01966nas a2200193   4500008004100000245013500041210006900176300001200245490000800257520123000265653001901495653001601514653001401530653002101544653002201565100002401587700002301611856013801634       2003                        eng d00aGenital morphology and fertilization success in the dung beetle Onthophagus taurus: an example of sexually selected male genitalia0 aGenital morphology and fertilization success in the dung beetle   a447-4550 v2703 aIn 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 hypoth- esis. 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. 10amale genitalia10aOnthophagus10apaternity10asexual selection10aSperm competition1 aHouse, Clarissa, M.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/genital-morphology-and-fertilization-success-dung-beetle-onthophagus-taurus-example-sexually-selecte02439nas a2200217   4500008004100000245014600041210006900187300001400256490000700270520159300277653003101870653002401901653002201925653002101947653003001968653002301998653001502021100002402036700002302060856013802083       2005                        eng d00aThe evolution of male genitalia: patterns of genetic variation and covariation in the genital sclerites of the dung beetle Onthophagus taurus0 aevolution of male genitalia patterns of genetic variation and co  a1281-12920 v183 aThree main hypotheses, have been invoked to explain divergent genital evolution, the lock and key, pleiotropy, and sexual selection hypotheses, each of which make different predictions about how genital traits are inherited. Here we used a half-sib breeding design to examine the patterns of genetic variation and covariation between male genital sclerites, and their covariance with general body morphology in the dung beetle Onthophagus taurus. We found CVA’s and CVP’s were similar for both genital and general morphological traits and that CVR’s were large for both trait types. We found that male genital sclerites were negatively genetically correlated with general morphological traits. Variation in male genital morphology has direct implications for a male’s fertilization success and the resulting sexual selection acting on male genitalia is predicted to maintain high levels of additive genetic variance. Contrary to this prediction, we found that individual genital sclerites all had low levels of additive genetic variance and large maternal and environmental sources of variation. Our data suggest that the genital sclerites in O. taurus are not inherited independently but as a genetically integrated unit. More import- antly, the way the different sclerites function to influence male fertilization success reflects this genetic integration. Even though levels of VA in individual genital sclerites may be low, there may still be sufficient VA in multivariate trait space for selection to generate evolutionary change in the overall morphology of male genitalia. 10aadditive genetic variation10agenetic correlation10agenital evolution10amaternal effects10amorphological integration10aOnthophagus taurus10apleiotropy1 aHouse, Clarissa, M.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/evolution-male-genitalia-patterns-genetic-variation-and-covariation-genital-sclerites-dung-beetle-on01741nas a2200193   4500008004100000245011700041210006900158300001200227490000700239520101400246653001901260653001901279653001901298653002301317653002201340100002401362700002301386856013801409       2006                        eng d00aOffensive and defensive sperm competition roles in the dung beetle Onthophagus taurus (Coleoptera: Scarabaeidea)0 aOffensive and defensive sperm competition roles in the dung beet  a131-1360 v603 aSperm competition is predicted to generate op- posing selection pressures on males. On one hand, selec- tion should favour ‘defensive’ adaptations that protect a male’s ejaculate from displacement, while, on the other hand, selection should favour ‘offensive’ adaptations that overcome paternity assurance mechanisms of rivals. Here, we use the sterile male technique to assess sperm pre- cedence when a male dung beetle Onthophagus taurus mates in both a defensive (first male) and an offensive (second male) role. Significant variation in a male’s sperm precedence (both P1 and P2) was detected, and an individual’s defensive (P1) and offensive (P2) abilities were positively correlated. Thus, it appears that sexual selection simultaneously selects for ‘defensive’ and ‘of- fensive’ adaptations in O. taurus. We discuss a variety of male traits in O. taurus that potentially contribute to a male’s ability to be successful whenmatinginan‘of-fensive’ and a ‘defensive’ role. 10aDefensive role10amale genitalia10aOffensive role10aOnthophagus taurus10aSperm competition1 aHouse, Clarissa, M.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/offensive-and-defensive-sperm-competition-roles-dung-beetle-onthophagus-taurus-coleoptera-scarabaeid00732nas a2200193   4500008004100000245011900041210006900160260000800229300001200237490000700249653001700256653002600273653002200299653002300321653002100344100001500365700002300380856013500403       1997                        eng d00aPatterns of fluctuating asymmetry in beetle horns: an experimental examination of the honest signalling hypothesis0 aPatterns of fluctuating asymmetry in beetle horns an experimenta  cmay  a109-1140 v4110abeetle horns10afluctuating asymmetry10ahonest signalling10aOnthophagus taurus10asexual selection1 aHunt, John1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/patterns-fluctuating-asymmetry-beetle-horns-experimental-examination-honest-signalling-hypothesis01698nas a2200301   4500008004100000245013300041210006900174300001200243490000700255520067200262653001400934653001300948653001600961653001600977653002600993653001301019653001801032653001901050653001001069653002001079653001601099653006201115653002501177653001801202100001501220700002301235856013801258       