101
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Genetic analysis of parentage within experimental populations of a male dimorphic beetle, Onthophagus taurus, using amplified fragment length polymorphism. Behav Ecol Sociobiol 2004. [DOI: 10.1007/s00265-004-0843-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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102
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Roff DA, Sokolovska N. Extra-nuclear effects on growth and development in the sand cricket Gryllus firmus. J Evol Biol 2004; 17:663-71. [PMID: 15149408 DOI: 10.1046/j.1420-9101.2003.00673.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although largely ignored until recently, parental effects on the phenotypes of their offspring are both ubiquitous in nature and of a potentially great importance to evolution. Our study examines the presence of extra-nuclear (maternal and paternal) effects in growth traits, development time and adult size in the sand cricket Gryllus firmus using a diallel cross of inbred lines. Sex linkage was shown to be nonsignificant for development time but the other traits could not be tested. We assume that they are nonsignificant but use the term 'reciprocal' effects to include this effect. We show that reciprocal effects are present in the growth traits and development time, where they account for 10-30% of the phenotypic variance. They are not present in adult size as indexed by head width. We demonstrate that reciprocal effects are due, at least in part, to maternal effects by an analysis of the positive correlation between egg size, a maternal trait, and the growth traits. The growth rate traits show no significant decline with age either with respect to extra-nuclear contributions to variance or difference between phenotypic means of reciprocal pairs. This study demonstrates that extra-nuclear effects are important contributors to the phenotypic variation in life history traits of G. firmus.
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Affiliation(s)
- D A Roff
- Department of Biology, University of California, Riverside, CA, USA.
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103
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Aubin-Horth N, Dodson JJ. INFLUENCE OF INDIVIDUAL BODY SIZE AND VARIABLE THRESHOLDS ON THE INCIDENCE OF A SNEAKER MALE REPRODUCTIVE TACTIC IN ATLANTIC SALMON. Evolution 2004. [DOI: 10.1554/03-256] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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104
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105
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Kotiaho JS, Simmons LW, Hunt J, Tomkins JL. Males influence maternal effects that promote sexual selection: a quantitative genetic experiment with dung beetles Onthophagus taurus. Am Nat 2003; 161:852-9. [PMID: 12858271 DOI: 10.1086/375173] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2002] [Accepted: 10/10/2002] [Indexed: 11/03/2022]
Abstract
Recently, doubt has been cast on studies supporting good genes sexual selection by the suggestion that observed genetic benefits for offspring may be confounded by differential maternal allocation. In traditional analyses, observed genetic sire effects on offspring phenotype may result from females allocating more resources to the offspring of attractive males. However, maternal effects such as differential allocation may represent a mechanism promoting genetic sire effects, rather than an alternative to them. Here we report results from an experiment on the horned dung beetle Onthophagus taurus, in which we directly compare genetic sire effects with maternal effects that are dependent on sire phenotype. We found strong evidence that mothers provide more resources to offspring when mated with large-horned males. There were significant heritabilities for both horn length and body size, but when differential maternal effects were controlled, the observed estimates of genetic variance were greatly reduced. Our experiment provides evidence that differential maternal effects may amplify genetic effects on offspring traits that are closely related to fitness. Thus, our results may partly explain the relatively high coefficients of additive genetic variation observed in fitness-related traits and provide empirical support for the theoretical argument that maternal effects can play an important role in evolution.
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Affiliation(s)
- Janne S Kotiaho
- Department of Zoology, University of Western Australia, Nedlands, Western Australia 6009, Australia
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106
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Affiliation(s)
- James M Cheverud
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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107
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House CM, Simmons LW. Genital morphology and fertilization success in the dung beetle Onthophagus taurus: an example of sexually selected male genitalia. Proc Biol Sci 2003; 270:447-55. [PMID: 12641898 PMCID: PMC1691274 DOI: 10.1098/rspb.2002.2266] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In animals with internal fertilization and promiscuous mating, male genitalia show rapid and divergent evolution. Three hypotheses have been suggested to explain the evolutionary processes responsible for genital evolution: the lock-and-key hypothesis, the pleiotropy hypothesis and the sexual-selection hypothesis. Here, we determine whether variation in male genital morphology influences fertilization success in the dung beetle Onthophagus taurus, as predicted by the sexual-selection hypothesis. Variation in four out of five genital sclerites of the endophallus influenced a male's fertilization success, supporting the general hypothesis that male genitalia can evolve under sexual selection. Furthermore, different genital sclerites were found to enhance first versus second male paternity, indicating that different sclerites serve offensive and defensive roles. Genital-trait variability was comparable to that in other species but was less variable than a non-genital sexually selected trait (head horns). We suggest that directional selection for genital elaboration may be countered by natural selection, which should favour genitalia of a size and shape necessary for efficient coupling and sperm transfer.
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Affiliation(s)
- Clarissa M House
- Evolutionary Biology Research Group, Department of Zoology, University of Western Australia, Nedlands, WA 6009, Australia.
