scholarly journals Impact of male alternative reproductive tactics on female costs of sexual conflict under variation in operational sex ratio and population density

2017 ◽  
Vol 8 (1) ◽  
pp. 584-591 ◽  
Author(s):  
Erica Jeffery ◽  
Alex Córdoba‐Aguilar ◽  
Bernard Roitberg
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Sexual Conflict ◽  
Alternative Reproductive Tactics ◽  
Operational Sex Ratio ◽  
Reproductive Tactics

scholarly journals Investigating the interaction between inter-locus and intra-locus sexual conflict using hemiclonal analysis in Drosophila melanogaster

2021 ◽  
Author(s):  
Manas Geeta Arun ◽  
Tejinder Singh Chechi ◽  
Rakesh Meena ◽  
Shradha Dattaraya Bhosle ◽  
Srishti ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Ratio ◽  
Genetic Correlation ◽  
Empirical Evidence ◽  
Sexual Conflict ◽  
Genetic Basis ◽  
Operational Sex Ratio ◽  
Female Fitness ◽  
Male And Female ◽  
Males And Females

Divergence in the evolutionary interests of males and females leads to sexual conflict. Traditionally, sexual conflict has been classified into two types: inter-locus sexual conflict (IeSC) and intra-locus sexual conflict (IaSC). IeSC is modeled as a conflict over outcomes of intersexual reproductive interactions mediated by loci that are sex-limited in their effects. IaSC is thought to be a product of selection acting in opposite directions in males and females on traits with a common underlying genetic basis. While in their canonical formalisms IaSC and IeSC are mutually exclusive, there is growing support for the idea that the two may interact. Empirical evidence for such interactions, however, is limited. Here, we investigated the interaction between IeSC and IaSC in Drosophila melanogaster. Using hemiclonal analysis, we sampled 39 hemigenomes from a laboratory-adapted population of D. melanogaster. We measured the contribution of each hemigenome to adult male and female fitness at three different intensities of IeSC, obtained by varying the operational sex-ratio. Subsequently, we estimated the intensity of IaSC at each sex-ratio by calculating the intersexual genetic correlation for fitness and the proportion of sexually antagonistic fitness-variation. Our results indicate a statistically non-significant trend suggesting that increasing the strength of IeSC ameliorates IaSC in the population.

Reproductive behaviour of female rosy bitterling Rhodeus ocellatus in response to a female-biased operational sex ratio

Behaviour ◽  
2014 ◽  
Vol 151 (6) ◽  
pp. 755-768 ◽  
Author(s):  
Caiping Liao ◽  
Dan Yu ◽  
Yiyu Chen ◽  
Martin Reichard ◽  
Huanzhang Liu
Keyword(s):  
Sex Ratio ◽  
Active Role ◽  
Reproductive Behaviour ◽  
Operational Sex Ratio ◽  
Reproductive Tactics ◽  
Female Ratio ◽  
Dominant Female ◽  
Male Female Ratio ◽  
Shaped Pattern ◽  
Rhodeus Ocellatus

While the effect of Operational Sex Ratio (OSR) on reproductive behaviour of males has been studied extensively, little is known of the response of females facing a female-biased OSR. We investigated the effect of different OSRs on female reproductive behaviour using the rosy bitterling, Rhodeus ocellatus, a freshwater fish that lays its eggs inside the gills of living freshwater mussels. Three levels of OSR (male/female ratio 1:1, 1:3 and 1:5) were tested. We demonstrated that inspection of the mussel (spawning substrate) by individual females increased with increasingly female-biased OSR, but that the rate of following territorial male decreased. Aggression towards other females was not affected by the OSR. Interestingly, when a male bitterling led a non-dominant female towards the mussel, the dominant female would become aggressive to the male and chase the non-dominant female away. Aggression towards male followed a bell-shaped pattern and was highest at an OSR of 1:3. In both the female-biased OSRs examined, almost 50% of dominant females tended to chase away other females and defend the mussel, showing territoriality in a similar manner to males. These observations suggest that female reproductive behaviour is strongly affected by the OSR, and their reproductive tactics during courtship change from a passive role in courtship (following a male) to an active role in courtship (approaching a male), with presence of female territorial behaviour as the OSR becomes increasingly female-biased. This study provides strong evidence that a female-biased OSR has an important effect on female reproductive behaviour.

