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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 (r² = 0.14). However, using high resolution at-sea GPS tracking we show that the specifics of movement patterns play a key role in driving packing density and hence the likely rate of male-female encounters. When individuals use the same focal areas, packing density could be 100 × greater than when assuming individuals move independently. Once the extent of adult movements in the breeding season was considered so that movements and abundance could be combined to produce a measure of density, then across rookeries we found a very tight relationship (r² = 0.96) between packing density and the incidence of multiple paternity. These findings suggest that multiple paternity in sea turtles may have no benefit, but is simply a consequence of the incidence of male-female encounters. [ABSTRACT FROM AUTHOR]

Multiple paternity behavior (MP) has been recorded for seven elasmobranch orders. It remains unclear how this common behavior evolved and whether it occurs in all elasmobranchs or in certain lineages. Although MP may provide genetic benefits, elasmobranchs display an aggressive courtship behavior and females may become severely wounded, making multiple mating costly. Females can perform multiple matings to avoid excessive harassment in males (polyandry by convenience hypothesis). Studies challenge this hypothesis, suggesting that females are often able to avoid mating attempts by inappropriate males and copulate with several potential. In this study, an scientiometric analysis was performed concerning elasmobranch species presenting MP records, to reconstruct the evolutionary history of the complex sexual behavior in this group. The results indicate that MP behavior is widespread in the subclass, suggesting that it may have been originated in the common ancestor of elasmobranchs (plesiomorphic state). The data indicate a knowledge gap regarding the detection of MP in other elasmobranch orders and we suggest that investigative studies on the neglected elasmobranch and chimaera orders are required. [ABSTRACT FROM AUTHOR]

Clinids of the tribe Clinini are viviparous fishes occurring in the temperate waters of southern Africa. Females of the genus Clinus exhibit reproductive traits suggesting multiple paternity. These traits include prolonged gestation periods, matrotrophy and superfetation. We tested the hypothesis that broods of the species C. cottoides are sired by multiple males with the use of microsatellites. We genotyped three broods from known mothers and analysed the relationships within each brood using the software program COLONY, we also used allele counting to find evidence of multiple paternity. Our results revealed that multiple paternity occurred in all three broods analysed; two broods likely had two sires and one brood three sires. One male appear to have fathered offspring with separate females. Our study represents the first molecular analysis of parentage in C. cottoides. [ABSTRACT FROM AUTHOR]

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 ¼ 0.202). Also, the mean number of sires of litters increased with mean litter size, but not significantly (Zr ¼ 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 the probability of multiple paternity and mean litter size. Under the assumption of random samplings of numbers of mates, the expected association of the probability of multiple paternity and mean litter sizes among species was positive, curvilinear and relatively high. However, the empirical probabilities of multiple paternities were much less than expected, suggesting that behavioural factors (such as mating-associated behaviours) or ecological characteristics (such as population density) probably limit the number of male mates for reproductive females. The probability of multiple paternity in a population is an estimate of mating patterns that does not closely reflect the number of sires of individual litters. We suggest use of the estimated probability of mating success for males as an alternative measure of their contribution to the mating system. [ABSTRACT FROM AUTHOR]

Female octopuses are known to store sperm from multiple males they encounter throughout a breeding season, before laying a single clutch with mixed paternity. Although octopuses display a broad range of precopulatory behaviours, and both sperm competition and cryptic female choice have been hypothesized to occur, the current understanding of how these processes influence resulting paternity remains limited. This study aimed to identify behavioural factors associated with paternity patterns and the capacity of females to bias paternity postcopulation to specific males in the southern blue-ringed octopus, Hapalochlaena maculosa . Genetic markers and controlled, sequential, laboratory pairings of genotyped individuals were used to examine paternity patterns and compare them to relative signatures of male sperm remaining in female oviducal glands after egg laying. Multiple paternity was discovered in all 12 laboratory-reared clutches. There was no indication that the relative time spent in copulation affected the resulting paternity. Males that waited for females to terminate the copulation had greater paternity when they were the first candidate male, but this was not the case among second candidate males. The relative quantities of candidate male alleles detected in female oviducal glands after egg laying were consistent with relative paternity of the candidate males in all but three cases. In one of these, sibship analysis revealed that the male that obtained less paternity than expected was in fact the female's full-sibling brother. Although this study found no evidence for female postcopulatory selection of male sperm, anecdotal evidence suggests that female H. maculosa might benefit from polyandry if chemical processes can favour clutch fertilization by unrelated males. Future studies, investigating paternity bias among genotyped males of varying, but known relatedness to the female, might help to validate this pattern. [ABSTRACT FROM AUTHOR]

Variation in levels of multiple paternity (MP) among species, populations and individuals has important ecological and evolutionary ramifications including maintenance of genetic diversity and offspring fitness benefits. Within species, differences in breeding experience and body size may affect the levels of MP via mate choice preferences. The present study tested these ideas in an Australian loggerhead turtle ( Caretta caretta) population at Mon Repos Beach (24°48°S, 152°27°E, Queensland) to determine if variation in MP was related female breeding history or body size, or influenced embryo and hatchling outcomes in clutches from 29 females and 552 hatchlings. MP was moderately high (65.5%), but experienced females did not have higher levels of MP than first-time breeders (neophytes), nor was female size related to the number of sires. Instead, more subtle patterns emerged: multiply sired clutches of experienced females were sired by more males than those of multiply sired neophyte clutches and primary fathers sired a greater proportion of offspring when mated to larger females. These findings are consistent with cross-seasonal sperm storage in experienced breeders contributing to a small proportion of paternity and size-dependent variation in polyandrous mating behaviour. MP did not influence offspring size, levels of within-clutch morphological variation or hatching success. However, the number of sires of a clutch was positively correlated with proportion of developed embryos, suggesting a fitness advantage of MP. From a population perspective, male-biased sex ratios likely contribute to the MP levels observed, and levels could decrease with projected feminisation of populations due to climate change. [ABSTRACT FROM AUTHOR]

