Multiple Paternity

Mating in the marsupial genus Antechinus is a synchronous annual event that is characterized by monoestry in females and abrupt postmating mortality in males. Male semelparity (multiple copulations during a single breeding season per lifetime) is often assumed to occur as a consequence of the intense mating effort expended by males in the rut, but the forces selecting for this remain elusive. Here, we investigate selection in male brown antechinus, Antechinus stuartii, and test two hypotheses for the evolution of semelparity: intermale competition and sperm competition. If intermale competition drives semelparity, we predicted that males would be under strong selection for large body size. If sperm competition is important, we predicted that selection would be strongest on scrotal size, a surrogate for testes volume. Using microsatellite markers, we found that 92% of females in free‐living conditions mated with multiple males, producing litters of eight that had up to four fathers. ...

ABSTRACTHistorically, behavior studies have focused mainly on animals of two phyla in particular: Craniata and Arthropoda, however, behavioral research on alternative phyla like mollusks has been increasing because of the potential for research that these models present. When we talk about mollusk behavior, cephalopods are the first group that stands out, however, research on Mexico’s endemic species likeOctopus maya, is still lacking. This octopus could help to reach a standardized model in neuroscience, because adapts well to laboratory conditions and has been successfully cultured through several generations. These characteristics provide a great advantage as a research model since they could reduce the number of variables that affect behavioral studies, something hard to control with a captured-wild octopus. Hence, in order to work properly with species like this, in research environments, it’s fundamental to know first the behaviors that this species can perform there. Therefor...

A fifth of all species in the carnivorous‐insectivorous marsupial family Dasyuridae show obligate male semelparity (die‐off), where males die after their first mating season, but females may breed in more than one season. Life history strategies of many species in the genera Antechinus and Phascogale are well known, but the other dasyurid genus with apparently obligately semelparous males, Dasykaluta, is poorly known, and there have been no demographic studies of this monotypic genus in the wild. Both sexes in Antechinus and Phascogale species are highly polygamous. Comparative and experimental tests of insectivorous marsupials indicate that this polygamy is linked to the evolution of semelparity in more strongly seasonal breeders, through intense sperm competition. We assessed whether the kaluta (Dasykaluta rosamondae), a small dasyurid endemic to the broader Pilbara region of Western Australia, has obligate male semelparity, multiple paternity within litters, and positive testis a...

Background Raising unrelated offspring is typically wasteful of parental resources and so individuals are expected to reduce or maintain low levels of parental effort when their parentage is low. This can involve facultative, flexible adjustments of parental care to cues of lost parentage in the current brood, stabilizing selection for a low level of paternal investment, or an evolutionary reduction in parental investment in response to chronically low parentage. Results We studied parental care in Variabilichromis moorii, a socially monogamous, biparental cichlid fish, whose mating system is characterized by frequent cuckoldry and whose primary form of parental care is offspring defense. We combine field observations with genetic parentage analyses to show that while both parents defend their nest against intruding con- and hetero-specifics, males and females may do so for different reasons. Males in the study group (30 breeding pairs) sired 0–100% (median 83%) of the fry in their ...

In several animal taxa, genetic analyses have demonstrated that social monogamy and biparental brood care do not preclude polygamous reproduction. Few studies have been conducted in fish, but in fish species without alternative reproductive phenotypes, social monogamy was largely congruent with genetic parentage. In contrast to these findings, we report an exceptionally high level of multiple paternity in a socially monogamous cichlid fish with biparental nest defence (Variabilichromis moorii), inferred from microsatellite and mitochondrial data of 10 broods. Whereas all offspring in a nest shared a common mother, each brood was sired by 2 to > 10 males. None of the inferred sires was assigned a large proportion of the brood. Paternity was estimated as the minimum number of sires required to explain multilocus offspring genotypes, and as the maximum‐likelihood number of sires given population allele frequencies. Analysis of simulated brood genotypes suggested that, although these...

Many marine species are under high fishing pressure, which can cause alterations in their mating systems and the structure of their populations. The spiny spider crab Maja brachydactyla is a commercial decapod on the east Atlantic coast. In Galicia, the most exploited region in Spain, the landing of ovigerous females is prohibited, favouring exploitation focused on males. The removal of males, especially the largest ones, may lead to sperm limitation and a reduction in the average size over generations. In these cases, polyandry can work as a mechanism to protect females against sperm limitation and to increase genetic diversity and effective population size. This study analyses the multiple paternity in M. brachydactyla in two localities that differ in female fecundity, fishing intensity, and management measures. Our results showed multiple paternity in this species for the first time, with a moderate bias between sires. However, the frequency of multiple paternity was almost seven...

Supported by evidence for assortative mating and polygynandry, sexual selection through mate choice was suggested as the main force driving the evolution of colour diversity of haplochromine cichlids in Lakes Malawi and Victoria. The phylogenetically closely related tribe Tropheini of Lake Tanganyika includes the genus Tropheus , which comprises over 100 colour variants currently classified into six morphologically similar, polyphyletic species. To assess the potential for sexual selection in this sexually monochromatic maternal mouthbrooder, we used microsatellite-based paternity inference to investigate the mating system of Tropheus moorii . In contrast to haplochromines in Lake Malawi, multiple paternity is rare or even absent in broods of T. moorii . Eighteen of the 19 analysed families were consistent with genetic monogamy, while either a mutation or more than one sire explained the genotype of one offspring in another brood. We discuss the differences in breeding behaviour bet...

Males exhibit striking variation in the degree to which they invest in offspring, from merely provisioning females with sperm, to providing exclusive post‐zygotic care. Paternity assurance is often invoked to explain this variation: the greater a male's confidence of paternity, the more he should be willing to provide care. Here, we report a striking exception to expectations based on paternity assurance: despite high levels of female promiscuity, males of a marine snail provide exclusive, and costly, care of offspring. Remarkably, genetic paternity analyses reveal cuckoldry in all broods, with fewer than 25% of offspring being sired by the caring male, although caring males sired proportionally more offspring in a given clutch than any other fathers did individually. This system presents the most extreme example of the coexistence of high levels of female promiscuity, low paternity, and costly male care, and emphasises the still unresolved roles of natural and sexual selection ...

The Squalus genus comprises a group of small demersal sharks occurring circumglobally, popularly known as dogfish sharks. This genus exhibits a conserved morphology, thus making correct morphological identification difficult. Considering these taxonomic problems and the scarcity of molecular data, the present study aimed to identify Squalus genus MOTUs, using DNA barcoding for species delimitation via ABGD (automatic barcode gap discovery), PTP (Poisson tree process), and GMYC (general mixed Yule coalescent) employing the mitochondrial COI gene. A total of 69 sequences were generated from samples obtained from the American coast in both the Atlantic and Pacific Oceans. The ABGD analysis was the most conservative among the three applied delimitations, indicating three taxonomic units, while the PTP analysis revealed nine MOTUs, with two conflicting units noted between S. clarkae + S. mitsukurii and S. albicaudus + S. cubensis. The GMYC analysis indicated an excessive division, with S...

Prairie voles (Microtus ochrogaster (Wagner, 1842)) exhibit behavioral, morphological, and neuroendocrinological traits associated with monogamy and are considered a model system to examine the biological foundations of monogamy in mammals. We examined allelic polymorphism at microsatellite loci to assess mating exclusivity in wild prairie voles sampled in east-central Illinois and found evidence of multiple paternity in five of nine litters (56%) analyzed. Thus, a female in this socially monogamous mammal with extensive mechanisms for pair bonding does not always mate solely with its partner and raises the paradox of why some pair-bonded females mate multiply.