scholarly journals Do extra-group fertilizations increase the potential for sexual selection in male mammals?

2017 ◽  
Vol 13 (10) ◽  
pp. 20170313 ◽  
Author(s):  
Kavita Isvaran ◽  
Sumithra Sankaran
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Uniform Distribution ◽  
Mating Systems ◽  
Fertilization Success ◽  
Comparative Methods ◽  
Phylogenetic Comparative Methods ◽  
Trait Evolution ◽  
The Social ◽  
Measures Of Inequality

Fertilizations by males outside the social breeding group (extra-group paternity, EGP) are widespread in birds and mammals. EGP is generally proposed to increase male reproductive skew and thereby increase the potential for sexual selection, but the generality of this relationship is unclear. We extracted data from 27 mammals in seven orders and used phylogenetic comparative methods to investigate the influence of EGP and social mating system on measures of inequality in male fertilization success, which are indices of the potential for sexual selection. We find that EGP and social mating system can predict the potential for sexual selection in mammalian populations, but only when considered jointly and not individually. EGP appears to increase the potential for sexual selection but only when the degree of social polygyny is relatively low. When social polygyny is high, EGP appears to result in a more uniform distribution of reproduction and a decrease in the potential for sexual selection. A possible explanation to be investigated is that the phenotype of extra-group fathers differs systematically across social mating systems. Our findings have implications for the use of EGP and social mating system as indices of sexual selection in comparative analyses of trait evolution under sexual selection.

scholarly journals Ecological correlates of extra-group paternity in mammals

2006 ◽  
Vol 274 (1607) ◽  
pp. 219-224 ◽  
Author(s):  
Kavita Isvaran ◽  
Tim Clutton-Brock
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Interspecific Variation ◽  
Comparative Methods ◽  
Phylogenetic Comparative Methods ◽  
Mating Season ◽  
Breeding Group ◽  
Ecological Correlates ◽  
Present Understanding

Extra-group paternity (EGP) can form an important part of the mating system in birds and mammals. However, our present understanding of its extent and ecology comes primarily from birds. Here, we use data from 26 species and phylogenetic comparative methods to explore interspecific variation in EGP in mammals and test prominent ecological hypotheses for this variation. We found extensive EGP (46% of species showed more than 20% EGP), indicating that EGP is likely to play an important role in the mating system and the dynamics of sexual selection in mammals. Variation in EGP was most closely correlated with the length of the mating season. As the length of the mating season increased, EGP declined, suggesting that it is increasingly difficult for males to monopolize their social mates when mating seasons are short and overlap among females in oestrus is likely to be high. EGP was secondarily correlated with the number of females in a breeding group, consistent with the idea that as female clustering increases, males are less able to monopolize individual females. Finally, EGP was not related to social mating system, suggesting that the opportunities for the extra-group fertilizations and the payoffs involved do not consistently vary with social mating system.

2. Mating systems, or who goes with whom, and for how long

2018 ◽  
pp. 16-33
Author(s):  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Social Relationships ◽  
Breeding Season ◽  
Mating Systems ◽  
Practical Applications ◽  
Multiple Partners ◽  
Monogamous Species ◽  
Genetic Techniques ◽  
Males And Females

‘Mating systems, or who goes with whom, and for how long’ examines the variation in how males and females associate during the breeding season, ranging from brief couplings with multiple partners to lifelong monogamy. It also shows how the discovery that females mate with many partners, even in supposedly monogamous species such as songbirds, was made possible by modern genetic techniques. Variation in mating systems holds considerable implications for the operation of sexual selection. The way that animal mating systems have been explained historically is outlined before considering how a more contemporary understanding of genetic and social relationships has reshaped our thinking and how understanding a species’ mating system can have practical applications.

