Does polyandry really pay off? The effects of multiple mating and number of fathers on morphological traits and survival in clutches of nesting green turtles at Tortuguero (original) (raw)
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Despite the long debate of whether or not multiple mating benefits the offspring, studies still show contradicting 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). This in returns suggests that most females successfully got fecundated by at least three males. 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); and size of the mother; and an environmental varia...
Environmental, social, morphological, and behavioral constraints on opportunistic multiple paternity
Behavioral Ecology and Sociobiology, 2014
Multiple mating and multiple paternity in polytocous species have been mostly studied from an adaptive (i.e., costbenefit) perspective. Disease, time, energy, and the risk of injuries are well-known costs of multiple mating, yet from both male and female perspectives, a number of genetic and non-genetic benefits have also been identified. The effects of environmental conditions and individual-specific behavior, however, are much less well understood. Using a long-term study on yellow-bellied marmots (Marmota flaviventris), we evaluated the impacts of environmental variation, social structure, female body mass, and female docility (a personality trait) on the occurrence of multiple paternity. Multiple paternity was influenced by environmental constraints, social constraints, a female's personality, and her body mass at emergence from hibernation. Personality and mass effects were detected only when environmental or social conditions were favorable. Our results suggest that multiple paternity is mainly limited by the opportunity to have access to multiple mates and is influenced by costs or mate choice because heavier females were more likely to have litters with multiple sires than smaller ones. Future studies in other species might benefit from considering environmental constraints when studying multiple paternity.
High frequency of multiple paternity in the largest rookery of Mediterranean loggerhead sea turtles
2007
Mating systems are a central component in the evolution of animal life histories and in conservation genetics. The patterns of male reproductive skew and of paternal shares in batches of offspring, for example, affect genetic effective population size. A prominent characteristic of mating systems of sea turtles seem to be a considerable intra-and interspecific variability in the degree of polyandry. Because of the difficulty of observing the mating behaviour of sea turtles directly in the open sea, genetic paternity analysis is particularly useful for gaining insights into this aspect of their reproductive behaviour. We investigated patterns of multiple paternity in clutches of loggerhead sea turtles in the largest Mediterranean rookery using four highly variable microsatellite loci. Furthermore, we tested for a relationship between the number of fathers detected in clutches and body size of females. More than one father was detected in the clutches of 14 out of 15 females, with two clutches revealing the contribution of at least five males. In more than half the cases, the contributions of different fathers to a clutch did not depart from equality. The number of detected fathers significantly increased with increasing female body size. This relationship indicates that males may prefer to mate with large, and therefore productive, females. Our results suggest that polyandry is likely to increase effective population size compared to a population in which females would mate with only one male; male reproductive contributions being equal.
Multiple paternity in egg clutches of hawksbill turtles (Eretmochelys imbricata)
Conservation Genetics, 2011
We present the first data collected on the genetic mating system of the hawksbill turtle Eretmochelys imbricata, the only marine turtle not studied to date. We examined paternity within 12 egg clutches from ten female hawksbill turtles from Sabah Turtle Islands, Malaysia. A total of 375 hatchlings were analysed using five microsatellite markers. Results demonstrated that clutches from two out of ten females were sired by multiple males (maximum of two). Although at a low frequency, observation of multiple paternity indicates that hawksbill turtles exhibit the same genetic mating system (polyandry) as observed for other species of marine turtles. Consistent paternity across multiple clutches laid by individual females in one breeding season supports the hypothesis that sperm are stored from mating prior to nesting and are then used to fertilize all subsequent clutches of eggs that season.
Herpetologica, 2015
In oviparous species, preovulatory maternal effects such as investment in yolk quantity and composition or levels of yolk steroid hormones might potentially affect hatchling body sizes, growth rates, performance, and sex in species with temperature-dependent sex determination. We investigated the effects of egg mass and levels of testosterone and 17b-estradiol in the yolk on the phenotypes of hatchling Magdalena River Turtles (Podocnemis lewyana) in three populations in the Magdalena River drainage of northern Colombia. We hypothesized that, under homogeneous incubation conditions, the differences documented among clutches would be attributable to familial effects, caused by either heritable genetic factors or preovulatory maternal effects. Eggs were incubated artificially at the pivotal temperature for the species (33.4uC) and hatchlings were reared in the laboratory for 2 mo. Two eggs from each clutch were tested for testosterone and 17b-estradiol levels. Sex ratios, hatchling size, mass, and righting times varied both between clutches within a site and between populations. Egg mass was positively related to hatchling body size and mass, both at hatching and at 2 mo of age. Levels of 17b-estradiol concentrations influenced hatching success rates and incubation periods. Sex ratios were marginally related to 17b-estradiol levels, with clutches and sites with higher levels tending to produce fewer males. Our results provide evidence that preovulatory maternal effects play a role in influencing phenotypic attributes related to hatchling survivorship such as size, growth rate, and performance, and also seem to interact with incubation temperature to determine the sex of each individual and the sex ratio of the clutch, which has implications for both parental and offspring fitness.