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 (r² = 0.14). However, using high resolution at-sea GPS tracking we show that the specifics of movement patterns play a key role in driving packing density and hence the likely rate of male-female encounters. When individuals use the same focal areas, packing density could be 100 × greater than when assuming individuals move independently. Once the extent of adult movements in the breeding season was considered so that movements and abundance could be combined to produce a measure of density, then across rookeries we found a very tight relationship (r² = 0.96) between packing density and the incidence of multiple paternity. These findings suggest that multiple paternity in sea turtles may have no benefit, but is simply a consequence of the incidence of male-female encounters. [ABSTRACT FROM AUTHOR]

Multiple paternity is a common phenomenon among marine turtles. This behavior is associated with male density and sperm storage in marine species, but no fitness benefits have been detected in offspring from multiple-sired nests. The green turtle ( Chelonia mydas ) has been commonly studied around the world. Evidence of multiple paternity in C. mydas ranges from almost zero to 100%. In this study, we investigate multiple paternity in C. mydas using microsatellites to determine the number of males that fertilized clutches during two nesting seasons at a high-density nesting beach in the west coast in Michoacán state, Mexico. The minimum number of eggs per nest needed to detect multiple paternity and the number of males involved in fertilization were also assessed. The results indicated that multiple paternity occurred in up to 75% of the nest samples. In addition, the minimum number of eggs per nest required to detect multiple genotype contributions was 6.66 for two fathers, 12.44 for three fathers, 15.49 for four fathers and 20.24 for five fathers. Females fertilized their eggs using contributions from different males between and within clutches during the nesting season. This behavior led to a multiple paternity pattern, which can be advantageous during different life stages but not necessarily during early life. [ABSTRACT FROM AUTHOR]

The article focuses on examining the characteristics of multiple paternity in Chinese softshell turtles (Pelodiscus Sinensis). It focuses on the importance of Pelodiscus Sinensis with respect to their nutritional and medicinal value, observing the sperm storage in different clutch samples, and information on the need for captive breeding of Pelodiscus Sinensis is also presented.

Polyandry resulting in multiply-sired litters has been documented in the majority of elasmobranch species examined to date. Although commonly observed, reasons for this mating system remain relatively obscure, especially in batoids. The round stingray ( Urobatis halleri) is an abundant, well-studied elasmobranch distributed throughout the northeastern Pacific that we used to explore hypotheses regarding multiple paternity in elasmobranchs. Twenty mid- to late-term pregnant females were sampled off the coast of southern California and their litters analyzed for the occurrence of multiple paternity using five nuclear microsatellite loci. In addition, embryo sizes and their position within the female reproductive system (i.e., right or left uterus) were recorded and used to make inferences for patterns of ovulation. Multiple paternity was observed in 90% of litters and male reproductive success within litters was relatively even among sires. High variability in testes mass was observed suggesting that sperm competition is high in this species, although male reproductive success per litter appeared to be relatively even. Using embryo size as a proxy for fertilization, females were found to exhibit a variety of ovulation patterns that could function to limit a male's access to eggs and possibly promote high rates of multiple paternity. Our study highlights that elasmobranch mating systems may be more varied and complex than presumed and further investigation is warranted. [ABSTRACT FROM AUTHOR]

Sea turtles are promiscuous breeders with both males and females mating multiply. Due to this mating system, multiple paternity (MP) occurs in sea turtle clutches, and the frequency of MP varies greatly within and among species. In this study, the paternity of a population of loggerhead sea turtles ( Caretta caretta ) nesting on Dalyan Beach in Turkey was investigated using two highly polymorphic microsatellite markers (CcP2F11 and CcP7C06). Tissue samples collected from randomly selected hatchlings (a total of 522 hatchlings) from two to three successive clutches (a total of 25 clutches) of 10 nesting females were used for paternity analysis with an average sampling effort of 28.2% of offspring per clutch. Evidence of MP in seven out of 10 females (70%) was found, and it was detected that four out of these seven females mated with at least two males, whereas the remaining three females with at least three males. By analysing the successive clutches of females, it was detected that both the number and genotype of contributing sires was same in all clutches of a given female, possibly due to the lack of successful inter-nesting mating in this population. The high frequency of MP implies the possible high genetic diversity within this population. This study indicates that the density of individuals may be the reason of the high frequency of MP in this relatively small population because mating takes place mainly in a narrow area in Dalyan. The possible mating behaviours of the sea turtles and their population structures were discussed in light of the high frequency of MP within this population reported for the first time. [ABSTRACT FROM AUTHOR]

Multiple paternity was assessed in Octopus minor using microsatellite DNA markers. Octopus minor adults were captured in traps and kept in indoor cement ponds. The females spawned after several days. Ten broods (B1-B10), each containing 15 embryos and the maternal octopus, were maintained until the embryos reached the stage at which DNA could be extracted and used for genotyping. Multiple paternity was tested using five microsatellite DNA markers and the results proved the hypothesis that multiple paternity occurs in O. minor (observed in six out of the 10 broods). Analysis with GERUD software gave the minimum number of fathers and showed that four broods were sired by a single male, three were sired by two different males and three were sired by three different males. In brood B10, the number of fathers identified by the single-locus method was one fewer than that by the GERUD method. Of the six multiple paternity broods, four (66.7%) showed significant skew from equal paternal contributions, which indicated that sperm competition and/or cryptic female choice may be important for post-copulatory paternity bias in this species. [ABSTRACT FROM AUTHOR]

In this study, multiple paternity ( MP) was investigated in three commercially important shark species, common smoothhound Mustelus mustelus, dusky shark Carcharhinus obscurus and scalloped hammerhead Sphyrna lewini occurring in southern Africa. Reduced marker panels of between five and six microsatellite loci were constructed for each species and used to genotype and assess the presence of MP in a total of 60 M. mustelus individuals from six litters, 90 C. obscurus individuals from 14 litters and 54 S. lewini individuals from 13 litters. Analysis in GERUD and COLONY revealed the presence of MP in all three species. Multiple paternities were observed in 67, 35 and 46% of the litters of M. mustelus, C. obscurus and S. lewini, with corresponding average sire size of 1·6, 1·4 and 2·0, respectively. The variation in the rate of MP among the three species is in accordance with previous studies whilst the comparatively high frequency of MP observed for M. mustelus, matches what has previously been reported for shark species demonstrating aggregation behaviour. [ABSTRACT FROM AUTHOR]