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108
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Garant D, Dodson JJ, Bernatchez L. DIFFERENTIAL REPRODUCTIVE SUCCESS AND HERITABILITY OF ALTERNATIVE REPRODUCTIVE TACTICS IN WILD ATLANTIC SALMON (SALMO SALAR L). Evolution 2003. [DOI: 10.1554/0014-3820(2003)057[1133:drsaho]2.0.co;2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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109
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Hunt J, Simmons LW. Confidence of paternity and paternal care: covariation revealed through the experimental manipulation of the mating system in the beetle
Onthophagus taurus. J Evol Biol 2002. [DOI: 10.1046/j.1420-9101.2002.00442.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- J. Hunt
- Evolutionary Biology Research Group, Department of Zoology, The University of Western Australia, Nedlands, Western Australia, Australia
| | - L. W. Simmons
- Evolutionary Biology Research Group, Department of Zoology, The University of Western Australia, Nedlands, Western Australia, Australia
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110
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111
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Hunt J, Simmons LW. The genetics of maternal care: direct and indirect genetic effects on phenotype in the dung beetle Onthophagus taurus. Proc Natl Acad Sci U S A 2002; 99:6828-32. [PMID: 11983863 PMCID: PMC124488 DOI: 10.1073/pnas.092676199] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While theoretical models of the evolution of parental care are based on the assumption of underlying genetic variance, surprisingly few quantitative genetic studies of this life-history trait exist. Estimation of the degree of genetic variance in parental care is important because it can be a significant source of maternal effects, which, if genetically based, represent indirect genetic effects. A major prediction of indirect genetic effect theory is that traits without heritable variation can evolve because of the heritable environmental variation that indirect genetic effects provide. In the dung beetle, Onthophagus taurus, females provide care to offspring by provisioning a brood mass. The size of the brood mass has pronounced effects on offspring phenotype. Using a half-sib breeding design we show that the weight of the brood mass females produce exhibits significant levels of additive genetic variance due to sires. However, variance caused by dams is considerably larger, demonstrating that maternal effects are also important. Body size exhibited low additive genetic variance. However, body size exerts a strong maternal influence on the weight of brood masses produced, accounting for 22% of the nongenetic variance in offspring body size. Maternal body size also influenced the number of offspring produced but there was no genetic variance for this trait. Offspring body size and brood mass weight exhibited positive genetic and phenotypic correlations. We conclude that both indirect genetic effects, via maternal care, and nongenetic maternal effects, via female size, play important roles in the evolution of phenotype in this species.
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Affiliation(s)
- John Hunt
- Evolutionary Biology Research Group, Department of Zoology, University of Western Australia, Nedlands, WA 6907, Australia.
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112
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Rauter CM, Moore AJ. Evolutionary importance of parental care performance, food resources, and direct and indirect genetic effects in a burying beetle. J Evol Biol 2002. [DOI: 10.1046/j.1420-9101.2002.00412.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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113
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Simmons LW, Kotiaho JS. EVOLUTION OF EJACULATES: PATTERNS OF PHENOTYPIC AND GENOTYPIC VARIATION AND CONDITION DEPENDENCE IN SPERM COMPETITION TRAITS. Evolution 2002. [DOI: 10.1554/0014-3820(2002)056[1622:eoepop]2.0.co;2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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114
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115
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Rauter CM, Moore AJ. QUANTITATIVE GENETICS OF GROWTH AND DEVELOPMENT TIME IN THE BURYING BEETLE NICROPHORUS PUSTULATUS IN THE PRESENCE AND ABSENCE OF POST-HATCHING PARENTAL CARE. Evolution 2002. [DOI: 10.1554/0014-3820(2002)056[0096:qgogad]2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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116
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Hunt J, Simmons LW. Status-dependent selection in the dimorphic beetle Onthophagus taurus. Proc Biol Sci 2001; 268:2409-14. [PMID: 11747558 PMCID: PMC1088894 DOI: 10.1098/rspb.2001.1758] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The occurrence of alternative reproductive phenotypes is widespread in most animal taxa. The majority of known examples best fit the notion of alternative tactics within a conditional strategy where the fitness pay-offs depend on an individual's competitive ability or status. Individuals are proposed as "choosing" the tactic that maximizes their fitness, given their status relative to others in the population. Theoretically, status-dependent selection should determine when an animal should switch between alternative tactics. While a number of studies have demonstrated unequal fitness pay-offs associated with alternative tactics, none, to our knowledge, have examined the fitness functions necessary for predicting when individuals should switch between tactics. Here, we use a dimorphic male beetle in order to provide the first empirically derived fitness function across alternative reproductive phenotypes. Our data provide empirical support for a game-theoretic conditional strategy that has evolved under status-dependent selection.
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Affiliation(s)
- J Hunt
- Evolutionary Biology Research Group, Department of Zoology,The University of Western Australia, Nedlands, Western Australia 6907, Australia.
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117
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Abstract
Maternal and paternal effects can lead to complicated evolutionary dynamics, including evolution in the opposite direction to selection. Recent studies demonstrate that parental effects on sexually selected traits, as well as preferences for those traits, might be large. Although these findings are likely to have consequences for both the evolutionary dynamics and equilibria of sexual selection, theory is lacking. Because parents are expected to maximize their own fitness, rather than that of a specific offspring, the magnitude (and even direction) of parental effects are context dependent. By extension, this dynamic nature of parental effects might help to explain the maintenance of variation in many sexually selected traits.
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