Molecular ecology, 2017
Extra-pair paternity (EPP), where offspring are sired by a male other than the social male, varies enormously both within and among species. Trying to explain this variation has proved difficult because the majority of the interspecific variation is phylogenetically based. Ideally, variation in EPP should be investigated in closely related species, but clades with sufficient variation are rare. We present a comprehensive multifactorial test to explain variation in EPP among individuals in 20 populations of nine species over 89 years from a single bird family (Maluridae). Females had higher EPP in the presence of more helpers, more neighbours or if paired incestuously. Furthermore, higher EPP occurred in years with many incestuous pairs, populations with many helpers and species with high male density or in which males provide less care. Altogether, these variables accounted for 48% of the total and 89% of the interspecific and interpopulation variation in EPP. These findings indicat...
Multiple paternity and sperm storage in turtles
Herpetological Journal, 1993
Multiple paternity is the occurrence within a single clutch of offspring fathered by more than one male. This pattern may be an an adaptive feature of the mating system of turtles. Mating systems are the adaptive features of reproduction which contribute lo variation in the probability of a particular egg being fertilized by a particular sperm. Turtle populations have rarely been studied specifically in terms of multiple paternity or mating systems. Five features related to multiple paternity are discussed: spacing behaviour prior to courtship, mate-seeking and mate choice, agonistic encounters between individuals, sperm storage, and sperm competition. Several studies have examined movements and spacing behaviours in turtles, and have drawn inferences about mate seeking. At present, multiple paternity has been detected in clutches of loggerhead turtles (Caretta carella), wood turtles (Clemmys insculpta), and snapping turtles (Chelydra serpentina). In wood turtles, a relationship be...
Multiple paternity and number of offspring in mammals
Proceedings of the Royal Society B: Biological Sciences, 2018
Many cooperative social attributes are being linked to characteristics of mating systems, particularly to the rate of multiple paternity that typifies a population. Under the logic that greater offspring production by females should engender greater competition among males to mate with females, it is predicted that multiple paternity should increase with litter sizes. We tested the predicted positive association of multiple paternity and litter size with a meta-analysis of 59 species of mammals. The probability of multiple paternity and mean litter size were positively correlated, but not significantly ( Zr = 0.202). Also, the mean number of sires of litters increased with mean litter size, but not significantly ( Zr = 0.235). We developed a combinatorial formula for the influence of number of male mates and litter size on the probability of multiple paternity. We used Bayesian Markov chain Monte Carlo simulations to generate an expectation for the form of the relationship between t...
Canadian Journal of Zoology, 2011
Although mate number is perceived to be the primary factor affecting male reproductive success in polygynous systems, differences in female reproductive qualities may also influence variation in male reproductive success. We combined 32 years of data on variation in reproductive qualities (clutch size and clutch frequency) of female Midland Painted Turtles (Chrysemys picta marginata Agassiz, 1857) with genetic data on patterns of repeated paternity (i.e., stored sperm use) and multiple paternity to examine the potential influence on male reproductive success. Over 24 years , the number of reproductive females each year averaged 84 (minimum-maximum = 62-106) and, on average, 23% (minimum-maximum = 6%-40%) produced two clutches (intraseasonally). Among females with reproductive histories spanning 5-24 years (N = 167), 26% of individuals produced only one clutch annually, whereas 74% produced two clutches within a season. Among just intraseasonally iteroparous females, second-clutch production varied from 7% to 50%. Repeated paternity was observed in 97.5% of 40 paired clutches and 44% of 9 among-year comparisons of clutches from consecutive years. The frequent use of stored sperm to fertilize sequential clutches within and potentially among years can substantially increase a male's reproductive success, particularly if males can base mating decisions on phenotypic characteristics correlated with female quality.
Extra-pair paternity in birds: explaining variation between species and populations
Trends in Ecology & Evolution, 1998
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