Multiple mating is common among ticks, a large group of haematophagous ectoparasites, but multiple paternity has rarely been investigated. Multiple paternity may be common because the resultant increased genetic diversity allows ticks to rapidly evolve in relation to host responses and increases colonisation potential in novel habitats. Knowledge concerning mating systems is important because ticks may have profound effects on their hosts and are the principal transmitters of many pathogenic agents. In the current study, we investigated the mating system of the nidicolous tick Ixodes arboricola . These ticks attach to their bird hosts in the nest, which restricts gene flow but facilitates finding a partner off-host. Having genetically variable offspring may be beneficial for ticks which may encounter very different conditions when dispersed to the nest of another host type. We conducted an experiment in which female ticks fed on great tit nestlings and mated with two males in three treatments of the females: mating with both males before feeding, mating with one male before and the other male after feeding, or mating with both males after feeding. We investigated paternity with microsatellites. In a complementary experiment we investigated male preference for unfed or engorged females, and measured mating duration. We predicted (i) there would be multiple mating by I. arboricola males and females, leading to multiple paternity, and (ii) males would prefer to mate with engorged females and those matings would last longer because engorged females present a higher probability of successful reproduction. We found multiple paternity within clutches but no indications of sperm precedence. Males preferred to mate with engorged females and those matings lasted significantly longer, even including attachment beyond egg deposition. We suggest such mate guarding and male preference for mating after feeding is adaptive because there is no first male precedence. Male preference for mating after feeding may also be adaptive because dispersal is low and females are available after the blood meal. [ABSTRACT FROM AUTHOR]

Conservation strategies can be most effective when factors influencing the persistence of populations are wellunderstood, including aspects of reproductive biology such as mating system. Crocodylians have been traditionally associated with a polygynous mating system, with genetic studies revealingmultiple paternity of clutches in several species. The endemic Cuban crocodile, Crocodylus rhombifer, is currently listed as Critically Endangered, and is one of the least understood crocodylian species in terms of its mating behavior. Here, we tested a hypothesis of multiple paternity in the Cuban crocodile by collecting genotypic data at nine microsatellite loci for 102 hatchlings from five nests sampled at the Zapata Swamp captive breeding facility and analyzing them in relation to data previously collected for 137 putative parents. All five nests showed evidence of multiple paternity based on the numbers of alleles per locus, with sibship analyses reconstructing all nests as having four to six full-sib family groups. Accordingly, mean pairwise relatedness values per nest ranged from 0.21 to 0.39, largely intermediate between theoretical expected values for half-siblings (0.25) and full-siblings (0.50). It is not possible to differentiate whether the multiple paternity of a nest was due to multiple matings during the same breeding season, or a result of sperm storage. Our results reveal that the C. rhombifer mating system is likely best characterized as promiscuous and suggest that the standard practice of enforcing a 1:2 sex ratio at the captive breeding facility should be altered in order to better maintain a demographically and genetically healthy ex situ population. [ABSTRACT FROM AUTHOR]

Understanding how some species may be able to evolve quickly enough to deal with anthropogenic pressure is of prime interest in evolutionary biology, conservation, and management. Wild boar ( Sus scrofa scrofa) populations keep growing all over Europe despite increasing hunting pressure. In wild boar populations subject to male-selective harvesting, the initially described polygynous mating system may switch to a promiscuous/polyandrous one. Such a change in the mating system, where potentially more males sire a litter at one reproductive event, may be associated with the retention of high genetic diversity and an increase of litter size. We tested these hypotheses by estimating the number of sires per litter based on a six-year long monitoring of a wild boar population subject to particularly high harvesting pressure. Our results show a high and stable genetic diversity and high rates of multiple paternity compared to other populations, thus depicting a promiscuous/polyandrous mating system in this population. We also show that litter size is positively linked to the number of sires, suggesting that multiple paternity increases fecundity. We finally discuss that multiple paternity may be one of the factors allowing rapid evolution of this population by maintaining both genetic and phenotypic diversity. [ABSTRACT FROM AUTHOR]

Norway rats are an abundant synanthropic species in urban settings and serve as reservoirs for many pathogens. Attempts to control their populations have met with little success. Recent genetic studies suggest that local populations are structured and few individuals move significant distances, but there is substantial gene flow. To understand these observations and their implications on control strategies, we genotyped 722 rats from 20 alleys in Baltimore to establish paternity for 180 embryos. Up to 88 males may have contributed to the litters. All litters were sired by ≥2 males, with an average of 4.9 (range 2-7) males. For dams and sires with known locations, most matings (71.7%; n = 46) occurred among animals from different alleys. The average distance between sires and dams was 114 meters (range 8-352 meters). In 10/17 (58.8%) litters, the majority of the identified sires were captured in different alleys than the females. Sires were significantly less related to females than were the males captured in the females' alleys. Although rats may generally restrict their movements, either receptive females and/or breeding males engage in mate-seeking behaviors that extend beyond movement patterns at other times. This geographically extends the sizes of local populations and buffers them from the impacts of control strategies that focus on local infestations. [ABSTRACT FROM AUTHOR]

