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M. Fitzgerald - One of the best experts on this subject based on the ideXlab platform.
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Variation in Mating Systems and sexual size dimorphism between populations of the Australian python Morelia spilota (Serpentes: Pythonidae)
Oecologia, 1995Co-Authors: R. Shine, M. FitzgeraldAbstract:Although adaptationist hypotheses predict a functional relationship between Mating Systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in Mating Systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished records, we document intraspecific geographic variation in Mating Systems (presence versus absence of male-male combat) within the widely-distributed Australian python Morelia spilota . Radiotelemetric monitoring of 19 free-ranging pythons in a population in north-eastern New South Wales showed that these animals display a Mating system of female defence polygyny. Previous studies on a southern population of the same species found that males engaged in long mate-searching movements, showed no overt agonistic behavior, and formed long-term (>2 months) aggregations around reproductive females. In strong contrast, our adult male carpet pythons (i) moved about relatively little (mean displacement
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variation in Mating Systems and sexual size dimorphism between populations of the australian python morelia spilota serpentes pythonidae
Oecologia, 1995Co-Authors: R. Shine, M. FitzgeraldAbstract:Although adaptationist hypotheses predict a functional relationship between Mating Systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in Mating Systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished records, we document intraspecific geographic variation in Mating Systems (presence versus absence of male-male combat) within the widely-distributed Australian python Morelia spilota. Radiotelemetric monitoring of 19 free-ranging pythons in a population in north-eastern New South Wales showed that these animals display a Mating system of female defence polygyny. Previous studies on a southern population of the same species found that males engaged in long mate-searching movements, showed no overt agonistic behavior, and formed long-term (>2 months) aggregations around reproductive females. In strong contrast, our adult male carpet pythons (i) moved about relatively little (mean displacement <11 m/day) during the Mating season, (ii) remained with females only briefly (<5 days), and (iii) engaged in male-male combat in the vicinity of females. This male-male combat included vigorous biting as well as ritualised "wrestling" matches, resulting in a high incidence of bite scars in adult males. In keeping with predictions from sexual selection theory, males attain larger body sizes than females in this population, whereas females grow larger than males in the previously-studied southern population where males do not engage in physical combat for Mating opportunities.
R. Shine - One of the best experts on this subject based on the ideXlab platform.
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Variation in Mating Systems and sexual size dimorphism between populations of the Australian python Morelia spilota (Serpentes: Pythonidae)
Oecologia, 1995Co-Authors: R. Shine, M. FitzgeraldAbstract:Although adaptationist hypotheses predict a functional relationship between Mating Systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in Mating Systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished records, we document intraspecific geographic variation in Mating Systems (presence versus absence of male-male combat) within the widely-distributed Australian python Morelia spilota . Radiotelemetric monitoring of 19 free-ranging pythons in a population in north-eastern New South Wales showed that these animals display a Mating system of female defence polygyny. Previous studies on a southern population of the same species found that males engaged in long mate-searching movements, showed no overt agonistic behavior, and formed long-term (>2 months) aggregations around reproductive females. In strong contrast, our adult male carpet pythons (i) moved about relatively little (mean displacement
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variation in Mating Systems and sexual size dimorphism between populations of the australian python morelia spilota serpentes pythonidae
Oecologia, 1995Co-Authors: R. Shine, M. FitzgeraldAbstract:Although adaptationist hypotheses predict a functional relationship between Mating Systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in Mating Systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished records, we document intraspecific geographic variation in Mating Systems (presence versus absence of male-male combat) within the widely-distributed Australian python Morelia spilota. Radiotelemetric monitoring of 19 free-ranging pythons in a population in north-eastern New South Wales showed that these animals display a Mating system of female defence polygyny. Previous studies on a southern population of the same species found that males engaged in long mate-searching movements, showed no overt agonistic behavior, and formed long-term (>2 months) aggregations around reproductive females. In strong contrast, our adult male carpet pythons (i) moved about relatively little (mean displacement <11 m/day) during the Mating season, (ii) remained with females only briefly (<5 days), and (iii) engaged in male-male combat in the vicinity of females. This male-male combat included vigorous biting as well as ritualised "wrestling" matches, resulting in a high incidence of bite scars in adult males. In keeping with predictions from sexual selection theory, males attain larger body sizes than females in this population, whereas females grow larger than males in the previously-studied southern population where males do not engage in physical combat for Mating opportunities.
John C. Avise - One of the best experts on this subject based on the ideXlab platform.
