Overt and covert competition in a promiscuous mammal: the importance of weaponry and testes size to male reproductive success

Preston, Brian T.; Stevenson, Ian R.; Pemberton, Josephine M.; Coltman, David W.; Wilson, Kenneth

doi:10.1098/rspb.2002.2268

Cited by 296 publications

(252 citation statements)

References 41 publications

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“…For example, primate sexual swellings are associated with multi-male mating and promiscuity . Testes mass is also associated with mating group size and promiscuity (Harcourt et al, 1981;Preston et al, 2003). Promiscuity and larger mating group sizes facilitate mucosal contact and transmission of microbes among many mating partners, whereas perineal swellings increase the length and volume of the vagina, and consequently increase exposure to microbes.…”

Section: Discussionmentioning

confidence: 99%

Primate vaginal microbiomes exhibit species specificity without universal Lactobacillus dominance

et al. 2014

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Bacterial communities colonizing the reproductive tracts of primates (including humans) impact the health, survival and fitness of the host, and thereby the evolution of the host species. Despite their importance, we currently have a poor understanding of primate microbiomes. The composition and structure of microbial communities vary considerably depending on the host and environmental factors. We conducted comparative analyses of the primate vaginal microbiome using pyrosequencing of the 16S rRNA genes of a phylogenetically broad range of primates to test for factors affecting the diversity of primate vaginal ecosystems. The nine primate species included: humans (Homo sapiens), yellow baboons (Papio cynocephalus), olive baboons (Papio anubis), lemurs (Propithecus diadema), howler monkeys (Alouatta pigra), red colobus (Piliocolobus rufomitratus), vervets (Chlorocebus aethiops), mangabeys (Cercocebus atys) and chimpanzees (Pan troglodytes). Our results indicated that all primates exhibited host-specific vaginal microbiota and that humans were distinct from other primates in both microbiome composition and diversity. In contrast to the gut microbiome, the vaginal microbiome showed limited congruence with host phylogeny, and neither captivity nor diet elicited substantial effects on the vaginal microbiomes of primates. Permutational multivariate analysis of variance and Wilcoxon tests revealed correlations among vaginal microbiota and host species-specific socioecological factors, particularly related to sexuality, including: female promiscuity, baculum length, gestation time, mating group size and neonatal birth weight. The proportion of unclassified taxa observed in nonhuman primate samples increased with phylogenetic distance from humans, indicative of the existence of previously unrecognized microbial taxa. These findings contribute to our understanding of host-microbe variation and coevolution, microbial biogeography, and disease risk, and have important implications for the use of animal models in studies of human sexual and reproductive diseases.

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Section: Discussionmentioning

confidence: 99%

Primate vaginal microbiomes exhibit species specificity without universal Lactobacillus dominance

et al. 2014

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“…As suggested above (examples 2, 7), some morphological traits may be subject to stabilizing sexual selection: for example, combat success may be maximized with a particular relative weapon size (Clutton-Brock 1982; Kitchener 2000; but see Preston et al 2001Preston et al , 2003, multiple mechanisms of sexual selection may exert conflicting selection on a trait (Moore and Moore 1999;Bonduriansky and Rowe 2003), or sexual and viability selection may balance (e.g., Wilkinson 1987). Our model suggests that selection on the trait size to body size ratio per se produces isometric scaling (example 2), while more complex functions that yield net stabilizing selection on trait size (example 7) may produce other allometric patterns.…”