The Norway rat, Rattus norvegicus, is one of the most important pest species globally and the main reservoir of leptospires causing human leptospirosis in the urban slums of tropical regions. Rodent control is a frequent strategy in those settings to prevent the disease but rapid growth from residual populations and immigration limit the long-term effectiveness of interventions. To characterize the breeding ecology of R. norvegicus and provide needed information for the level of genetic mixing, which can help identify inter-connected eradication units, we estimated the occurrence of multiple paternity, distances between mothers and sires, and inbreeding in rats from urban slum habitat in Salvador, Brazil. We genotyped 9 pregnant females, their 66 offspring, and 371 males at 16 microsatellite loci. Multiple paternity was observed in 22% (2/9) of the study litters. Of the 12 sires that contributed to the 9 litters, we identified 5 (42%) of those sires among our genotyped males. Related males were captured in close proximity to pregnant females (the mean inter-parent trapping distance per litter was 70 m, ±58 m SD). Levels of relatedness between mother-sire pairs were higher than expected and significantly higher than relatedness between all females and non-sire males. Our findings indicate multiple paternity is common, inbreeding is apparent, and that mother-sire dyads occur in close proximity within the study area. This information is relevant to improve the spatial definition of the eradication units that may enhance the effectiveness of rodent management programs aimed at preventing human leptospirosis. High levels of inbreeding may also be a sign that eradication efforts are successful. [ABSTRACT FROM AUTHOR]

Mating system variability is known to exist between and within species, often due to environmental influences. An open question is whether, vice versa, similar environmental conditions entail congruent mating behavior, for example in terms of multiple paternity, in species or populations sharing largely comparable breeding modes. This study employed microsatellite markers to investigate the incidence of multiple paternity in Cyprichromis coloratus and Cyprichromis leptosoma, two sympatric, closely related, mouthbrooding Lake Tanganyika cichlids with similar ecological and behavioral characteristics including the formation of open-water schools. Mouthbrooding females of both species were collected from the same mixed-species breeding school at the same time, minimizing environmental variation during courtship and mating. In C. coloratus, four of 12 broods had more than one sire, with a mean of 1.33 reconstructed sires per brood. C. leptosoma exhibited multiple paternity in 18 of 22 broods, with a mean of 2.59 or 2.86 reconstructed sires per brood according to the programs gerud and colony, respectively. In addition, two broods were found to contain offspring transplanted from another brood. There was no significant difference in brood size between species, but mean sire number did differ significantly. Hence, substantial similarity in reproductive behavior along with shared environmental conditions during courtship and spawning did not lead to equal rates of polyandry or sneaking in the two species. [ABSTRACT FROM AUTHOR]

We identified multiple paternity in 52.9% of the clutches of Hermann's tortoise Testudo hermanni boettgeri using polymorphic microsatellite markers. In addition we demonstrated sperm storage across seasons. DNA was extracted from the amniotic fluid adhering to the eggshell's inner surface, a procedure suitable for easy, non-invasive DNA sampling in conservation and breeding programs. To improve the informative value of monomorphic single tandem repeat (STR) markers we additionally analyzed single nucleotide polymorphism (SNP) variability. [ABSTRACT FROM AUTHOR]

1. The patterns of multiple paternity among the progeny of females are key properties of genetic mating systems. Femalemultiple mating should evolve due to direct or indirect benefits, but it may also partly be driven by the encounter rate with different potential mates. 2. In this study this hypothesis was experimentally tested in the European earwig (Forficula auricularia L.) by establishing experimental mating groups that differed in the number of males and females (i.e. density). The number of sires and mean sibling relatedness in each clutch were estimated using microsatellite-based paternity analysis. 3. As predicted, the mean number of sires per clutch was significantly increased, and sibling relatedness decreased, in the higher density treatment where more potential male mates were available. This change was less than proportional to the number of males in the mating groups, indicating that mechanisms limiting multiple paternity in large mating groups were involved. There were no significant relationships between female reproductive success or male siring success with morphology (body size, weight, and forceps size). 4. The present results show that multiple paternity in F. auricularia clutches is partly determined by the availability of male mates and suggest that this effect is modulated by mechanisms in males and/or females that limit multiple paternity. [ABSTRACT FROM AUTHOR]

Knowledge about mating patterns is essential for understanding and explaining rates of reproduction and genetic potential of copepods populations. The aim of this study was to examine (1) the occurrence of multiple paternity in Temora longicornis, (2) the effect of multiple paternity (if present) on the females reproductive output, and (3) whether mating is random or some individuals have a higher than average chance of fertilizing or being fertilized (super individuals). We show that multiple paternity is common in this copepod species, that females benefit from multiple matings by increased offspring production, and that a relatively small fraction of the males and females in a population account for most of the offspring production. In both males and females, mating is nonrandom. Superior individuals with a higher than average matings success were identified both among females and among males. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background The puzzle of the selective benefits of multiple mating and multiple paternity in social insects has been a major focus of research in evolutionary biology. We examine paternity in a clade of social insects, the vespine wasps (the yellowjackets and hornets), which contains species with high multiple paternity as well as species with single paternity. This group is particularly useful for comparative analyses given the wide interspecific variation in paternity traits despite similar sociobiology and ecology of the species in the genera Vespula, Dolichovespula and Vespa. We describe the paternity of 5 species of yellowjackets (Vespula spp.) and we perform a phylogenetically controlled comparative analysis of relatedness, paternity frequency, paternity skew, colony size, and nest site across 22 vespine taxa. Results We found moderate multiple paternity in four small-colony Vespula rufa-group species (effective paternity 1.5 - 2.1), and higher multiple paternity in the large-colony Vespula flavopilosa (effective paternity ~3.1). Our comparative analysis shows that colony size, but not nest site, predicts average intracolony relatedness. Underlying this pattern, we found that greater colony size is associated with both higher paternity frequency and reduced paternity skew. Conclusions Our results support hypotheses focusing on the enhancement of genetic diversity in species with large colonies, and run counter to the hypothesis that multiple paternity is adaptively maintained due to sperm limitation associated with large colonies. We confirm the patterns observed in taxonomically widespread analyses by comparing closely related species of wasps with similar ecology, behavior and social organization. The vespine wasps may be a useful group for experimental investigation of the benefits of multiple paternity in the future. [ABSTRACT FROM AUTHOR]

