Within-season shifts in multiple paternity patterns in mass-nesting olive ridley sea turtles (original) (raw)
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Journal of Experimental Marine Biology and Ecology (JEMBE), 2015
Females of all seven living species of sea turtles are known to be polyandrous and show multiple paternity. The frequency of multiple paternity varies among species, and among populations of the same species. In the olive ridley sea turtle (Lepidochelys olivacea), multiple paternity levels correlate with the abundance of individuals in the mating system, being much higher in arribada rookeries than in solitary nesting sites. We used two highly polymorphic microsatellite markers (Cm84 and Or1) to assess the level of multiple paternity in an olive ridley solitary population nesting in the Gulf of Fonseca, Honduras. We found evidence of multiple paternity in 6 out of 8 clutches (75%), with a minimum number of two fathers in four clutches, and a minimum of three in the remaining two clutches. This high level of multiple paternity in a small solitary population suggests that some of the females nesting in Honduras may be coming from proximal Nicaraguan arribada nesting beaches. Historical evidences and recent satellite telemetry data support this hypothesis. In addition, we show that multiple paternity studies can be effectively performed in the absence of maternal samples, and that pooled DNA samples can be used with results comparable to individual hatchling sampling in multiple paternity analyses.
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.
Reproductive Ecology and Hatchling Behavior of Olive Ridley Sea Turtles in Honduras
2015
Females of all seven living species of sea turtles are known to be polyandrous and show multiple paternity. The frequency of multiple paternity varies among species, and among populations of the same species. In the olive ridley sea turtle (Lepidochelys olivacea), multiple paternity levels correlate with the abundance of individuals in the mating system, being much higher in arribada (mass nesting) rookeries than in solitary nesting sites. We used two highly polymorphic microsatellite markers (Cm84 and Or1) to assess the level of multiple paternity in an olive ridley solitary population nesting in the Gulf of Fonseca, Honduras. We found evidence of multiple paternity in 6 out of 8 clutches (75 %), with a minimum number of two fathers in four clutches, and a minimum of three in the remaining two clutches. This high level of multiple paternity in a small solitary population suggests that some of the females nesting in Honduras may be coming from proximal Nicaraguan arribada nesting beaches. Historical evidences and recent satellite telemetry data support this hypothesis. In addition, we show that multiple paternity studies can be effectively performed in the absence of maternal samples, and that pooled DNA samples can be used with results comparable to individual hatchling sampling in multiple paternity analyses.
Sea turtles in general are promiscuous breeders, but previous leatherback paternity studies found only a very low level of multiple paternity or none at all. Three highly polymorphic microsatellite markers (Dc99, Cc117, and Ei8) were used to investigate the paternity of a recovering population of leatherback turtles nesting at Playa Gandoca in Costa Rica, which is part of the Atlantic Costa Rican leatherback nesting population. The aim of this study was to (i) detect multiple paternity, (ii) compare the results to previous studies in the same and different nesting populations, (iii) consider the possibility of sperm storage, (iv) explore the possibility of successful inter-nesting mating taking place, and (v) determine the effect of small population size on mating patterns. Tissue samples from females and hatchlings were collected from one to three consecutive clutches (35 clutches total) of 18 nesting females included in the assay with an average sampling effort of 21.91% of offspring per clutch. Evidence of multiple paternity was found in four out of 18 females (22.22%), which had mated with two to three different males. The results from this study indicate that multiple paternity is more common than previously observed for the Atlantic Costa Rican leatherback nesting population. The analyses of successive clutches from the multiply mated females showed that paternal contribution varies between successive clutches and “new” fathers in consecutive clutches suggest the possibility of successful inter-nesting mating.
Heredity, 2002
Multiple paternity in the olive ridley sea turtle (Lepidochelys olivacea) population nesting in Suriname was demonstrated using two microsatellite loci, viz., Ei8 and Cm84. The large number of offspring sampled per clutch (70 on average, ranging from 15 to 103) and the number of alleles found at the two loci (18 and eight alleles, respectively) enabled unambiguous assessment of the occurrence of multiple paternity. In two out of 10 clutches analysed, the offspring had been sired by at least two males, which was confirmed at both loci. In both clutches, unequal paternity occurred: 73% and 92% of the offspring had been sired by the primary male. The probability of detecting multiple paternity was 0.903, and therefore there is a small chance that multiple
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.
A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries
Advances in marine biology, 2018
Why females would mate with multiple partners and have multiple fathers for clutches or litters is a long-standing enigma. There is a broad dichotomy in hypotheses ranging from polyandry having benefits to simply being an unavoidable consequence of a high incidence of male-female encounters. If females simply give in to mating when it is too costly to avoid being harassed by males (convenience polyandry), then there should be a higher rate of mating as density increases. However, if females actively seek males because they benefit from multiple mating, then mating frequency, and consequently the incidence of multiple paternity of clutches, should be high throughout. To explore these competing explanations, here we review the incidence of multiple paternity for sea turtles nesting around the World. Across 30 rookeries, including all 7 species of sea turtle, the incidence of multiple paternity was only weakly linked to rookery size (r=0.14). However, using high resolution at-sea GPS t...
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...
Molecular Ecology, 2012
For species of conservation concern, knowledge of key life-history and demographic components, such as the number and sex ratio of breeding adults, is essential for accurate assessments of population viability. Species with temperature-dependent sex determination can produce heavily biased primary sex ratios, and there is concern that adult sex ratios may be similarly skewed or will become so as a result of climate warming. Prediction and mitigation of such impacts are difficult when life-history information is lacking. In marine turtles, owing to the difficultly in observing males at sea, the breeding interval of males is unknown. It has been suggested that male breeding periodicity may be shorter than that of females, which could help to compensate for generally female-biased sex ratios. Here we outline how the use of molecular-based paternity analysis has allowed us, for the first time, to assess the breeding interval of male marine turtles across multiple breeding seasons. In our study rookery of green turtles (Chelonia mydas), 97% of males were assigned offspring in only one breeding season within the 3-year study period, strongly suggesting that male breeding intervals are frequently longer than 1 year at this site. Our results also reveal a sex ratio of breeding adults of at least 1.3 males to each female. This study illustrates the utility of molecular-based parentage inference using reconstruction of parental genotypes as a method for monitoring the number and sex ratio of breeders in species where direct observations or capture are difficult.
In this study microsatellite analyses were used to investigate whether female Leatherback turtles (Dermochelys coriacea) of the nesting-population in the Gandoca-Manzanillo Wildlife Refuge (REGAMA), Costa Rica mate polyandrously or monogamously, by examining the paternal lineages in the nests (n=35) deposited by females (n=18) in Playa Gandoca. A total of five loci were initially used to reconstruct the genotypes of nesting females and their offspring. Loci were amplified by PCR using fluorescent dye-labeled primers analysed on a LiCor automated sequencer with SAGA2. Paternal genotypes were inferred by comparing the known offspring and known maternal genotypes. Four out of 18 families (mothers with their offspring) showed extra paternal lineages, which were assumed to have derived from multiple matings. Furthermore the genetic baseline of the nesting-population was evaluated, the genetic diversity was estimated and the present gene pool was compared to the gene pool approximately 10-15 years ago.