Section: Discussionmentioning

confidence: 99%

The Evolution of Static Allometry in Sexually Selected Traits

2003

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Abstract. Although it has been the subject of verbal theory since Darwin, the evolution of morphological trait allometries remains poorly understood, especially in the context of sexual selection. Here we present an allocation trade-off model that predicts the optimal pattern of allometry under different selective regimes. We derive a general solution that has a simple and intuitive interpretation and use it to investigate several examples of fitness functions. Verbal arguments have suggested cost or benefit scenarios under which sexual selection on signal or weapon traits may favor larger individuals with disproportionately larger traits (i.e., positive allometry). However, our results suggest that this is necessarily true only under a precisely specified set of conditions: positive allometry will evolve when the marginal fitness gains from an increase in relative trait size are greater for large individuals than for small ones. Thus, the optimal allometric pattern depends on the precise nature of net selection, and simple examples readily yield isometry, positive or negative allometry, or polymorphisms corresponding to sigmoidal scaling. The variety of allometric patterns predicted by our model is consistent with the diversity of patterns observed in empirical studies on the allometries of sexually selected traits. More generally, our findings highlight the difficulty of inferring complex underlying processes from simple emergent patterns.Key words. Allometry, display traits, evolution, exaggerated traits, morphology, sexual selection, signaling, weapons.Received April 7, 2003. Accepted June 5, 2003 An organism's shape is defined by the sizes of its body parts (traits) in relation to the size of the whole (body size), with the scaling pattern relating trait size to body size known as the trait allometry. Although a great deal of work has been devoted to the mathematical analysis of observed allometric patterns (e.g., Brody 1945;Gould 1966;Sprent 1972;Eberhard and Gutiérrez 1991) and the effects of biomechanical constraints (e.g., McMahon 1975;Pennycuick 1992;Ravosa et al. 2000), much less is known about how allometry is shaped by selection. This last question is of particular interest in the context of sexually selected traits, which sometimes exhibit spectacular elaboration and enlargement (e.g., Darwin 1871;Gould 1974;Simmons and Tomkins 1996;Emlen and Nijhout 2000). In this paper, we use a resource allocation trade-off model to investigate how the form of selection acting on a trait and body size affects the evolution of static allometry, trait scaling with body size among conspecific individuals at the same developmental stage (Cock 1966). The model yields some intuitively appealing predictions as well as counterintuitive insights that challenge the validity or generality of verbal theories.Allometries are usually modeled using the allometric equation (Brody 1945), Y ϭ aX b . When log-transformed, this becomes the linear equation log(Y) ϭ log(a) ϩ blog(X), where b is the allometric slope. Although, in pra...

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“…The reason for this is unclear but horn base circumference may have experienced greater sexually antagonistic selection than horn length. While most studies of sexual selection in sheep have focused on male horn length (for example, Coltman et al, 2002;Preston et al, 2003), there is no obvious reason to expect sexual selection to act on horn length more than horn base circumference. Horn base circumference is likely more important than horn length for fighting because males clash their horns near the base.…”

Section: Discussionmentioning

confidence: 99%

QTL mapping for sexually dimorphic fitness-related traits in wild bighorn sheep

et al. 2011

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Dissecting the genetic architecture of fitness-related traits in wild populations is key to understanding evolution and the mechanisms maintaining adaptive genetic variation. We took advantage of a recently developed genetic linkage map and phenotypic information from wild pedigreed individuals from Ram Mountain, Alberta, Canada, to study the genetic architecture of ecologically important traits (horn volume, length, base circumference and body mass) in bighorn sheep. In addition to estimating sex-specific and cross-sex quantitative genetic parameters, we tested for the presence of quantitative trait loci (QTLs), colocalization of QTLs between bighorn sheep and domestic sheep, and sexÂQTL interactions. All traits showed significant additive genetic variance and genetic correlations tended to be positive. Linkage analysis based on 241 microsatellite loci typed in 310 pedigreed animals resulted in no significant and five suggestive QTLs (four for horn dimension on chromosomes 1, 18 and 23, and one for body mass on chromosome 26) using genome-wide significance thresholds (Logarithm of odds (LOD) 43.31 and 41.88, respectively). We also confirmed the presence of a horn dimension QTL in bighorn sheep at the only position known to contain a similar QTL in domestic sheep (on chromosome 10 near the horns locus; nominal Po0.01) and highlighted a number of regions potentially containing weight-related QTLs in both species. As expected for sexually dimorphic traits involved in male-male combat, loci with sex-specific effects were detected. This study lays the foundation for future work on adaptive genetic variation and the evolutionary dynamics of sexually dimorphic traits in bighorn sheep.

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Overt and covert competition in a promiscuous mammal: the importance of weaponry and testes size to male reproductive success

Cited by 296 publications

References 41 publications

Primate vaginal microbiomes exhibit species specificity without universal Lactobacillus dominance

Primate vaginal microbiomes exhibit species specificity without universal Lactobacillus dominance

The Evolution of Static Allometry in Sexually Selected Traits

QTL mapping for sexually dimorphic fitness-related traits in wild bighorn sheep

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