Multiple Paternity

Rockfishes of the species-rich genus Sebastes Cuvier are marine teleosts showing a range of morphological adaptations that allow them to exploit diverse ecological niches. In the California Current region they represent a large fraction of the ichthyofaunal assemblage and constitute an important link in the trophic web. A major obstacle in studying rockfish ecology has been the identification of their larvae and juveniles. The early developmental stages of many closely related species, such as those of the subgenus Sebastomus Gill, cannot be distinguished morphologically. In this paper we present a method to identify larval rockfishes with molecular markers. The method relies on multiplex haplotype-specific PCR to yield group- or species-specific amplification products, allowing identification of larval and juvenile stages of the members of the subgenus Sebastomus. The method could be applied to any species-complex for which diagnostic mutations are known.

An explanation for female multiple mating when males offer no material benefits but sperm remains elusive, largely because of a lack of empirical support for the genetic benefits hypothesis. We used 21 microsatellite markers to test for multiple paternities among 88 litters of roe deer, Capreolus capreolus, and to investigate the inbreeding avoidance hypothesis as a potential mechanism for the evolution of female multiple mating. From paternity analyses, we found that 13.5% of polytocous litters were sired by more than one male. We also found that a half-sib relationship was more likely than a full-sib relationship for 20.5% of all litters. This is the first report of multiple paternities in a territorial ungulate species. In support of the inbreeding avoidance hypothesis, we found that parents who were strongly related produced offspring with lower individual heterozygosity that survived less well during their first summer than fawns with unrelated parents. In addition, fawns from multiple paternity litters survived their first summer better than fawns from single paternity litters. However, it remains unclear whether all female multiple paternity events in this species are provoked by an initial consanguineous mating. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society 2009, 97, 128–139.

A ubiquitous feature of animal mating systems is that males compete for females in order to reproduce. One of Darwin's (1871) great insights was that traits leading to variation among males in their ability to secure mates, either because of their attractiveness to females or their efficacy in dispatching rivals males, could evolve by sexual selection.

Evolutionary explanations for life history diversity are based on the idea of costs of reproduction, particularly on the concept of a trade-off between age-specific reproduction and parental survival, and between expenditure on current and future offspring. Such trade-offs are often difficult to detect in population studies of wild mammals.

Recent decades have seen the fast growth of cephalopod fisheries but their management is compromised by the critical gaps in our knowledge of cephalopod life histories. Molecular markers are invaluable tools for studying the evolutionary significance and management implications of variation in mating systems. We have developed seven polymorphic microsatellite loci for mating system analysis in the southern calamari Sepioteuthis australis Quoy & Gaimard 1833 using magnetic enrichment and colony hybridization techniques. Observed heterozygosities range from 32% to 100% and will have sufficient power to examine the relative success of alternate mating strategies in S. australis.

Marine turtles serve as fl agships for diverse human activities, of which
conservation programmes are especially notable. Often these conservation efforts transcend the immediate goals of marine turtle protection and biological conservation, with important achievements in the social arena. Citizen participation in conservation and other activities, leading to social inclusion and empowerment are most remarkable. At the same time, these reptiles have been important as cultural symbols, rallying devices, or marketing logos in ways that are unrelated or even contrary to biological conservation; indeed, some people even view the conservationists’ fl agships as symbols of problems and threats. Although the term has been in use since the mid-1980s to refer to the mobilising power of charismatic species, and there have been several attempts by conservation biologists to defi ne and clarify the concept, ‘fl agship species’ continues to be misunderstood and misused. Confusion between conservation and tourism fl agships is especially common. The varying uses of marine turtle fl agships leads to contradictory perceptions and expectations by different social groups, which need to be investigated. Despite their frequent lack of scientifi c design, projects employing marine turtle fl agships merit academic attention: they are valuable case studies of folk management and provide a wealth of empirical information. Analyses of the motives, cultural values, and knowledge systems associated with the use of turtle fl agships are required. Such studies must look not only at the people who are targets of fl agships, but also at the practitioners, particularly ecologists and conservationists, who use and confuse the concept. Interdisciplinary approaches are essential, and it is necessary to recognise that fl agships, like nature itself, are socially constructed, in varying ways by different social groups. Flagships provide a singular opportunity, and powerful tool, to draw disciplines and social groups together for collaboration, and for fostering research, biological conservation, and social development.