In animals in which the two sexes invest relatively similar amounts of resources in their young, the number of mates is expected to affect male and female reproductive success similarly and gender conflicts on the number of mates may not arise. Correspondingly, in non-selfing, simultaneous hermaphrodites with long-term monogamy, the two partners are expected to alternate repeatedly their sexual roles and invest similarly in their offspring. Therefore, the gender conflict on the number of mating partners should not arise. However, when >2 conspecifics are present, hermaphrodites are known to plastically adjust their behavior and sex allocation and compete for mating repeatedly in the male role. We tested whether this leads to multiple paternities of single egg clutches in experimental replicates of small and large groups of non-selfing, egg-trading, behaviorally monogamous polychaete worms ( Ophryotrocha diadema) by using neutral genetic markers to estimate paternity. Multiply fertilized egg cocoons were common in these worms; two or more individuals succeeded in fertilizing the same egg cocoon and mate competition increased with group size. Multiply fertilized egg cocoons had a higher proportion of eggs developing into mature worms than singly fertilized egg cocoons. Possibly singly fertilized cocoons had a lower fertilization rate owing to low sperm counts and aflagellate sperm. [ABSTRACT FROM AUTHOR]

In some species, sperm is stored within the female reproductive tract for months to years, and yet remains viable to fertilize eggs and produce offspring. Female red-sided garter snakes store sperm for over 7 months of winter dormancy. In previous work, we demonstrated that these stored sperm account for an average of 25 % paternity of a litter when the female mates with a male at spring emergence. Here, we tested whether last-male sperm precedence was prevalent when a female mates with two males during the spring. On average, paternity was shared equally among the first (P proportion of paternity of the first male to mate) and second males (P) to mate in the spring, and stored sperm (P), but the variance in paternity was high. Thus, last male sperm precedence may diminish when a female has more than two mates. Male size did not affect paternity, but, as the interval between matings increased, P increased at the expense of P. Interestingly, as the second spring male's copulation duration increased, P also increased at the expense of P. This result suggests that female influence over sperm and/or copulatory plug transfer during matings may also affect which male fathers her offspring in response to coercive matings as we assisted females to mate for their second mating. Finally, all females were spring 'virgins'; consequently, sperm stored from autumn matings (and/or previous spring matings) remain competitive even when faced with two rivals in sperm competition and is likely the driver of the evolution of sperm longevity. [ABSTRACT FROM AUTHOR]

Multiple mating and multiple paternity in polytocous species have been mostly studied from an adaptive (i.e., cost-benefit) 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. [ABSTRACT FROM AUTHOR]

Despite a great number of studies on extra-pair paternity in birds, the actual roles of males and females in extra-pair contacts is poorly understood, as detailed behavioural studies comparing the reproductive performance of the two sexes prior to egg laying are relatively scarce. Here, we investigated mating behaviour (copulations and aggressive interactions), time budget and body condition (size-adjusted body mass and baseline corticosterone level) in the little auk ( Alle alle), a monogamous and highly colonial, Arctic seabird. We performed the study in a large breeding colony of the little auk in Hornsund (Spitsbergen). We found that the males frequently attempted extra-pair copulations (EPCs), although these contacts were almost always unsuccessful, mostly because of the females' rejection behaviour. These results clearly indicate that genetic monogamy is maintained through female control. Nevertheless, males tried to protect their paternity by staying in close proximity to their females and aggressively intervening when their mates became involved in EPCs. Compared to females, males also spent more time in the colony guarding nest sites. Despite the apparent sex differences in the time budget and frequency of aggressive interactions, body condition was similar in the two sexes, indicating comparable parental investments during the mating period. [ABSTRACT FROM AUTHOR]

Multiple paternity was recently observed in a population of the brown smoothhound shark, Mustelus henlei, from Las Barrancas, Baja California Sur, Mexico, with litters demonstrating the greatest percentage of multiple paternity for any shark species (93 % of litters and an average number of sires = 2.3). To determine whether this frequency is consistent elsewhere in the species' range, 4 polymorphic microsatellite loci were used to determine the frequency of multiple paternity in 18 litters of M. henlei from Santa Catalina Island, CA, sampled in 2004, 2008, and 2012. Multiple paternity varied among sampling years with 2004 demonstrating multiple sires for 40 % of sampled litters ( n = 10) with an average of 1.4 sires per litter and 2008/2012 demonstrating a total lack of multiply sired litters ( n = 8). Although multiple paternity was detected in this study, the range of frequencies observed is lower than that observed in the Mexican population. Based on these findings, investigators should take location into consideration when assessing the existence of multiple paternity in future studies of elasmobranch species. [ABSTRACT FROM AUTHOR]

Background: Inferring of parentage in natural populations is important in understanding the mating systems of a species, which have great effects on its genetic structure and evolution. Muricidae, a large group (approximately 1,600 species) of marine gastropods, are poorly investigated in patterns of multiple paternity and sperm competition based on molecular techniques. The veined Rapa whelk, Rapana venosa, a commercially important muricid species with internal fertilization, is an ideal species to study the occurrence and frequency of multiple paternity and to facilitate understanding of their reproductive strategies. Methodology/Principal Findings: We developed five highly polymorphic microsatellites in R. venosa and applied them to identify multiple paternity in 19 broods (1381 embryos) collected from Dandong, China. Multiple paternity was detected in 17 (89.5%) of 19 broods. The number of sires per brood ranged from 1 to 7 (4.3 on average). Of the 17 multiply sired broods, 16 (94.1%) were significantly skewed from equal paternal contributions, and had a dominant sire which was also dominant in each assayed capsule. Conclusions: Our results indicate that a high level of multiple paternity occurs in the wild population of R. venosa. Similar patterns of multiple paternity in the 2–6 assayed capsules from each brood imply that fertilization events within the body of a female occur mostly (but not entirely) as random draws from a “well-but-not-perfectly blended sperm pool” of her several mates. Strongly skewed distributions of fertilization success among sires also suggest that sperm competition and/or cryptic female choice might be important for post-copulatory paternity biasing in this species. [ABSTRACT FROM AUTHOR]

