Incidence Of Multiple Paternity Research Articles

The evolution of pueriparity maintains multiple paternity in a polymorphic viviparous salamander

The reduction in fecundity associated with the evolution of viviparity may have far-reaching implications for the ecology, demography, and evolution of populations. The evolution of a polygamous behaviour (e.g. polyandry) may counteract some of the effects underlying a lower fecundity, such as the reduction in genetic diversity. Comparing patterns of multiple paternity between reproductive modes allows us to understand how viviparity accounts for the trade-off between offspring quality and quantity. We analysed genetic patterns of paternity and offspring genetic diversity across 42 families from two modes of viviparity in a reproductive polymorphic species, Salamandra salamandra. This species shows an ancestral (larviparity: large clutches of free aquatic larvae), and a derived reproductive mode (pueriparity: smaller clutches of larger terrestrial juveniles). Our results confirm the existence of multiple paternity in pueriparous salamanders. Furthermore, we show the evolution of pueriparity maintains, and even increases, the occurrence of multiple paternity and the number of sires compared to larviparity, though we did not find a clear effect on genetic diversity. High incidence of multiple paternity in pueriparous populations might arise as a mechanism to avoid fertilization failures and to ensure reproductive success, and thus has important implications in highly isolated populations with small broods.

Multiple Paternity in the Blue Crab (Callinectes sapidus) Assessed with Microsatellite Markers

ABSTRACT In the blue crab Callinectes sapidus (Rathbun, 1896), double ejaculations have been observed; however, it is not known if these multiple inseminations are the products of different males or if they lead to effective multiple paternities. In this study, 75 mature females and their spermathecae were genotyped for five polymorphic microsatellite loci. The incidence of multiple paternity was analyzed by comparing the genotypes of either spermathecae or individual ejaculates with the corresponding mother, and the male contribution was then deduced. Females contained double ejaculates (5.3%),which genotyping confirmed as the products of different males. In addition, a routine screening of 68 crabs from a single hatchery brood at two loci indicated more than two parents. Mitochondrial analysis confirmed that the brood shares the same mother; therefore, the extra alleles must be due to different fathers. Our findings indicate that female blue crabs are not only capable of mating with more than one male b...

High incidence of multiple paternity in an Australian snapping turtle (Elseya albagula)

Genetic parentage studies can provide detailed insights into the mating system dynamics of wild populations, including the prevalence and patterns of multiple paternity. Multiple paternity is assumed to be common among turtles, though its prevalence varies widely between species and populations. Several important groups remain to be investigated, including the family Chelidae, which dominate the freshwater turtle fauna of the Southern Hemisphere. We used seven polymorphic microsatellite markers to investigate the presence of multiple fathers within clutches from the white-throated snapping turtle (Elseya albagula), an Australian species of conservation concern. We uncovered a high incidence of multiple paternity, with 83% of clutches showing evidence of multiple fathers and up to three males contributing to single clutches. We confirm a largely promiscuous mating system for this species in the Burnett River, Queensland, although a lone incidence of single paternity indicates it is not the only strategy employed. These data provide the first example of multiple paternity in the Chelidae and extend our knowledge of the taxonomic breadth of multiple paternity in turtles of the Southern Hemisphere.

CLIMATE CHANGE, MULTIPLE PATERNITY AND OFFSPRING SURVIVAL IN LIZARDS

Recent work suggests that rising spring temperatures over recent decades have eliminated many lizard populations, and threaten many more worldwide. However, because ambient temperatures constrain activity times in ectotherms, warming conditions (as expected under global climate change scenarios) can increase the duration of seasonal opportunities for courtship and mating. Thus, in species where polyandry results in enhanced off- spring viability, a warming climate may not necessarily im- pair long-term survival. Our nine-year study of a sand lizard (Lacerta agilis) population near the northern range limit in Sweden revealed consistently higher incidence of multiple pater- nity of clutches in warmer years, and higher viability of offspring from multiply-sired clutches (presumably reflecting the advan- tages of more intense sperm competition). Any trend to warmer spring temperatures likely will benefit offspring viability in this system, by increasing a female’s opportunities to mate with addi- tional males. Many critical ecological traits are highly sensitive to ambient thermal conditions, and hence potentially will be modified by cli- mate change. A growing literature documents such effects on traits such as seasonal phenology, growth rates, and sex-determining systems (Kearney, Porter and Shine 2009; Telemeco, Elphick and Shine 2010). Ectotherms (cold-blooded animals) may be es- pecially vulnerable in such respect, because they are critically dependent upon ambient thermal heterogeneity for behavioral regulation of body temperatures and thus, local climatic condi- tions constrain the timing and intensity of fitness-relevant ac- tivities (Kearney, Porter and Shine 2009). Sinervo et al. (2010) suggest that rising spring temperatures over recent decades have eliminated many lizard populations, and threaten many more worldwide. However, the impact of this thermal shift may be very different in a cold-climate area (such as Sweden) than in a hotter area (such as Mexico, the basis for most of their analyses). In sites where operative temperatures are already close to critical thermal maxima for local reptiles, higher temperatures could be devastating. For example, animals in such an area may have little time per day when conditions are cool enough to allow activities such as mate-searching and foraging (Kearney, Porter and Shine 2009; Sinervo et al. 2010). In contrast, reptiles in cooler areas may benefit from higher temperatures, because the conse- quent ability to maintain relatively high body temperatures over longer periods may enhance organismal fitness via extended ac- tivity times and enhanced performance (Kearney, Porter and Shine 2009). Here we test the hypothesis that warmer weather increases offspring survival via elevated sperm competition (and not just as an effect of higher temperature per se).