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1984 DNA Fingerprinting and Mating Systems
Conceptual Breakthroughs in Evolutionary Genetics, 2014Co-Authors: John C. AviseAbstract:Mating Systems are what they seem. Mating Systems (such as monogamy, polygyny, polyandry, polygynandry, and promiscuity) traditionally were assessed by field observations of who mated with whom (or, in plants, by monitoring pollinator movements). This kind of information was difficult to obtain (especially for secretive species) and at best yielded only the “social Mating system” of a population. Ideally, however, researchers would like to know the genetic Mating system because this would reveal who actually had mated with whom to transmit genes to the next generation. In the 1960s, the deployment of protein-electrophoretic methods for the first time enabled evolutionary biologists to begin to assess genetic parentage (maternity and paternity) based on molecular polymorphisms in nature, and thereby characterize a population’s actual genetic Mating system. The general approach involved comparing multi-locus genotypes of candidate parents against those of progeny in focal broods, and then accumulating such information for multiple clutches in each population of interest. In 1984, a related breakthrough was the invention of methods for “DNA fingerprinting” based on hypervariable “minisatellite” regions of eukaryotic genomes.
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genetic perspectives on the natural history of fish Mating Systems
Journal of Heredity, 2001Co-Authors: J A Dewoody, John C. AviseAbstract:Molecular analyses of bird and mammal populations have shown that social Mating Systems must be distinguished from genetic Mating Systems. This distinction is important in fishes also, where the potential for extrapair spawning and intraspecific brood parasitism is especially great. We review studies on fishes that have used molecular markers to document biological parentage and genetic Mating Systems in nature, particularly in species with extended parental care of offspring. On average, nest-guarding adults parented about 70-95% of their custodial offspring, and approximately one-third of the nests were cuckolded to some extent. Furthermore, nearly 10% of the assayed nests contained offspring tended by foster fathers either because of nest takeovers or egg thievery. On average, fish that provide parental care on nests spawned with more mates than did fish with internal fertilization and pregnancy. Overall, genetic markers have both confirmed and quantified the incidence of several reproductive and other social behaviors of fishes, and have thereby enhanced our knowledge of piscine natural history.
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turtle Mating Systems behavior sperm storage and genetic paternity
Journal of Heredity, 2001Co-Authors: Devon E Pearse, John C. AviseAbstract:As evidenced by the articles in this volume, a recent increase in interest in the Mating Systems of poikilothermic vertebrates has focused primarily on fishes, a few amphibians, and squamate reptiles. Turtles by contrast have received relatively little attention, yet they display a wide variety of Mating behaviors and life-history characteristics that make them excellent candidates for addressing several aspects of genetic parentage that should contribute to a broader understanding of animal reproductive strategies. Here we focus on genetic studies of the Mating Systems and reproductive patterns of turtles, specifically with respect to multiple paternity and long-term sperm storage. These phenomena highlight the importance of a temporally extended perspective on patterns of individual reproductive success.
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Mating Systems and sexual selection in male pregnant pipefishes and seahorses insights from microsatellite based studies of maternity
Journal of Heredity, 2001Co-Authors: Adam Jones, John C. AviseAbstract:In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic Mating Systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic Mating Systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic Mating Systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the Mating system than previously available techniques. Finally, these genetic studies of syngnathid Mating Systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.
Trevor E. Pitcher - One of the best experts on this subject based on the ideXlab platform.
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Evolution of Mating Systems and sexual size dimorphism in North American cyprinids
Behavioral Ecology and Sociobiology, 2013Co-Authors: Mark Pyron, Trevor E. Pitcher, Stephen J. JacqueminAbstract:Mating Systems evolve with sexual size dimorphism (SSD) in many animals. Mating Systems with males larger than females occur when males compete for female access or guard territories, while Mating Systems with group Mating tend to occur in species where females are the same size or larger than males. In addition to variation in SSD with Mating system, sperm competition varies among Mating Systems in predictable patterns. We examined the evolution of Mating Systems with SSD and testes mass in 111 North American Cyprinidae fishes using phylogenetic comparative methods. Our results demonstrate that the evolution of Mating Systems in Cyprinidae fishes is from ancestral taxa that are group spawners with females the same size or larger than males to pair spawning Systems where males tend to be larger than females. We used an additive model to predict male and female body size from testes mass and Mating system. Only Mating system varied predictably with SSD. Our results for analyses of hyperallometry (Rensch’s rule) were that individual species of Cyprinidae can have hyperallometry for SSD, but the pattern is not present across all taxa.