Background: Inferring of parentage in natural populations is important in understanding the mating systems of a species, which have great effects on its genetic structure and evolution. Muricidae, a large group (approximately 1,600 species) of marine gastropods, are poorly investigated in patterns of multiple paternity and sperm competition based on molecular techniques. The veined Rapa whelk, Rapana venosa, a commercially important muricid species with internal fertilization, is an ideal species to study the occurrence and frequency of multiple paternity and to facilitate understanding of their reproductive strategies. Methodology/Principal Findings: We developed five highly polymorphic microsatellites in R. venosa and applied them to identify multiple paternity in 19 broods (1381 embryos) collected from Dandong, China. Multiple paternity was detected in 17 (89.5%) of 19 broods. The number of sires per brood ranged from 1 to 7 (4.3 on average). Of the 17 multiply sired broods, 16 (94.1%) were significantly skewed from equal paternal contributions, and had a dominant sire which was also dominant in each assayed capsule. Conclusions: Our results indicate that a high level of multiple paternity occurs in the wild population of R. venosa. Similar patterns of multiple paternity in the 2–6 assayed capsules from each brood imply that fertilization events within the body of a female occur mostly (but not entirely) as random draws from a “well-but-not-perfectly blended sperm pool” of her several mates. Strongly skewed distributions of fertilization success among sires also suggest that sperm competition and/or cryptic female choice might be important for post-copulatory paternity biasing in this species. [ABSTRACT FROM AUTHOR]

Sperm competition ( SC) is a major component of sexual selection that enhances intra- and intersexual conflicts and may trigger rapid adaptive evolution of sexual characters. The actual role of SC on rapid evolution, however, is poorly understood. Besides, the relative contribution of distinctive features of the mating system to among species variation in the strength of SC remains unclear. Here, we assessed the strength of SC and mating system factors that may account for it in the closely related species Drosophila buzzatii and Drosophila koepferae. Our analyses reveal higher incidence of multiple paternity and SC risk in D. buzzatii wild-inseminated females. The estimated number of fathers per brood was 3.57 in D. buzzatii and 1.95 in D. koepferae. In turn, the expected proportion of females inseminated by more than one male was 0.89 in D. buzzatii and 0.58 in D. koepferae. Laboratory experiments show that this pattern may be accounted for by the faster rate of stored sperm usage observed in D. koepferae and by the greater female remating rate exhibited by D. buzzatii. We also found that the male reproductive cost of SC is also higher in D. buzzatii. After a female mated with a second male, first-mating male fertility was reduced by 71.4% in D. buzzatii and only 33.3% in D. koepferae. Therefore, we may conclude that postmating sexual selection via SC is a stronger evolutionary force in D. buzzatii than in its sibling. [ABSTRACT FROM AUTHOR]

Genetic variation within and among populations is influenced by the genetic content of the founders and the migrants following establishment. This is particularly true if populations are small, migration rate low and habitats arranged in a stepping-stone fashion. Under these circumstances the level of multiple paternity is critical since multiply mated females bring more genetic variation into founder groups than single mated females. One such example is the marine snail Littorina saxatilis that during postglacial times has invaded mainland refuge areas and thereafter small islands emerging due to isostatic uplift by occasional rafting of multiply mated females. We modelled effects of varying degrees of multiple paternity on the genetic variation of island populations colonised by the founders spreading from the mainland, by quantifying the population heterozygosity during both the transient colonisation process, and after a steady state (with migration) has been reached. During colonisation, multiple mating by males increased the heterozygosity by in comparison with single paternity, while in the steady state the increase was compared with single paternity. In the steady state the increase of heterozygosity due to multiple paternity is determined by a corresponding increase in effective population size. During colonisation, by contrast, the increase in heterozygosity is larger and it cannot be explained in terms of the effective population size alone. During the steady-state phase bursts of high genetic variation spread through the system, and far from the mainland this led to short periods of high diversity separated by long periods of low diversity. The size of these fluctuations was boosted by multiple paternity. We conclude that following glacial periods of extirpation, recolonization of isolated habitats by this species has been supported by its high level of multiple paternity. [ABSTRACT FROM AUTHOR]

Abstract: The number of sires per litter was determined for the leopard shark (Triakidae: Triakis semifasciata) to investigate the potential effect of female-biased aggregation behavior on the frequency of multiple paternity (F MP). Four highly polymorphic microsatellite markers were developed and used to genotype 449 pups from 22 litters (20.4±7.0 pups per litter) sampled from pregnant females collected from a female-dominated leopard shark aggregation in La Jolla, California, USA. Multiple paternity was detected in 8 of 22 litters (F MP =36.4%), each having two sires per litter. The relatively low F MP (compared to other shark species) is generally consistent with the hypothesis that female aggregation behavior reduces mating attempts by males and thus limits genetic polyandry. Significant interannual variability in F MP observed between two years of the study (2010: F MP =20.0%, n =10, and 2011: F MP =83.3%, n =6) appears to be correlated with the frequency of males in the aggregation. Although females may benefit indirectly from mating with multiple males by promoting sperm competition and hedging against nonviable sperm, the most probable explanation for genetic polyandry in the leopard shark appears to be “convenience polyandry,” where females acquiesce to superfluous mating attempts if the costs of resistance outweigh the costs of capitulation. Thus, F MP is expected to increase as the male-to-female ratio increases and as capacity of females to resist coercive males decreases at the time and place of mating. [Copyright &y& Elsevier]

Multiple paternity is extremely common in natural populations of almost all reptiles studied to date, suggesting that pay-offs from polyandrous mating systems are important in these taxonomic groups. However, strong evidence in support of direct or indirect benefits to females is scarce. We examined the relationship between polyandry and components of female reproductive success and offspring fitness in the promiscuous green turtle (Chelonia mydas), a species that exhibits highly variable levels of multiple paternity. We did not detect any clear fitness benefits to polyandrous females in this study, and we discuss the potential of sexual conflict to influence female mating patterns in marine turtles. We show that polyandrous females produce significantly smaller clutches than monandrous females, highlighting a potential cost to polyandry in green turtles. Furthermore, multiple paternity was more common in returning females (recorded breeding in a previous season) than in females nesting for the first time at our study site, possibly reflecting increased encounter rates with males or sperm storage across breeding seasons. Our results reveal potentially complex influences of female traits, environment, and mating strategy on components of reproductive success, and we discuss the challenges associated with unraveling the costs and benefits of multiple mating in natural populations. [ABSTRACT FROM PUBLISHER]