scholarly journals Adaptations to sexual selection and sexual conflict: insights from experimental evolution and artificial selection

2010 ◽  
Vol 365 (1552) ◽  
pp. 2541-2548 ◽  
Author(s):  
Dominic A. Edward ◽  
Claudia Fricke ◽  
Tracey Chapman
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Sexual Conflict ◽  
Artificial Selection ◽  
Experimental Evolution ◽  
Genetic Basis ◽  
Mating Behaviour ◽  
Evolutionary Change ◽  
Operational Sex Ratio ◽  
Adult Sex Ratio

Artificial selection and experimental evolution document natural selection under controlled conditions. Collectively, these techniques are continuing to provide fresh and important insights into the genetic basis of evolutionary change, and are now being employed to investigate mating behaviour. Here, we focus on how selection techniques can reveal the genetic basis of post-mating adaptations to sexual selection and sexual conflict. Alteration of the operational sex ratio of adult Drosophila over just a few tens of generations can lead to altered ejaculate allocation patterns and the evolution of resistance in females to the costly effects of elevated mating rates. We provide new data to show how male responses to the presence of rivals can evolve. For several traits, the way in which males responded to rivals was opposite in lines selected for male-biased, as opposed to female-biased, adult sex ratio. This shows that the manipulation of the relative intensity of intra- and inter-sexual selection can lead to replicable and repeatable effects on mating systems, and reveals the potential for significant contemporary evolutionary change. Such studies, with important safeguards, have potential utility for understanding sexual selection and sexual conflict across many taxa. We discuss how artificial selection studies combined with genomics will continue to deepen our knowledge of the evolutionary principles first laid down by Darwin 150 years ago.

scholarly journals Operational sex ratio, sexual conflict and the intensity of sexual selection

2008 ◽  
Vol 11 (5) ◽  
pp. 432-439 ◽  
Author(s):  
Patrick S. Fitze ◽  
Jean-François Le Galliard
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Sexual Conflict ◽  
Operational Sex Ratio

scholarly journals Intralocus sexual conflict can maintain alternative reproductive tactics

2021 ◽  
Author(s):  
Madilyn Marisa Gamble ◽  
Ryan G Calsbeek
Keyword(s):  
Sexual Conflict ◽  
Genetic Correlations ◽  
Alternative Reproductive Tactics ◽  
Specific Gene ◽  
Reproductive Tactics ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Intralocus Sexual Conflict ◽  
Maintenance Of Sex ◽  
Negative Frequency Dependent Selection

Alternative reproductive tactics (ARTs) are ubiquitous throughout the animal kingdom and widely regarded as an outcome of high variance in reproductive success. Proximate mechanisms underlying ARTs include genetically based polymorphisms, environmentally induced polymorphisms, and those mediated by a combination of genetic and environmental factors. However, few ultimate mechanisms have been proposed to explain the maintenance of ARTs over time, the most important of which have been disruptive and negative frequency-dependent selection. Here we explore the role that intralocus sexual conflict may play in the maintenance of sex-specific ARTs. We use a genetically explicit individual-based model in which body size influences both female fecundity and male tactic through a shared genetic architecture. By modeling ART maintenance under varying selection regimes and levels of sex-specific gene expression, we explore the conditions under which intralocus sexual conflict can maintain a hypothetical ART defined by larger (alpha) and smaller (beta) tactics. Our models consistently revealed that sexual conflict can result in the persistence of a sex-specific polymorphism over hundreds of generations, even in the absence of negative frequency-dependent selection. ARTs were maintained through correlated selection when one male ART has lower fitness but produces daughters with higher fitness. These results highlight the importance of understanding selection on both sexes when attempting to explain the maintenance of ARTs. Our results are consistent with a growing literature documenting genetic correlations between male ARTs and female fitness, suggesting that the maintenance of sex-specific ARTs through intralocus sexual conflict may be common and widespread in nature.