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Mating Systems, SPERM COMPETITION, AND THE EVOLUTION OF SEXUAL DIMORPHISM IN BIRDS
Evolution, 2007Co-Authors: Peter O. Dunn, Linda A. Whittingham, Trevor E. PitcherAbstract:Comparative analyses suggest that a variety of factors influence the evolution of sexual dimorphism in birds. We analyzed the relative importance of social Mating system and sperm competition to sexual differences in plumage and body size (mass and tail and wing length) of more than 1000 species of birds from throughout the world. In these analyses we controlled for phylogeny and a variety of ecological and life-history variables. We used testis size (corrected for total body mass) as an index of sperm competition in each species, because testis size is correlated with levels of extrapair paternity and is available for a large number of species. In contrast to recent studies, we found strong and consistent effects of social Mating system on most forms of dimorphism. Social Mating system strongly influenced dimorphism in plumage, body mass, and wing length and had some effect on dimorphism in tail length. Sexual dimorphism was relatively greater in species with polygynous or lekking than monogamous Mating Systems. This was true when we used both species and phylogenetically independent contrasts for analysis. Relative testis size was also related positively to dimorphism in tail and wing length, but in most analyses it was a poorer predictor of plumage dimorphism than social Mating system. There was no association between relative testis size and mass dimorphism. Geographic region and life history were also associated with the four types of dimorphism, although their influence varied between the different types of dimorphism. Although there is much interest in the effects of sperm competition on sexual dimorphism, we suggest that traditional explanations based on social Mating Systems are better predictors of dimorphism in birds.
A. F. Dixson - One of the best experts on this subject based on the ideXlab platform.
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Primate Mating Systems and the evolution of immune response
Journal of Reproductive Immunology, 2004Co-Authors: M.j Anderson, J.k Hessel, A. F. DixsonAbstract:White blood cell (WBC) and red blood cell (RBC) counts were examined in a sample comprising 762 specimens, representing 25 genera and 38 species of captive non-human primates. Animals suffering from illnesses exhibited higher WBC counts than healthy specimens sampled during routine health checks. Analysis of basal WBC counts in healthy animals confirmed a positive correlation between higher cell counts and occurrences of multiple partner Mating. This finding remained statistically significant after use of comparative analysis of independent contrasts (CAIC) to control for possible phylogenetic biases in the dataset. These findings were confirmed when using relative testis size as an independent index of Mating system. By contrast, RBC counts were not significantly affected by health or correlated with Mating Systems. These studies confirm a correlation between WBC counts and primate Mating Systems, and extend the findings to include a positive correlation between WBC counts and relative testis size. However, the findings do not prove that a causal relationship between these variables exists. Further research is required to establish the evolutionary causation of basal WBC counts in primates.
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Testes weight, body weight and Mating Systems in marsupials and monotremes
Journal of Zoology, 1997Co-Authors: R. W. Rose, C. M. Nevison, A. F. DixsonAbstract:Relationships between testes weight, body weight and Mating Systems were examined in 40 marsupial species and in the extant monotremes. Relationships between relative testes weight and Mating Systems in marsupials resemble those previously described for primates. Thus relative testes weights are greatest in those marsupials where females mate with multiple males during the fertile period, i.e. polyandrous species (e.g. Antechinus flavipes, Isoodorr obesulus, Peranzetes nasuta, Potorous tridactylus, Macropus eugenii and M. agilis) and smallest in monandrous forms (e.g. Petauroides volans and Petaurus breviceps) where females usually mate with a single male. These findings are consistent with effects of sperm competition upon the evolution of relative testes sizes in marsupials. Where field studies on marsupial Mating Systems are lacking, we make predictions based upon examination of their relative testes weights. Tarsipes rostratus, Acrobates pygmaeus, Macropus rufogriseus and Sarcophilus harrisii are predicted to engage in multiple Matings and sperm competition. Conversely, Lasiorhinus latifrons, Cercatetus concinnus and Pseudoantechinus macdonnellensis are predicted to be monandrous in their Mating hehaviour. The monotremes (Ornithorhynchus anatinus, Tachyglossus aculeatus and Zaglossus bruijnii) are characterized by possession of very large testes; monotremes are shown to have significantly greater relative testes weights than marsupials, primates or avian species. This taxonomic difference is unlikely to be related 10 the occurrence of oviparity or to the abdominal position of the testes in the Monotremata. Their Mating Systems are not known in detail, but some evidence for multiple Matings (and hence for sperm competition) exists for Tachyglossus aculeatus so that their large testes may be adaptive in this context.