ABSTRACT: Rockfish species of the genus Sebastes are notable for being numerous and diverse. Rockfishes are unusual among fish because they fertilize their eggs internally and release live, swimming larvae. They undergo complex courting behaviors, which may allow females to be selective about their mates. The major histocompatibility complex (MHC) is implicated as having an important influence on mate selection in other fishes, especially in sticklebacks and salmonids. Research suggests that females choose mates that optimize the MHC genotypes of their offspring. Previous research on rockfishes indicates that multiple functional MHC sequences may be found in each species, and that multiple mating is common in the genus, possibly as a bet-hedging strategy against uncertain or incomplete mate-selection information. In this project, we characterized the MHC genotypes of copper (S. caurinus) and quillback (S. maliger) rockfish parents, assessed parentage of 14 larval broods, and assessed the MHC genotypes of the parents to determine if MHC-mediated mate choice was occurring. As in previous studies, we found that rockfishes possess multiple, highly variable MHC genes, and that females may mate with multiple males. We also found evidence of female preference for particular males. However, we found no strong evidence of selection based on MHC genotype. Females were not consistently selective based on relatedness, allele count, proportion of shared alleles, or minimum, mean, or maximum DNA or amino acid genetic distance. Instead, it appears that females were selective based on other measures of mate quality not considered in this study, with some hedging of bets through multiple mating also occurring.

ABSTRACT.– This study examines between-population variation of the Mekong Mud Snake, Enhydris subtaeniata (Bourret, 1934) in Thailand, Cambodia, Laos, and Viet Nam, and relates the observed patterns to previously published patterns based on molecular data. Enhydris subtaeniata were collected from six representative locations throughout its range that encompassed three important river drainage basins: the Chao Phraya, the Middle Mekong and the Lower Mekong. Data on size, sexual size dimorphism, scalation, reproductive biology and diet were used to explore biogeographical patterns revealed by a previously published phylogenetic and population genetic analysis. In several cases the size and reproductive characteristics mirrored the genetic differences and habitat differences associated with the sampled locations.

Hypotheses to explain chaotic genetic structure (i.e., a surprising degree of non-geographic temporal or spatial population differentiation) include: 1) variation in source of larval recruits, 2) self-recruitment and local subdivision, 3) variance in reproductive success (sweepstakes reproduction), and 4) pre- or post-settlement natural selection. We evaluated the relative contribution of each of these four processes to the observed patterns of genetic differentiation among geographic populations of the porcelain crab, Petrolisthes cinctipes. We genotyped about 50 individuals of each size class (new recruits, sub-adults, adults) at each of nine sites across northern California in each of three consecutive years (N= 3602). We found significant and consistent population structure (θ ~ 0.08) among sites from each replicate year of sampling (1997-1999). Significant population structure also occurred both among years and among sites, but the pattern of population structuring differed by size class. Among years, the differentiation of new recruits was highest (θ = 0.12) year-to-year, followed by the sub-adults (θ = 0.09) and finally adults (θ = 0.08). In contrast, the among-sites component was greatest among the adults (θ = 0.05), followed by the sub-adults (θ = 0.03), and least among new recruits (θ < 0.01, not significant). An overall hierarchical analysis of molecular variance (AMOVA) revealed significant genetic divergence among years (θ = 0.05), and size classes (θ = 0.08), but not among sites (θ < 0.01). Recruits at each site were genetically most similar to a different population of adults each year, and although some recruits were apparently self-recruits, no consistent patterns of assignment or genetic similarity to natal populations emerged across years, indicating that the source of recruitment is unpredictable. Temporal differentiation was stronger than spatial differentiation, and in the full hierarchical analysis, the among-years and among-size class components of variance explain the majority of observed population structure. Most studies of population genetic structuring are snap-shots based on single collections that lack explicit temporal components, and may provide an incomplete picture of population structure as a result. Overall, these data suggest that all four hypothesized mechanisms collectively create fine-scale population genetic structure in P. cinctipes, and perhaps many other marine species with similar life histories and distributions.