scholarly journals Kin-mediated plasticity in alternative reproductive tactics

2021 ◽  
Vol 288 (1956) ◽  
pp. 20211069
Author(s):  
Samuel J. Lymbery ◽  
Joseph L. Tomkins ◽  
Bruno A. Buzatto ◽  
David J. Hosken
Keyword(s):  
Population Density ◽  
Alternative Reproductive Tactics ◽  
Relative Fitness ◽  
Conditional Strategy ◽  
Reproductive Tactics ◽  
Full Sibling ◽  
Strategy Model ◽  
Body Weights ◽  
Indirect Fitness ◽  
Kin Structure

Conditional strategies occur when the relative fitness pay-off from expressing a given phenotype is contingent upon environmental circumstances. This conditional strategy model underlies cases of alternative reproductive tactics, in which individuals of one sex employ different means to obtain reproduction. How kin structure affects the expression of alternative reproductive tactics remains unexplored. We address this using the mite Rhizoglyphus echinopus , in which large males develop into aggressive ‘fighters’ and small males develop into non-aggressive ‘scramblers.’ Because only fighters kill their rivals, they should incur a greater indirect fitness cost when competing with their relatives, and thus fighter expression could be reduced in the presence of relatives. We raised mites in full-sibling or mixed-sibship groups and found that fighters were more common at higher body weights in full-sibling groups, not less common as we predicted (small individuals were almost exclusively scramblers in both treatments). This result could be explained if relatedness and cue variability are interpreted signals of population density, since fighters are more common at low densities in this species. Alternatively, our results may indicate that males compete more intensely with relatives in this species. We provide the first evidence of kin-mediated plasticity in the expression of alternative reproductive tactics.

scholarly journals Natural variation in social conditions affects male mate choosiness in the amphipod Gammarus roeselii

2021 ◽  
Author(s):  
Konrad Lipkowski ◽  
Sophie Steigerwald ◽  
Lisa M Schulte ◽  
Carolin Sommer-Trembo ◽  
Jonas Jourdan
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Natural Variation ◽  
Natural Populations ◽  
Social Background ◽  
Social Conditions ◽  
Background Information ◽  
Male Mating ◽  
Natural Environments ◽  
Male Mate

Abstract The extent of male mate choosiness is driven by a trade-off between various environmental factors associated with the costs of mate acquisition, quality assessment and opportunity costs. Our knowledge about natural variation in male mate choosiness across different populations of the same species, however, remains limited. In this study, we compared male mate choosiness across 10 natural populations of the freshwater amphipod Gammarus roeselii (Gervais 1835), a species with overall high male mating investments, and evaluated the relative influence of population density and sex ratio (both affecting mate availability) on male mate choosiness. We investigated amplexus establishment after separating mating pairs and presenting focal males with a novel, size-matched female from the same population. Our analysis revealed considerable effects of sex ratio and (to a lesser extent) population density on time until amplexus establishment (choosiness). Male amphipods are able to perceive variable social conditions (e.g., sex ratio) and modify their mating strategy accordingly: We found choosiness to be reduced in increasingly male-biased populations, whereas selectivity increases when sex ratio becomes female biased. With this, our study expands our limited knowledge on natural variations in male mate choosiness and illustrates the importance of sex ratio (i.e., level of competition) for male mating decisions in natural environments. Accounting for variation in sex ratios, therefore, allows envisioning a distinctive variation of choosiness in natural populations and highlights the importance of considering social background information in future behavioral studies.

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