scholarly journals Endless forms of sexual selection

2019 ◽  
Author(s):  
Willow R Lindsay ◽  
Staffan Andersson ◽  
Badreddine Bererhi ◽  
Jacob Höglund ◽  
Arild Johnsen ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Mate Choice ◽  
Sexual Conflict ◽  
Genetic Architecture ◽  
Mating Systems ◽  
Population Divergence ◽  
Trait Evolution ◽  
Mating Competition ◽  
Mhc Genes

The field of sexual selection has burgeoned with research into trait evolution in the context of ecology, sociality, phylogeny, natural selection, and sexual conflict. This paper is the product of a “stock-taking” workshop; our aim is to stimulate discussion, not to provide an exhaustive review. We identify outstanding questions organized into four thematic sections. 1) Evolution of mate choice and mating systems. Variation in mate quality can generate mating competition and choice in either sex with implications for the evolution of mating systems. Limitations on mate choice may dictate the importance of direct vs. indirect benefits in mating decisions and consequently, mating systems. Specifically, polyandry evolves in response to the strength of pre- vs. post-copulatory selection. The evolution of polyandry may be related to diversity of pathogens and Major Histocompatibility Complex (MHC) genes. MHC genes are also potential cues of kinship in avoidance of inbreeding. The balance between inbreeding avoidance and inclusive fitness in mating decisions deserves greater attention. 2) Sender and receiver mechanisms shaping signal design. Mediation of honest signal content likely depends on integration of temporally variable social and physiological costs that are a challenge to measure. The neuroethology of sensory and cognitive receiver biases is the main key to signal form and the ‘aesthetic sense’ proposed by Darwin. Since a receiver bias is sufficient to both start and drive ornament or armament exaggeration, without a genetically correlated or even coevolving receiver, this may be the appropriate ‘null model’ of sexual selection. 3) Genetic architecture of sexual selection. Despite advances in modern molecular techniques, the number and identity of genes underlying performance remain largely unknown. A combination of genomic techniques and long-term field studies that reveal ecological correlates of reproductive success is warranted. In-depth investigations into the genetic basis of sexual dimorphism will reveal constraints and trajectories of sexually selected trait evolution. 4) Sexual selection and conflict as drivers of speciation. Population divergence and speciation is often driven by an interplay between sexual and natural selection. To what extent sexual selection promotes or counteracts population divergence may differ depending on the genetic architecture of traits as well as covariance between mating competition and local adaptation, if traits have multiple functions and if sensory systems used in mate choice are locally adapted. Also, post-copulatory processes, e.g. selection against heterospecific sperm, may influence the importance of sexual selection. Sexual conflict can shape speciation processes, since mate choice selection on females can restrict gene flow whereas selection on males is permissive. We propose that efforts to resolve these four themes can catalyze conceptual progress in the field of sexual selection.

Evolution of Animal Mating Systems

2021 ◽  
Author(s):  
Ingrid Ahnesjö ◽  
Luc Bussière
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Evolutionary Biology ◽  
Mating Systems ◽  
Multiple Mating ◽  
Mating Strategies ◽  
Secondary Sexual Traits ◽  
Mating System Evolution ◽  
Before And After ◽  
Patterns And Processes