Approximately 50% of marked peahens (Pavo cristatus) mate more than once with lek males. Some females mate with more than one male, others copulate repeatedly with the same male. The frequency of courtship also shows marked variation. Some females repeatedly engage males in courtship interactions after they have succesfully copulated with them. The likelihood of mating with more than one male increases if a female first mates with a non-preferred (unsuccessful male). There is a non-significant tendency for females to copulate with a more successful male when remating. Peahens may mate with a non-preferred male first if they do not encounter a successful male during their initial period of choice, perhaps because the most successful male on a lek was courting another female and/or was defended by another female. There are more aggressive interactions between females in front of preferred males. Preferred males receive more repetitive courtship behaviour and repeated matings. Dominant females are more likely to engage in repetitive courtship and matings. The number of times a female initiates courtship on any one day increases with the number of other females actively courting males at a lek site on that day. We suggest that there is competition amongst females for access to preferred males and that dominant females try to monopolise these males by repeatedly engaging them in courtship interactions. We discuss the implications of these observations for the idea that female may gain directly from mate choice in a species where males contribute nothing but gametes to their offspring.

The spotted-tailed quoll (Dasyurus maculatus) is an endangered marsupial carnivore endemic to eastern Australia. A paucity of information on the dynamics of wild populations has hindered conservation of the species. The population dynamics of spotted-tailed quolls were investigated in an area of unusually high abundance in north-eastern New South Wales, where density is conservatively estimated at 0.3 km-2. Sixty individual quolls were captured on 331 occasions over 22 months. Apparent survival, timing and rate of reproduction, and morphometric data were compared with those of quolls from other areas. Population models were employed to investigate patterns in the behaviour and apparent survival of quolls in the study area. The high abundance of D. maculatus identifies the study area as vital to the conservation of quolls on mainland Australia, and to the future study of the species.

Female promiscuity is common among mammals but its advantages, particularly for marsupials, remain unclear. Using microsatellite DNA from pouch young of known mothers, we identified the most likely fathers of 25 wild spotted-tailed quolls (Dasyurus maculatus) from six litters. We aimed to determine whether young within the same litter had different fathers, and whether breeding success of males was associated with large body mass (consistent with inter-male competition) or scrotal width (consistent with sperm competition). We also explored the possible influence of promiscuity on relatedness within litters. Finally, we used data on paternity and relatedness to make inferences regarding movement and dispersal.

Four litters were sired by more than one male, and three males sired offspring in more than one litter. Known fathers had higher body mass, but not scrotal width, than males of unknown paternity status, suggesting that males may compete for access to females. Sires were less related to dams than expected by chance, and litters with multiple paternity had lower relatedness than litters sired by a single male.

Radio-tracking of spotted-tailed quolls Dasyurus maculatus (Marsupialia: Dasyuridae) in the forested ranges of north-eastern New South Wales revealed that home ranges were extensive, with males occupying large, overlapping ranges [minimum convex polygon (MCP) up to 757 ha] and females occupying smaller, non-overlapping territories (MCP up to 175 ha). Quolls were partly arboreal, although most activity occurred on the ground or on fallen logs. Hollow logs were most frequently used as dens, but rock crevices, burrows, tree hollows and artificial structures were also used. Individual quolls were located in up to nine different dens and, with the exception of maternal dens, rarely sheltered in the same location on successive days. The large home ranges of the spotted-tailed quoll and the non-overlapping nature of female ranges necessitate very large areas of habitat to support viable populations. Fallen timber, used extensively for shelter and in travelling, may serve to enhance the quality of habitat for the species, and should be retained by forest and wildlife managers.