Sibling cannibalism is commonly observed in marine species. For instance, intrabrood cannibalism has been documented in marine gastropods with direct development, suggesting a relationship between embryo behavior and the evolution of life history strategies. However, there has been little effort to document the factors driving sibling cannibalism in marine species. The kin selection theory suggests that the level of relatedness plays an important role in cannibalism patterns. We examined Crepidula coquimbensis, a marine gastropod that broods and encloses its brooded offspring in capsules. Encapsulated embryos show sibling cannibalism and high levels of intracapsular multiple paternity. Given these features, cannibalistic behavior may be driven by kin-relatedness. To test this hypothesis, we constructed artificial aggregations of embryos to mimic three levels of relatedness: high, medium and low. For each category of aggregation, the cannibalism rate and benefits (i.e. size at hatching of surviving offspring) were estimated. In addition, at the end of embryo development, we performed parentage analyses to determine if cannibalism was associated with the relatedness between cannibal and victim embryos. Our results show that the intensity of sibling cannibalism increased in aggregations characterized by the lowest level of relatedness. There were important benefits of cannibalism in terms of hatching cannibal size. In addition, cannibalism between embryos was not random: the variation in reproductive success between males increased over the course of the experiment and the effective number of fathers decreased. Altogether, these results suggest that polyandry may play an important role in the evolution of sibling cannibalism in C. coquimbensis and that kin selection may operate during early embryonic stages in this species. [ABSTRACT FROM AUTHOR]

Sibling cannibalism is commonly observed in marine species. For instance, intrabrood cannibalism has been documented in marine gastropods with direct development, suggesting a relationship between embryo behavior and the evolution of life history strategies. However, there has been little effort to document the factors driving sibling cannibalism in marine species. The kin selection theory suggests that the level of relatedness plays an important role in cannibalism patterns. We examined Crepidula coquimbensis, a marine gastropod that broods and encloses its brooded offspring in capsules. Encapsulated embryos show sibling cannibalism and high levels of intracapsular multiple paternity. Given these features, cannibalistic behavior may be driven by kin-relatedness. To test this hypothesis, we constructed artificial aggregations of embryos to mimic three levels of relatedness: high, medium and low. For each category of aggregation, the cannibalism rate and benefits (i.e. size at hatching of surviving offspring) were estimated. In addition, at the end of embryo development, we performed parentage analyses to determine if cannibalism was associated with the relatedness between cannibal and victim embryos. Our results show that the intensity of sibling cannibalism increased in aggregations characterized by the lowest level of relatedness. There were important benefits of cannibalism in terms of hatching cannibal size. In addition, cannibalism between embryos was not random: the variation in reproductive success between males increased over the course of the experiment and the effective number of fathers decreased. Altogether, these results suggest that polyandry may play an important role in the evolution of sibling cannibalism in C. coquimbensis and that kin selection may operate during early embryonic stages in this species. [ABSTRACT FROM AUTHOR]

Abstract: Multiple mating and sperm storage organs allow postcopulatory sexual selection to occur. This is the first time that a paternity test has been performed in an earthworm species. Microsatellite markers are used in Hormogaster elisae to trace paternity for multiple sires. Multiple paternity was detected in some cases, showing sperm mixture even within one cocoon, suggesting the eventual mixture of the allosperm within the spermathecae. Order of copulation influences paternity, the first (P1) and third partner (P3) being the most successful. Interestingly the second partner (P2) almost lacks paternity. The most plausible hypothesis suggests the existence of sperm displacement by flushing out older sperm once the spermathecae are full, which seems to occur when they contain sperm from two partners and P3 donates. At that moment sperm is still stratified thus removing sperm from P2. Afterwards sperm from P1 and P3 would be mixed provoking an equivalent paternity. Given the endogeic nature of the earthworm, copulation was not observed, making the lack of copulation with P2 (due to the need of a recovery time) or copulation without sperm transfer (due to low sperm production rate) possible alternative hypotheses. The weight of the earthworms is related to the number of cocoons they produce but not to their viability, which in all the cases was low, probably due to laboratory conditions. The sperm was kept viable inside the spermathecae for a maximum of two years and three months, suggesting a very effective nourishment system in the epithelium of the storage structures. [Copyright &y& Elsevier]

Population density might be an important variable in determining the degree of multiple paternity. In a previous study, a high level of multiple paternity was detected in the shiner perch Cymatogaster aggregata, a species with high population density and a high mate encounter rate. The tule perch Hysterocarpus traski is phylogenetically closely related to C. aggregata, but it has relatively lower population density, which may result in distinct patterns of multiple paternity in these 2 species. To test the hypothesis that mate encounter rate may affect the rate of successful mating, we used polymorphic microsatellite markers to identify multiple paternity in the progeny arrays of 12 pregnant females from a natural population of tule perch. Multiple paternity was detected in 11 (92%) of the 12 broods. The number of sires per brood ranged from 1 to 4 (mean 2.5) but with no correlation between sire number and brood size. Although the brood size of tule perch is considerably larger than that of shiner perch (40.7 vs. 12.9, respectively), the average number of sires per brood in tule perch is much lower than that in shiner perch (2.5 vs. 4.6, respectively). These results are consistent with the hypothesis that mate encounter rate is an important factor affecting multiple mating. [ABSTRACT FROM PUBLISHER]

Microsatellite markers were used to investigate the mating system of the Estuarine Crocodile (Crocodylus porosus). Three-hundred and eighty-six hatchlings from 13 clutches from a wild Northern Territory population, and 364 hatchlings from 21 clutches from a captive North Queensland population, were sampled. All samples were genotyped across five microsatellite loci. Multiple paternity was found in 69% of clutches in the wild population compared to 38% of clutches in the captive population. Up to three possible fathers were indicated in some clutches. Shared paternity was suggested by the presence of a common paternal genotype within two clutches in the wild population and among up to three clutches from a large shared pen in the captive population. The probability of detecting multiple paternity at all loci was high; 95% in the wild population and 98% in the captive population. There was no evidence of increased hatching success in the clutches that indicated multiple paternity compared to single paternity clutches in either population (P = 0.43 to P = 0.67). It is unknown whether the occurrence of multiple paternity in C. porosus is a result of multiple mating within the same breeding season or of sperm stored from matings in a previous season. These results suggest the genetic mating system for C. porosus is not polygynous but more likely promiscuous, and there is no evidence of dominant alpha males who control paternity in large areas. [ABSTRACT FROM AUTHOR]