Animal mating systems are fascinating and diverse, and their evolution is central to evolutionary biology. A mating system describes patterns and processes of how females and males mate and reproduce successfully, and how this relates to their reproductive ecologies, including demographic and environmental factors. One of the more stimulating challenges in biology is to provide a comprehensive explanation for the evolution of mating adaptations among animals. In the course of sexual reproduction, animals engage in a dizzying array of traits, behaviors, and strategies. Such diversity simultaneously requires and eludes categorization: it is required for a general understanding, but at once confounds any rigorous classification because an almost inexhaustible supply of animal examples disrupt otherwise neatly ordered systems (see Classifications of Animal Mating Systems). Historically, mating with a single partner was thought to be a common mating system among animals. However, increasing observations of multiple mating by both sexes, supported by genomic evidence of mixed parentage within families, has since revealed that strict genetic monogamy is rare. In this bibliography, the selected literature highlights a compelling diversity and flexibility among animal mating systems, and sexual selection emerges both as a contributing cause and consequence of this variation. Sexual selection plays a central role in animal mating system evolution, and key references provide insights into its operation before and after mating, and describe how it leads to the expression of secondary sexual traits and sexual conflicts. Efforts to explain diversity in animal mating systems have often focused on how acquiring mates or matings relates to variance in reproductive success. This variation and diversity can be approached at the level of an individual, among individuals in a population, or between species. However, a preoccupation with the mean or average pattern often leads to generalizations that obscure important diversity crucial to evolutionary understanding. To avoid unnecessary categorization, the presentation here focus`es on variation in mating patterns and contrasts multiple mating with mating with a single partner. Furthermore, it considers the wider effects of animal mating systems, and includes associations with patterns of parental care. The aim with this bibliography is to provide key citations demonstrating that animal mating systems evolve from diverse, interactive, complex and dynamic processes resulting in a variety of adaptive mating strategies in females and males. A grateful acknowledgment is given to C. Kvarnemo and D. Gwynne for insightful comments.

scholarly journals Beyond Brownian motion and the Ornstein-Uhlenbeck process: Stochastic diffusion models for the evolution of quantitative characters

2016 ◽  
Author(s):  
Simon Phillip Blomberg
Keyword(s):  
Brownian Motion ◽  
Stochastic Processes ◽  
Comparative Methods ◽  
Diffusion Models ◽  
Mathematical Framework ◽  
Phylogenetic Comparative Methods ◽  
Uhlenbeck Process ◽  
Trait Evolution ◽  
Ornstein Uhlenbeck Process ◽  
Non Gaussian

AbstractGaussian processes such as Brownian motion and the Ornstein-Uhlenbeck process have been popular models for the evolution of quantitative traits and are widely used in phylogenetic comparative methods. However, they have drawbacks which limit their utility. Here I describe new, non-Gaussian stochastic differential equation (diffusion) models of quantitative trait evolution. I present general methods for deriving new diffusion models, and discuss possible schemes for fitting non-Gaussian evolutionary models to trait data. The theory of stochastic processes provides a mathematical framework for understanding the properties of current, new and future phylogenetic comparative methods. Attention to the mathematical details of models of trait evolution and diversification may help avoid some pitfalls when using stochastic processes to model macroevolution.

scholarly journals A variable-rate quantitative trait evolution model using penalized-likelihood

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11997
Author(s):  
Liam J. Revell
Keyword(s):  
Brownian Motion ◽  
Quantitative Trait ◽  
Penalized Likelihood ◽  
Comparative Methods ◽  
Character Trait ◽  
Likelihood Method ◽  
Rate Variation ◽  
Phylogenetic Comparative Methods ◽  
Trait Evolution ◽  
Rate Of Evolution

In recent years it has become increasingly popular to use phylogenetic comparative methods to investigate heterogeneity in the rate or process of quantitative trait evolution across the branches or clades of a phylogenetic tree. Here, I present a new method for modeling variability in the rate of evolution of a continuously-valued character trait on a reconstructed phylogeny. The underlying model of evolution is stochastic diffusion (Brownian motion), but in which the instantaneous diffusion rate (σ2) also evolves by Brownian motion on a logarithmic scale. Unfortunately, it’s not possible to simultaneously estimate the rates of evolution along each edge of the tree and the rate of evolution of σ2 itself using Maximum Likelihood. As such, I propose a penalized-likelihood method in which the penalty term is equal to the log-transformed probability density of the rates under a Brownian model, multiplied by a ‘smoothing’ coefficient, λ, selected by the user. λ determines the magnitude of penalty that’s applied to rate variation between edges. Lower values of λ penalize rate variation relatively little; whereas larger λ values result in minimal rate variation among edges of the tree in the fitted model, eventually converging on a single value of σ2 for all of the branches of the tree. In addition to presenting this model here, I have also implemented it as part of my phytools R package in the function multirateBM. Using different values of the penalty coefficient, λ, I fit the model to simulated data with: Brownian rate variation among edges (the model assumption); uncorrelated rate variation; rate changes that occur in discrete places on the tree; and no rate variation at all among the branches of the phylogeny. I then compare the estimated values of σ2 to their known true values. In addition, I use the method to analyze a simple empirical dataset of body mass evolution in mammals. Finally, I discuss the relationship between the method of this article and other models from the phylogenetic comparative methods and finance literature, as well as some applications and limitations of the approach.