1998                        eng d00aPatterns of parental provisioning covary with male morphology in a horned beetle (Onthophagus taurus) (Coleoptera: Scarabaeidae)0 aPatterns of parental provisioning covary with male morphology in  a447-4510 v423 aMale dung beetles, Onthophagus taurus, are dimorphic for a secondary sexual trait, head horns. Horned males participate in the production of brood masses while hornless male do not. Here we examine the reproductive performance of females mated with males exhibiting alternative horn morphologies. We found that exposure to males may be costly for females in that it reduced the total number of brood masses produced. However, females paired with horned males produced significantly larger brood masses than females paired with hornless males or females producing broods alone. We discuss the possible selection pressures that may underly horn evolution in this genus.10aAnimalia-10aAnimals-10aArthropoda-10aArthropods-10aColeoptera-: Insecta-10aInsects-10aInvertebrata-10aInvertebrates-10amale-10amale-dimorphism10amorphology-10aOnthophagus-taurus [horned-beetle] (Coleoptera-): female-10aparental-care-patter10aReproduction-1 aHunt, John1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/patterns-parental-provisioning-covary-male-morphology-horned-beetle-onthophagus-taurus-coleoptera-sc02368nas a2200181   4500008004100000245016000041210006900201300001200270490000700282520162100289653003101910653002801941653002301969653001801992100001502010700002302025856013802048       2002                        eng d00aConfidence of paternity and paternal care: covariation revealed through the experimental manipulation of the mating system in the beetle Onthophagus taurus0 aConfidence of paternity and paternal care covariation revealed t  a784-7950 v153 aTheoretical models of paternal care predict that facultative reductions in male care may occur under certain conditions. One important parameter that has been shown to influence the outcome of these models is a male’s confidence of paternity. In this study, we tested whether the amount of care provided by horned males in the dimorphic beetle, Onthophagus taurus, varied with his confidence of paternity. Male care results in an increased weight of dung provided in the brood masses produced by the pair. Using the sterile male technique we showed that a horned male’s paternity declined with the number of sneak males in the population. The relationship was nonlinear, with paternity declining most rapidly between a frequency of one and three sneaks, and stabilizing thereafter at about 50%. A horned male’s paternity was directly related to the number of copulations with the female, relative to the number of copulations achieved by sneaks. Horned males were shown to reduce their care in relation to their declining paternity. Video analysis demonstrated that reductions in male care occurred through a combination of male desertion and a trade-off between caring and paternity assurance behaviours. The number of fights with sneak males was negatively related to the amount of care provided by a horned male. These results suggest that by gauging his expected paternity through the number of fights with sneaks, a horned male is able to assess his paternity and reduce his investment accordingly. Our data thus provide strong empirical support for the proposed link between paternity and paternal care. 10aalternative mating tactics10aconfidence of paternity10aOnthophagus taurus10apaternal care1 aHunt, John1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/confidence-paternity-and-paternal-care-covariation-revealed-through-experimental-manipulation-mating02257nas a2200145   4500008004100000245012200041210006900163260001100232300001400243490000700257520167200264100001501936700002301951856013701974       2002                        eng d00aThe genetics of maternal care: direct and indirect genetic effects on phenotype in the dung beetle Onthophagus taurus0 agenetics of maternal care direct and indirect genetic effects on  cmay 14  a6828-68320 v993 aWhile theoretical models of the evolution of parental care are based on the assumption of underlying genetic variance, surpris- ingly 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 con- siderably 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. 1 aHunt, John1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/genetics-maternal-care-direct-and-indirect-genetic-effects-phenotype-dung-beetle-onthophagus-taurus03021nas a2200205   4500008004100000245007100041210006900112300001200181490000700193520235800200653002002558653002302578653003402601653001802635653002102653653000702674100001502681700002302696856009602719       2004                        eng d00aOptimal maternal investment in the dung beetle Onthophagus taurus?0 aOptimal maternal investment in the dung beetle Onthophagus tauru  a302-3120 v553 aOptimal investment theory is based on the assumption that the proximate constraint acting on parental investment is resource based. A trade-off between per offspring investment and total investment seems intuitive. Consequently, a parent’s investment strategy is expected to represent a trade-off between the benefits of investment for current offspring and the costs to future reproduction for parents. In this study, we provide clear evidence that the costs and benefits of maternal provisioning in the dung beetle Onthophagus taurus influence the amount of provisions provided by the mother. Horse dung is typically of a higher nutritional value than cow dung and females were shown to provide 20% less dung to offspring when provisioning with horse dung. By reducing their investment per offspring and exhibiting a clear preference to provision offspring with horse dung, females were able to produce significantly more offspring. Females