for correlation of inferred clutch paternity with morphological traits of hatchlings fitness (emergence success, length, weight and crawling speed), the size of the mother, and an environmental variable (incubation temperature). We suggest and propose two different comparative approaches for evaluating morphological traits and clutch paternity, in order to infer greater offspring survival. First, clutches coded by the exact number of fathers and second by the exact paternal contribution (fathers who gives greater proportion of the offspring per nest). We found significant differences (P < 0.05) in clutches coded by the exact number of fathers for all morphological traits. A general tendency of higher values in offspring sired by two to three fathers was observed for the length and weight traits. However, emergence success and crawling speed showed different trends which unable us to reach any further conclusion. The second approach analysing the paternal contribution showed no significant difference (P > 0.05) for any of the traits. We conclude that multiple paternity does not provide any extra benefit in the morphological fitness traits or the survival of the offspring, when analysed following the proposed comparative statistical methods.
尽管关于多次交配是否对后代有益存在长期争论，但研究结果仍相互矛盾。多次交配需要时间和精力。因此，如果雌性通过单次交配就能使卵受精，那为何还要多次交配呢？我们调查并推断了在哥斯达黎加托尔图格罗的绿海龟（蠵龟）巢穴中12窝（240只幼龟）的父本身份和父本数量。通过比较母本和幼龟的基因型推断父本等位基因，结果表明至少11窝（92%）存在多个父本。推断出的平均父本数量为三个（范围从1到5个）。此外，我们使用回归分析来研究推断出的窝内父本情况与幼龟适应性的形态特征（出壳成功率、体长、体重和爬行速度）、母体大小以及一个环境变量（孵化温度）之间的相关性。为了推断更高的后代存活率，我们提出并建议了两种不同的比较方法来评估形态特征和窝内父本情况。第一种是按确切的父本数量对窝进行编码，第二种是按确切的父本贡献（每窝中贡献后代比例更大的父本）进行编码。我们发现，按确切父本数量编码的窝在所有形态特征上均存在显著差异（P < 0.05）。对于体长和体重特征，观察到由两到三个父本所生的后代普遍有更高的值的趋势。然而，出壳成功率和爬行速度呈现出不同趋势，这使我们无法得出进一步结论。分析父本贡献的第二种方法在任何特征上均未显示出显著差异（P > 0.05）。我们得出结论，按照所提出的比较统计方法进行分析时，多个父本在形态适应性特征或后代存活方面并未带来任何额外益处。