Multiple paternity in wild‐caughtDrosophila mojavensis

Female remating frequency and sperm allocation patterns can strongly influence levels of sperm competition and reproductive success in natural populations. In the laboratory, Drosophila mojavensis males transfer very few sperm per copulation and females remate often, suggesting multiple paternity should be common in nature. Here, we examine female sperm loads, incidence of multiple paternity, and sperm utilization by genotyping progeny from 20 wild-caught females at four highly polymorphic microsatellite loci. Based on indirect paternity analyses of 814 flies, we found evidence for high levels of multiple paternity coupled with relatively low reproductive output, consistent with the high levels of female remating predicted in this sperm-limited species. Overall, we found little evidence for last -- male sperm precedence though some temporal variation in sperm utilization was observed, consistent with laboratory findings.

Microsatellites provide insight into contrasting mating patterns in arribada vs. non‐arribada olive ridley sea turtle rookeries

Molecular studies of sea turtles have shown that the frequency of multiple paternity (MP) varies between species, and between rookeries of the same species. This study uses nuclear microsatellite markers to compare the incidence of MP in two neighbouring olive ridley rookeries on the Pacific coast of Costa Rica, with contrasting nesting behaviours -- the 'arribada' population nesting at Ostional and the solitary nesters of Playa Hermosa. Using two highly polymorphic microsatellite markers, we tested 13 nests from each location and found a significant difference (P < 0.001) between the level of MP of the arribada rookery (92%- the highest found for marine turtles) and that of the solitary nesting rookery (30%). Additional analyses based on six microsatellite loci revealed no genetic differentiation between nesting females from the two locations, or between nesting females and attendant males from the Ostional breeding area. Sixty-nine per cent of the nests with MP were fathered by a minimum of three different males, and three nests showed evidence of at least four fathers. The results suggest that the differences observed in levels of MP between arribada and solitary rookeries are due to an effect of abundance of individuals on the mating system. This is supported by a regression analysis combining other paternity studies on sea turtles which shows that levels of MP increase with increasing abundance of nesting females.

Experimental assessment of ecological and phenotypic factors affecting male mating success and polyandry in northern watersnakes, Nerodia sipedon

To resolve conflicting field observations regarding the action of sexual selection, we used breeding experiments and paternity analysis of the 927 resulting offspring to assess how male size, condition, tail length, genetic similarity to the female, and variation in operational sex ratio (OSR) affected male reproductive success and the incidence of polyandry in northern watersnakes (Nerodia sipedon). Only size affected male mating success. Large males were more successful, but only when male size varied substantially and competition among males was intense (i.e., male-biased OSR). The conditional nature of the size advantage may explain why studies of free-living watersnakes have produced inconsistent results regarding the relationship between male size and mating success. Size differences between males did not affect the proportion of offspring each male sired within multiply sired litters. We found positive size-assortative mating, but only when the OSR was female biased, suggesting that smaller males had improved access to females when competition among males was reduced, but that competition with larger males still restricted mating opportunities of small males to less preferred, smaller females. Most litters (58%) were multiply sired and larger females were more likely to produce multiply sired litters, similar to free-living watersnakes. There was no association between the incidence of multiple paternity and OSR, however, suggesting that polyandry is not simply a function of opportunity, with females passively waiting for males to court them.

Genetic evidence for sexual selection in black ratsnakes, Elaphe obsoleta

We investigated benefits of polyandry and phenotypic correlates of male mating success in black ratsnakes. We used 10 microsatellite loci to identify the sires of 375 hatchlings from 34 clutches with known mothers. Multiple paternity occurred in 88% of clutches, despite the fact that ratsnakes mate when dispersed. The incidence of multiple paternity did not vary with female size or with clutch size. Hatching success tended to be higher in multiply sired clutches, but offspring from these clutches were not longer or heavier. We identified 34 males as the sires of 144 hatchlings. Most instances where sires could not be identified resulted from exclusion of all 426 potential sires that we screened. Unidentified sires were probably males that hibernated outside our study area and thus were not included in the intensive sampling at hibernacula in the study area. Among males that sired offspring, body size but not tail length contributed to success, consistent with male-biased sexual size dimorphism and male–male combat shown by this species. Large males were more successful primarily by siring more offspring per clutch rather than by siring offspring in more clutches. This may be a result of greater success in sperm competition. Neither body condition nor genetic similarity to the female was related to male mating success. Our results, in conjunction with published data on movement patterns, suggest that snakes of both genders can benefit from actively seeking multiple matings.