scholarly journals The mating system affects the temperature sensitivity of male and female fertility

2021 ◽  
Author(s):  
Julian Baur ◽  
Dorian Jagusch ◽  
Piotr Michalak ◽  
Mareike Koppik ◽  
David Berger
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Mating System ◽  
Sex Difference ◽  
Climate Warming ◽  
Mating Systems ◽  
Female Fertility ◽  
Male And Female ◽  
Two Generations ◽  
Natural And Sexual Selection

1. To mitigate effects of climate change it is important to understand species responses to increasing temperatures. This has often been done by studying survival or activity at temperature extremes. Before such extremes are reached, however, effects on fertility may already be apparent. 2. Sex differences in the thermal sensitivity of fertility (TSF) could impact species persistence under climate warming because female fertility is typically more limiting to population growth than male fertility. However, little is known about sex differences in TSF. 3. Here we first demonstrate that the mating system can strongly influence TSF using the seed beetle Callosobruchus maculatus. We exposed populations carrying artificially induced mutations to two generations of short-term experimental evolution under alternative mating systems, manipulating the opportunity for natural and sexual selection on the mutations. We then measured TSF in males and females subjected to juvenile or adult heat stress. 4. Populations kept under natural and sexual selection had higher fitness, but similar TSF, compared to control populations kept under relaxed selection. However, females had higher TSF than males, and strikingly, this sex difference had increased over only two generations in populations evolving under sexual selection. 5. We hypothesized that an increase in male-induced harm to females during mating had played a central role in driving this evolved sex difference, and indeed, remating under conditions limiting male harassment of females reduced both male and female TSF. Moreover, we show that manipulation of mating system parameters in C. maculatus generates intraspecific variation in the sex difference in TSF equal to that found among a diverse set of studies on insects. 6. Our study provides a causal link between the mating system and TSF. Sexual conflict, (re)mating rates, and genetic responses to sexual selection differ among ecological settings, mating systems and species. Our study therefore also provides mechanistic understanding for the variability in previously reported TSFs which can inform future experimental assays and predictions of species responses to climate warming.

scholarly journals Is horizontal transmission really a problem for phylogenetic comparative methods? A simulation study using continuous cultural traits

2010 ◽  
Vol 365 (1559) ◽  
pp. 3903-3912 ◽  
Author(s):  
Thomas E. Currie ◽  
Simon J. Greenhill ◽  
Ruth Mace
Keyword(s):  
Cultural Evolution ◽  
Horizontal Transmission ◽  
Comparative Methods ◽  
Phylogenetic Comparative Methods ◽  
Ancestral State ◽  
Regression Analyses ◽  
Trait Evolution ◽  
Phylogenetic Methods ◽  
Cultural Traits ◽  
Future Work