Proposed benefits of multiple paternity include increased reproductive output, elevated fitness of progeny, and maintenance of population genetic diversity. However, an alternative consideration is whether multiple paternity is simply an unavoidable byproduct of sexual conflict, with males seeking to maximize mating encounters while females seek to minimize the stress of copulation. Here we examine the polyandrous mating system in sharks, with a focus on the reproductive genetics of the shortspine spurdog, Squalus mitsukurii. Members of the genus Squalus are long-lived, slow-growing, and employ the longest gestation period of any vertebrate. To evaluate multiple paternity and genetic diversity in S. mitsukurii, we genotyped 27 litters plus 96 individuals with eight microsatellite loci. Further, 670 bp of the mtDNA control region were sequenced in 112 individuals to examine population structure. Squalus mitsukurii in Hawaii show low genetic diversity relative to other sharks (π = 0.0010 ± 0.0008) and no significant population structure in the Hawaiian Archipelago. Direct allele counts and Bayesian approximations returned concordant estimates of 11% multiple paternity, the lowest observed in sharks to date. Pearson correlation analysis of multiple paternity and heterozygosity in five shark studies reveals an R2 = 0.40. Though non-significant, these data indicate that multiple paternity may promote retention of genetic diversity. Considering the protracted reproductive interval of S. mituskurii, sexual conflict that results from conflicting male and female reproductive strategies may favor the development of female mating avoidance behavior to minimize trauma. In S. mitsukurii this behavior includes segregation of sexes and an asynchronous reproductive cycle.

"The Central Plain is one of the major natural regions of Thailand. It is a wide alluvial plain with little topographic relief consisting of multiple river basins. The many natural and anthropogenic
wetland habitats in the region make it an ideal habitat for many aquatic and semi-aquatic species. We document the semi-aquatic snake communities associated with aquatic habitats in the Central Plain of Thailand. We surveyed a diversity of localities in the Central Plain and documented the occurrence of 10
species based on a sample of 786 snakes. The snake communities of the region are dominated by homalopsid snakes (7 species). Enhydris enhydris, the Rainbow Water Snake, was the dominant species at all sites surveyed and accounted for 80.2% of the snakes collected. We collected data on sexual dimorphism, sex ratios, reproduction, and diet. We found that all species examined, except Homalopsis buccata, exhibited
female-biased sexual size dimorphism and we document significant differences in length and mass among Central Plain populations of E. enhydris. Sex ratios varied among populations, from male to female dominated. A large proportion of the E. enhydris examined were in reproductive condition (67.5%, n =
160). For E. enhydris, we documented clutch size based on vitellogenic follicles (mean = 16.7 ± 1.07) and oviducal eggs (mean = 11.4 ± 2.00), a positive relationship between female body length and clutch size, and a mean relative clutch mass of 0.37 ± 0.07. Diet analysis indicated that homalopsid species are piscivorous and species of the Cyprinidae were the most common diet item. Our data suggest homalopsids eat numerous,
relatively small prey items. The Central Plain snake assemblage is similar in species composition to other semi-aquatic snake communities in Indochina. The populations of E. enhydris from the Central Plain are large in body size and exhibit high reproductive effort compared to other populations of E. enhydris for which information is available. The robustness of the Central Plain population may be related to the high productivity of the wetlands of the Central Plain. We discuss historical, biogeographical, biotic, and abiotic factors that may contribute to the differences observed among semi-aquatic snake communities in the region and the differences documented among populations of E. enhydris."

Elasmobranch mating systems have received growing attention in the past few years due to worldwide overexploitation of shark populations. Few studies to date have examined mating systems in sharks because of difficulty in sampling. The sandbar shark (Carcharhinus plumbeus) is heavily harvested around the world and is the dominant species in the main commercial fishery for large coastal sharks in the United States. In contrast, Hawaii hosts one of the few unexploited populations of sandbar sharks, and represents an opportunity to gather data on the reproductive biology of a vulnerable shark species without the confounding effects of fishing mortality. We examined the frequency of multiple paternity in Hawaiian sandbar sharks using 130 individuals (20 gravid females with 3-8 pups each per litter) surveyed with 6 polymorphic microsatellite loci, and determined that 8 of the 20 litters (40%) were multiply sired. A Bayesian approach estimated the frequency of multiple mating in this population at 43.8%, with a 95% confidence interval of 23-63%. We conclude that multiple paternity and genetic monogamy occur with roughly equal frequency in the Hawaiian sandbar shark population. This study may serve as groundwork for understanding the impact of commercial fishing pressure on elasmobranch mating systems.

