8,685 research outputs found

    Mating Frequency of European Corn Borer (Lepidoptera: Crambidae) in Minnesota, Kansas, and Texas

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    The frequency of mating and polyandry in natural populations are important parameters for understanding evolutionary dynamics. Mating frequency among natural populations of Ostrinia nubilalis (Hübner) [Lepidoptera: Crambidae] are quite variable. Showers et al. (1974) found 91.1, 73.8, and 71.3% of females had mated during the second flight over 1971-3 at one location in Iowa. During 1971, only 10% mated multiple times, with lower levels of polyandry in subsequent years. In an earlier study in Iowa, Pesho (1961) found that 65-100 % of females had mated and up to 43% had mated more than once. A population in southwestern Ontario averaged 73% mating and 37% polyandry for the 5-year period from 1971-5, a higher rate of polyandry than during the same period in Iowa (Elliot, 1977). In this note, we amplify these previously published results by reporting the mating status of female O. nubilalis captured in light traps in Minnesota, Kansas and Texas. We also provide evidence that some females in natural populations may be sperm-limited

    Larger testes are associated with a higher level of polyandry, but a smaller ejaculate volume, across bushcricket species (Tettigoniidae)

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    While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate ( ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate

    Evolution of female multiple mating : A quantitative model of the “sexually selected sperm” hypothesis

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    This article is protected by copyright. All rights reserved. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Peer reviewedPublisher PD

    When does female multiple mating evolve to adjust inbreeding? : Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait

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    Ackowledgements: This work was funded by a European Research Council Starting Grant to JMR. All simulations were performed using the Maxwell computing cluster at the University of AberdeenPeer reviewedPublisher PD

    Evolution of precopulatory and post-copulatory strategies of inbreeding avoidance and associated polyandry

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    Acknowledgments This work was funded by a European Research Council Starting Grant to JMR. Computer simulations were performed using the Maxwell Computing Cluster at the University of Aberdeen. We thank Matthew E. Wolak and two anonymous reviewers for very helpful comments.Peer reviewedPublisher PD

    Mating system and population genetic structure of the bulldog ant Myrmecia pavida

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    Understanding the evolution of the alternative mating strategies of monandry and polyandry is a fundamental problem in evolutionary biology because of the cost-benefit trade-offs associated with mating for females. The problem is particularly intriguing in the social insects because queens in most species appear to be obligately monandrous (i.e., only a single male fathers their offspring), while those in a minority of species have evolved high, and sometimes extreme, polyandry. One group which may shed particular insight is the ant subfamily Myrmeciinae (Myrmecia and Nothomyrmecia). Here we examine the population and colony genetic structure of the bulldog ant Myrmecia pavida CLARK, 1951 by genotyping offspring workers from 45 colonies. We find little evidence of geographic structuring or inbreeding in the population, indicating that the species outbreeds, most probably in mating swarms. We also find that queens of M pavida show moderately high polyandry, with 84% having mated with between two and seven males, and an overall mean observed mating frequency of 3.8. This is significantly higher than previously reported for queens of Nothomyrmecia macrops, in which most females mate singly. This was similar to that of M pyriformis, M brevinoda, and M pilosula, the three congenerics for which mating frequencies have recently been reported. The two genera in the Myrmeciinae therefore appear to show multiple transitions in mating frequency and further investigation of the subfamily may be highly informative for disentangling the forces driving the evolution of alternative mating strategies

    Dogging Cornwall’s 'secret freaks': Béroul on the limits of European orthodoxy

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    This piece argues that Béroul's version of the Tristan tale can be read as offering a discreetly veiled view of the sexual, ritual and ontological chaos associated with visions of the Celtic West such as figure in Gerald of Wales' History and Topography of Ireland as well as with accounts of heretical orgies found in continental sources such as Caesarius of Heisterbach. Drawing parallels between the poem’s fictional Cornwall and Gerald’s often hyperbolically lurid accounts of the perversions and peculiarities of Ireland, both religious and sexual, this essay targets the cultural voyeurism in which the world of King Mark appears to veil its kinship with the deviance and hybridity Gerald presents as characteristic of religious life across the Irish Sea. This relation can perhaps helpfully be characterised as a form of cultural 'dogging', the sociology of which is one of the methodological focuses of this paper and which mirrors Béroul's recurring focus on voyeuristic scenarios. Evidently, however, the disavowed investments underlying orthodoxy's voyeuristic fascination with what Gerald describes as the'secret freaks' nature spawns in Ireland also reflect a desire to render unintelligible the logics of othered practices. What gives Béroul’s text an edginess discernible even today is the clear implication that such ‘flawed’ societies operated on their own cultural terms and according to the

    Multiple paternity and hybridization in two smooth-hound sharks

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    Multiple paternity appears to be a common trait of elasmobranch mating systems, with its occurrence likely driven by convenience, due to females seeking to minimize the stress of male harassment. Here we use molecular markers to analyse the frequency of multiple paternity in two related viviparous sharks, Mustelus mustelus and Mustelus punctulatus. We first applied molecular methods to assign pregnant females, embryos and additional reference adults (N\u2009=\u2009792) to one of the two species. Paternity analysis was performed using a total of 9 polymorphic microsatellites on 19 females and 204 embryos of M. mustelus, and on 13 females and 303 embryos of M. punctulatus. Multiple paternity occurs in both species, with 47% of M. mustelus and 54% of M. punctulatus litters sired by at least two fathers. Female fecundity is not influenced by multiple mating and in 56% of polyandrous litters paternity is skewed, with one male siring most of the pups. Genetic analyses also revealed hybridization between the two species, with a M. punctulatus female bearing pups sired by a M. mustelus male. The frequency of polyandrous litters in these species is consistent with aspects of their reproductive biology, such as synchronous ovulation and possible occurrence of breeding aggregations

    A genetic assessment of parentage in the blackspot sergeant damselfish, Abudefduf sordidus (Pisces: Pomacentridae)

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    Microsatellite markers were used to investigate the reproductive behavior of the damselfish Abudefduf sordidus at Johnston Atoll, Central Pacific Ocean. Genetic results indicated that ten males maintained guardianship over their nest territories for up to nine nest cycles during a 3.5 month period. Genotypes of 1025 offspring sampled from 68 nests (composed of 129 clutches) were consistent with 95% of the offspring being sired by the guardian male. Offspring lacking paternal alleles at two or more loci were found in 19 clutches, indicating that reproductive parasitism and subsequent alloparental care occurred. Reconstructed maternal genotypes allowed the identification of a minimum of 74 different females that spawned with these ten territorial males. Males were polygynous, mating with multiple females within and between cycles. Genetic data from nests, which consisted of up to four clutches during a reproductive cycle, indicated that each clutch usually had only one maternal contributor and that different clutches each had different dams. Females displayed sequential polyandry spawning with one male within a cycle but switched males in subsequent spawning cycles. These results highlight new findings regarding male parasitic spawning, polygyny, and sequential polyandry in a marine fish with exclusive male paternal care.Published versio
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