Phylogenetic comparative methods (PCMs) provide a potentially powerful toolkit for testing hypotheses about cultural evolution. Here, we build on previous simulation work to assess the effect horizontal transmission between cultures has on the ability of both phylogenetic and non-phylogenetic methods to make inferences about trait evolution. We found that the mode of horizontal transmission of traits has important consequences for both methods. Where traits were horizontally transmitted separately , PCMs accurately reported when trait evolution was not correlated even at the highest levels of horizontal transmission. By contrast, linear regression analyses often incorrectly concluded that traits were correlated. Where simulated trait evolution was not correlated and traits were horizontally transmitted as a pair , both methods inferred increased levels of positive correlation with increasing horizontal transmission. Where simulated trait evolution was correlated, increasing rates of separate horizontal transmission led to decreasing levels of inferred correlation for both methods, but increasing rates of paired horizontal transmission did not. Furthermore, the PCM was also able to make accurate inferences about the ancestral state of traits. These results suggest that under certain conditions, PCMs can be robust to the effects of horizontal transmission. We discuss ways that future work can investigate the mode and tempo of horizontal transmission of cultural traits.

Measuring female aggregation in ungulate mating-system research: a red deer case study

2010 ◽  
Vol 37 (4) ◽  
pp. 301 ◽  
Author(s):  
Javier Pérez-González ◽  
Juan Carranza ◽  
Vicente Polo
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Mating Systems ◽  
Red Deer ◽  
Point Pattern ◽  
System Research ◽  
Distance Method ◽  
Spatial Methods ◽  
Ripley’S K ◽  
Ripley's K

Context. Mating systems are of central importance to the operation of sexual selection, with consequences for evolution and for the maintenance of genetic diversity. Female aggregation is one of the most important elements of mating systems because female distribution can influence the degree of polygyny. Measuring female aggregation requires finding the scale for the distribution pattern. Several spatial methods can be used to determine the scale of a point pattern; however, only one of them has been applied to mating-system research. Aims. Here, we assess three different spatial methods to determine the best one in finding the scale of female distribution for female-aggregation measures in a mating-system context. Methods. We describe and compare the spatial methods by applying them to 30 Iberian red deer (Cervus elaphus hispanicus) populations. We use spatial analyses for point patterns. Key results. Ripley’s K analysis was found to be the best method for determining the scale of female distribution and for quantifying female-aggregation parameters in our populations. Conclusions. Ripley’s K analysis, a distance method based on circles centred in individuals and that is widely used in ecological studies, allows the estimation of female aggregation and, hence, it can be used to measure sexual selection. Implications. This work describes the use of a distance method that can be applied to mating-system research (at least for ungulate populations) to obtain models with behavioural and evolutionary implications.

scholarly journals An atypical mating system in a neotropical manakin

2020 ◽  
Vol 7 (1) ◽  
pp. 191548 ◽  
Author(s):  
Milene G. Gaiotti ◽  
Michael S. Webster ◽  
Regina H. Macedo
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Mating Systems ◽  
Evolutionary Development ◽  
Selective Pressures ◽  
Exclusive Territories ◽  
Monogamous Species ◽  
Socially Monogamous ◽  
Mixed Paternity ◽  
Close Relatives

Most of the diversity in the mating systems of birds and other animals comes at higher taxonomic levels, such as across orders. Although divergent selective pressures should lead to animal mating systems that diverge sharply from those of close relatives, opportunities to examine the importance of such processes are scarce. We addressed this issue using the Araripe manakin ( Antilophia bokermanni ), a species endemic to a forest enclave surrounded by xeric shrublands in Brazil. Most manakins exhibit polygynous lekking mating systems that lack territoriality but exhibit strong sexual selection. In sharp contrast, we found that male Araripe manakins defended exclusive territories, and females nested within male territories. However, territoriality and offspring paternity were dissociated: males sired only 7% of nestlings from the nests within their territories and non-territorial males sired numerous nestlings. Moreover, female polyandry was widespread, with most broods exhibiting mixed paternity. Apparently, territories in this species function differently from both lekking arenas and resource-based territories of socially monogamous species. The unexpected territoriality of Araripe manakins and its dissociation from paternity is a unique evolutionary development within the manakin clade. Collectively, our findings underscore how divergences in mating systems might evolve based on selective pressures from novel environmental contexts.

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