We tested for presence or absence of multiple paternity in single litters from each of three congeneric shark species in Hawaii, the sandbar shark (Carcharhinus plumbeus), bignose shark (Carcharhinus altimus), and Galapagos shark (Carcharhinus galapagensis). Based on eight polymorphic microsatellite loci, we excluded paternity by a single sire in sandbar and bignose sharks, but not in the Galapagos shark. This doubles the number of shark species tested for multiple paternity, and is the first demonstration of multiple paternity in sandbar and bignose sharks. These results open the door for further work on what appears to be a common reproductive mode with potential population-level consequences.

Investigations of paternity among marine crustaceans are rare, but the few studies of brachyuran crabs that have been done to date suggest that most broods derive from single males. Here I use two hypervariable microsatellite loci to genotype a dozen brooded embryos from each of 10 gravid females of the porcelain crab, Petrolisthes cinctipes (Anomura: Porcellanidae). Based on the number of non-maternal alleles detected among the offspring, at least 1 to 3 males must have fathered each of these broods, and most females were multiply mated. Using a Bayesian approach, I estimate the frequency of multiple mating to be roughly 92.5% in the Bodega Bay population, with a 95% confidence interval of 71-100% of females producing broods of multiple paternity.

Sexual and asexual reproduction and associated population dynamics were investigated in the colonial ascidian Didemnum rodriguesi Rocha & Monniot, 1993 (Didemnidae) in southern Brazil. Investment in sexual (production of new individuals) and asexual (colony growth) reproduction was compared between seasons. Permanently marked quadrats were repeatedly photographed to measure changes in colonies. Eggs and larvae were counted monthly in collected colonies. This species alternates seasonally between sexual (summer) and asexual (winter) reproduction. In summer, colonies were smaller, brooded eggs and larvae and recruitment rates were greater, while in winter, colony size was larger and eggs and larvae were absent. There is a relationship between fecundity and colony area. Fragmentation and fusion of colonies were similar in summer and winter, as well as mortality. In conclusion, D. rodriguesi has a lifecycle usual for high latitude ascidians with a limited time length for sexual reproduction and alternate investment in sexual and asexual reproduction along the year.

Aim The role of human activities in species biogeography can be difficult to identify, but in some cases molecular techniques can be used to test hypotheses of human-mediated dispersal. A currently accepted hypothesis states that humans mediated the divergence of two species of spiny-tailed iguanas in the Ctenosaura hemilopha species complex, namely C. conspicuosa and C. nolascensis, which occupy islands in the Sea of Corte´s between the peninsula of Baja California and mainland Mexico. We test an alternative hypothesis that follows the traditional knowledge of the Seri Indians and states that the divergence of these species was not mediated by humans. Location Mexico, including Baja California, Sonoran and Sinaloan coastal regions, and Isla San Esteban and Isla San Pedro Nolasco in the Sea of Cortes.

Methods We analysed mitochondrial (cytochrome b and cytochrome c oxidase subunit III) DNA sequences from four species in the C. hemilopha species complex. Maximum parsimony and Bayesian inference were used to infer matriarchal genealogical relationships between the species and several outgroup taxa. Bayesian methods were used to estimate divergence times for the major nodes on the trees based on previously published, fossil-calibrated priors. Results Our analysis indicated that lineages within the C. hemilopha species complex diverged long before human colonization of the Americas. The divergence of C. nolascensis and C. conspicuosa could not be attributed to Seri translocations. The matriarchal genealogy of the species complex currently defies a simple biogeographical interpretation.

Main conclusions We conclude that humans did not mediate the divergence of C. nolascensis and C. conspicuosa. This conclusion is consistent with the traditional knowledge of the Seri people. These results demonstrate the utility of molecular techniques in investigating potential cases of human-mediated dispersal of plants and animals, and reinforce the importance of considering traditional knowledge in the formation of scientific hypotheses and the interpretation of results.