Abstract: Multiple paternity within the same clutch has been detected in all sea turtle species. However, no study to date has addressed the likelihood of sperm storage across years in any sea turtle species in the wild because of the logistical difficulties associated with investigating the same individual females across breeding seasons. Here we provide paternity data from captive loggerhead turtles (Caretta caretta) during 2–4 successive breeding seasons and behavioral information to estimate sperm storage duration in this species. Data from interseasonal comparisons for individual females showed that paternity was identical between two successive breeding seasons. However, females were observed to copulate with males, which were sire of their hatchlings of the previous breeding season, just prior to the nesting period of the next breeding season. Therefore, it is appropriate to regard the consistency in paternity across two successive breeding seasons as a result of re-mating with a sire from the previous season. Conversely, paternity was entirely different from that in the previous season if copulatory behavior occurred just prior to the next season with a male that was not a sire of the female''s hatchlings from the previous season. Furthermore, a female that had laid fertile eggs in the previous breeding season but was not observed to successfully copulate with any male during the next breeding season laid no fertile eggs during that next season. Taking these data into consideration, it appears that sperm storage across breeding seasons did not occur in this study of captive Caretta. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

The family is an arena for conflicts between offspring, mothers and fathers that need resolving to promote the evolution of parental care and the maintenance of family life. Co-adaptation is known to contribute to the resolution of parent–offspring conflict over parental care by selecting for combinations of offspring demand and parental supply that match to maximize the fitness of family members. However, multiple paternity and differences in the level of care provided by mothers and fathers can generate antagonistic selection on offspring demand (mediated, for example, by genomic imprinting) and possibly hamper co-adaptation. While parent–offspring co-adaptation and parental antagonism are commonly considered two major processes in the evolution of family life, their co-occurrence and the evolutionary consequences of their joint action are poorly understood. Here, we demonstrate the simultaneous and entangled effects of these two processes on outcomes of family interactions, using a series of breeding experiments in the European earwig, Forficula auricularia, an insect species with uniparental female care. As predicted from parental antagonism, we show that paternally inherited effects expressed in offspring influence both maternal care and maternal investment in future reproduction. However, and as expected from the entangled effects of parental antagonism and co-adaptation, these effects critically depended on postnatal interactions with caring females and maternally inherited effects expressed in offspring. Our results demonstrate that parent–offspring co-adaptation and parental antagonism are entangled key drivers in the evolution of family life that cannot be fully understood in isolation. [ABSTRACT FROM AUTHOR]

While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders. [ABSTRACT FROM AUTHOR]

Abstract: The African wild dog (Lycaon pictus) is an endangered exotic canid with less than 5500 animals remaining in the wild. Despite numerous strategies to conserve this species, numbers of free-living animals are in decline. It is a highly social species with a complex pack structure: separate male and female dominant hierarchies with, typically, participation of subdominant adults in the rearing of the dominant breeding pairs’ pups. Basic reproductive knowledge is largely missing in this species, with only limited information available on the profile of reproductive hormones, based on non-invasive endocrine monitoring. The dominant or alpha male and female are reproductively active and the subdominants are generally reproductively suppressed. However, the occasional production of litters by subdominant females and evidence of multiple paternity within litters suggests that fertility of subordinates is not completely inhibited. In this respect, there are still considerable gaps in our knowledge about the mechanisms governing reproduction and reproductive suppression in African wild dogs, particularly the influence of dominance and pack structure on both male and female fertility. Given concerns over the long-term survival of this species, further research in this area is essential to provide valuable information for their captive breeding and conservation. Reproductive information can also be applied to the development of Assisted Reproductive Techniques for this species; the utility of which in African wild dog conservation is also discussed. [Copyright &y& Elsevier]

Rates of multiple paternities were investigated in the sailfin molly (Poecilia latipinna), using eight microsatellite loci. Genotyping was performed for offspring and mothers in 40 broods from four allopatric populations from the south-eastern U.S.A. along a geographic stretch of 1200 km in west-east direction and approximately 200 km from north to south. No significant differences regarding rates of multiple paternities were found between populations despite sample populations stemming from ecologically divergent habitats. Even the most conservative statistical approach revealed a minimum of 70% of the broods being sired by at least two males, with an average of 1.80-2.95 putative fathers per brood. Within broods, one male typically sired far more offspring than would be expected under an assumed equal probability of all detected males siring offspring. [ABSTRACT FROM AUTHOR]

The imbalanced reproductive success of polygynous mammals results in sexual selection on male traits like body size. Males and females might have more balanced reproductive success under polygynandry, where both sexes mate multiply. Using 4 years of microsatellite DNA analyses of paternity and known maternity, we investigated variation in reproductive success of Columbian ground squirrels, Urocitellus columbianus (Ord, 1815); a species with multiple mating by both sexes and multiple paternity of litters. We asked whether male reproductive success was more variable than that of females under this mating system. The overall percentage of confirmed paternity was 61.4% of 339 offspring. The mean rate of multiple paternity in litters with known fathers was 72.4% ( n = 29 litters). Estimated mean reproductive success of males (10.27 offspring) was about thrice that of females (3.11 offspring). Even after this difference was taken into account statistically, males were about three times as variable in reproductive success as females (coefficients of variation = 77.84% and 26.74%, respectively). The Bateman gradient (regression slope of offspring production on number of successful mates) was significantly greater for males ( βM = 1.44) than females ( βF = 0.28). Thus, under a polygynandrous mating system, males exhibited greater variation in reproductive success than females. [ABSTRACT FROM AUTHOR]