provisioning with horse dung received greater fitness returns per unit of investment and experienced lower provisioning costs, in terms of the minimum amount of dung required to produce a surviving offspring, than females provisioning with cow dung. Females provisioning in soil of low moisture content were found to have higher tunneling costs than those provi- sioning in soil of high moisture content, while the fitness returns per unit of investment did not differ. We adopted a marginal value theorem (MVT) approach to calculate the theoretical optimal level of investment for each dung type and for each soil moisture. Predicted levels of provision- ing were lower for horse dung than for cow dung and for moist soil than for dry soil. Therefore, the results of this study are in qualitative agreement with MVT predictions and provide empirical support for the proposal that females can adaptively adjust their level of investment in response to resource and/or habitat quality. However, the theoretically predicted optimal investment yielded a poor quantitative fit with our observed levels of investment, with females providing over twice the investment predicted by the MVT approach. We suggest that this difference may reflect either our inability in directly quantifying all the necessary costs and benefits of investment in O. taurus and/or the applicability of the underlying assumptions of MVT.10aHabitat quality10aOnthophagus taurus10aOptimal investment strategies10aParental care10aResource quality10a·1 aHunt, John1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/optimal-maternal-investment-dung-beetle-onthophagus-taurus01696nas a2200277   4500008004100000245010400041210006900145300001200214490000800226520076300234653002700997653001401024653001301038653001601051653001601067653001401083653001001097653002601107653001801133653003701151653004501188653001801233100002301251700002301274856012101297       2001                        eng d00aEffects of Macrocheles mites on longevity of males of the dimorphic dung beetle Onthophagus binodis0 aEffects of Macrocheles mites on longevity of males of the dimorp  a441-4450 v2543 aIn this study we tested the nature of the phoretic relationship between the cosmopolitan mite Macrocheles merdarius and the dimorphic dung beetle Onthophagus binodis. We observed and experimentally manipulated the number of mites on individual beetles and tested how mite infestation affects male longevity. There was a significant effect of mites on male longevity: males in our mites-added treatment died on average 15 days earlier than males in our mites-removed treatment. Interestingly, the number of mites on males was significantly repeatable suggesting that individuals may differ in their susceptibility to infestation. Major males had more mites on them than minor males, and the proportion of mites on minor males was negatively density dependent.10aAcarina-: Chelicerata-10aAnimalia-10aAnimals-10aArthropoda-10aArthropods-10aBehavior-10aCheli10aColeoptera-: Insecta-10aInvertebrata-10aMacrocheles-merdarius (Acarina-)10aOnthophagus-binodis (Coleoptera-): male-10aParasitology-1 aKotiaho, Janne, S.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/effects-macrocheles-mites-longevity-males-dimorphic-dung-beetle-onthophagus-binodis02616nas a2200253   4500008004100000245006900041210006900110300001200179490000600191520178900197653003501986653002402021653002802045653001902073653002102092653001602113653003102129653002502160100002202185700001502207700002302222700002302245856009402268       2002                        eng d00aThreshold evolution in exotic populations of a polyphenic beetle0 aThreshold evolution in exotic populations of a polyphenic beetle  a587-6010 v43 aPolyphenic development is thought to play an important role in the evolution of phenotypic diversity and morphological novelties, yet the evolution of polyphenisms has rarely been docu- mented in natural populations. Here we compare the morphologies of male dung beetles (Onthophagus ttaurus; Coleoptera: Scarabaeidae) from populations introduced to Australia and the eastern United States. Males in this species express two alternative morphologies in response to larval feeding conditions. Males encountering favourable conditions grow larger than a threshold body size and develop a pair of horns on their heads, whereas males that encounter poor conditions do not reach this threshold size and remain hornless. Australian and US populations did not differ in overall body size ranges, but exhibited significant differences in the location of the critical body size threshold that separates alternative male morphs. Australian males remained hornless at much larger body sizes than males in US populations, resulting in substantial and significant differences in the average body size–horn length allometry between exotic populations, as well as significant differences in morph ratios. The phenotypic divergence observed between field populations was maintained in laboratory populations after two generations under identical environmental conditions, suggesting a genetic basis to allometric divergence in these populations. Divergence between exotic O. taurus populations was of a magnitude and kind typically observed between species. We use our results to examine potential causes of allometric divergence in onthophagine beetles, and discuss the evolutionary potential of threshold traits and polyphenic development in the origin of morphological and behavioural diversity.10aadaptive phenotypic plasticity10aalternative tactics10adevelopmental threshold10aexotic species10ahorn polyphenism10aOnthophagus10astatus-dependent selection10athreshold evolution.1 aMoczek, Armin, P.1 aHunt, John1 aEmlen, Douglas, J.1 aSimmons, Leigh, W.  uhttps://scarabnet.myspecies.info/threshold-evolution-exotic-populations-polyphenic-beetle