Patterns of Gonadic Development and Operational Sex Ratio Promote Promiscuity of Euxesta bilimeki (Diptera:Ulidiidae)

2020 ◽  
Author(s):  
Christian L Rodríguez-Enríquez ◽  
Diana Pérez-Staples ◽  
Oscar Rios-Cardenas ◽  
Juan Rull
Keyword(s):  
Sex Ratio ◽  
Protein Content ◽  
Operational Sex Ratio ◽  
Mating Frequency ◽  
Body Protein ◽  
Protein Ingestion ◽  
Full Complement ◽  
Individual Mating ◽  
Males And Females ◽  
Testes Size

Abstract Promiscuous mating systems are widely distributed among animals and can be promoted by operational sex ratios (number of receptive adults; OSR). In populations where OSR is not biased towards any sex, the possibility that males and females mate with several individuals increases. For both sexes to synchronize in time and space for reproduction, adults should possess or simultaneously acquire nutrients required to reach sexual maturity. Among synovigenic (without a full complement of eggs at eclosion) species, nutrient acquisition, protein in particular, may influence the OSR. In the Agave fly Euxesta bilimeki (Hendel) (Diptera: Ulidiidae), both sexes engage in multiple mating and females frequently expel all or part of the ejaculate. Here, we assessed the effect of protein intake on gonadic development, and estimated OSR from field-collected individuals. Body protein content was compared between wild and laboratory individuals with access to different diets, and mating frequency and individual mating rate were analyzed for cohorts at a 1:1 sex ratio. Both sexes required protein ingestion for gonadic development, but there were no differences in protein content between field-collected males and males fed protein and sugar in the laboratory, despite the fact that males assigned 9.3% of their corporal weight to testicles. Euxesta bilimeki is a promiscuous species where both males and females mate multiply with one or several individuals in short periods of time; thus, large testes size may be linked to the need of voluminous ejaculate production, and might be further exacerbated by female ejaculate expulsion.

Short term changes in sex ratio and density alter coercive male mating tactics

Behaviour ◽  
2010 ◽  
Vol 147 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
James Cureton II ◽  
Raelynn Deaton ◽  
Rachel Martin
Keyword(s):  
Sex Ratio ◽  
Reproductive Activity ◽  
Operational Sex Ratio ◽  
Mating Frequency ◽  
Male Mating ◽  
Mating Tactics ◽  
Short Term ◽  
Classic Theory ◽  
Males And Females ◽  
The Impact

AbstractShort term fluctuations in operational sex ratio (OSR) and density can strongly influence male mating, often exacerbating conflict between males and females. Livebearing fishes of the genus Gambusia are ideal for investigating sexual conflict because males of all sizes mate coercively. In this study, we tested how short-term fluctuations in OSR and density influence coercive male mating behaviours. Specifically, we tested the prediction that as OSR becomes more female biased, males will mate with all available females. In contrast, as OSR becomes more male biased, male aggression will inhibit mating frequency. As predicted, males mated with more females as the number of available females increased. Moreover, males were less aggressive as the proportion of females increased and more aggressive as the number of males increased. This resulted in an inverse relationship between mating and aggression with OSR and density. Coercive males attempt to maximize their reproductive success by mating with all available females, which supports classic theory on the impact of OSR and density on reproductive activity.

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.

Sociosexuality and sex ratio: Sex differences and local markets

2005 ◽  
Vol 28 (2) ◽  
pp. 288-288
Author(s):  
John Lazarus
Keyword(s):  
Sex Differences ◽  
Sex Ratio ◽  
Local Level ◽  
Psychological Effects ◽  
Operational Sex Ratio ◽  
Know How ◽  
Males And Females ◽  
Mating Market ◽  
The Relationship ◽  
Ratio Measure

Operational sex ratio (OSR) is the correct sex ratio measure for predicting sociosexuality, but it is unclear whether this is the measure used. It would be valuable to know how OSR and sociosexuality correlate separately for males and females. The relationship between sociosexuality and OSR should also be examined with OSR measured at the local level of the mating market, where sex ratio must be having its psychological effects.

Modeling Mating Patterns Given Mutual Mate Choice: The Importance of Individual Mating Preferences and Mating System

2003 ◽  
Vol 11 (03) ◽  
pp. 205-219 ◽  
Author(s):  
Carmen Bessa-Gomes ◽  
Jean Clobert ◽  
Stéphane Legendre ◽  
Anders Pape Møller
Keyword(s):  
Mate Choice ◽  
Sex Ratio ◽  
Mating System ◽  
Population Biology ◽  
Structured Populations ◽  
Operational Sex Ratio ◽  
Mating Preferences ◽  
Mating Patterns ◽  
Single Sex ◽  
Individual Mating

When we consider structured populations with sexual reproduction, the distribution of characters among mating pairs may influence the population biology, namely its dynamics and genetics. In the present paper, we propose a general framework to estimate the population mating patterns taking into account individual mating preferences and mating system, thus taking into account the inter- and intra-sexual interactions such as mate competition and mate choice. According to our results, mating patterns are not a direct reflection of mating preferences, but also depend upon the average sex ratio between individuals that are ready to mate at any given time (i.e., the Operational Sex Ratio, OSR). Therefore, mating patterns should be assessed not only in function of preferences, but also of OSR. It is then possible to distinguish three OSR regions: (1) the equilibrium OSR, where there is a predominance of assortative mating patterns due to differential access to mates (inter-sexual interactions); (2) the slightly biased OSR, where there is a high diversity of mating patterns and no clear predominance of inter- or intra-sexual interactions; and (3) the highly biased OSR where there is a predominance of mating patterns corresponding to single-sex uniform preferences and an increased influence of intra-sexual interactions. We hope that this approach may allow to further explore the interaction between OSR and mate choice, namely how such interaction may affect sexual selection and mate choice tactics.

The influence of operational sex ratio on reproductive success in male sheepshead minnow (Cyprinodon variegatus)

Behaviour ◽  
2020 ◽  
Vol 158 (1) ◽  
pp. 19-34
Author(s):  
Timothy Paciorek ◽  
Michael McQuillan ◽  
Layla Al-Shaer ◽  
Andrew Bloch ◽  
Zachary Carroll ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Sex Ratio ◽  
Experimental Tests ◽  
Reproductive Behaviour ◽  
Operational Sex Ratio ◽  
Territory Size ◽  
Cyprinodon Variegatus ◽  
Aggressive Male ◽  
Males And Females ◽  
Spawning Sites

Abstract Operational sex ratio (OSR) is predicted to influence the direction and intensity of sexual selection. Thus, as the relative numbers of reproductively active males vs females change, the behavioural competition among males and their differences in reproductive success are also predicted to change. While these outcomes seem intuitively obvious, there have been few experimental tests that examine these predictions. Here, we experimentally tested the relationship between OSR and reproductive behaviour in sheepshead minnows (Cyprinodon variegatus) competing in laboratory-based pools. Males and females were assigned to one of three OSRs (female-biased, equal, or male-biased). We monitored aggression, territory size, and number of eggs acquired by the most aggressive male, termed the “focal male,” in the pool. We used microsatellite analyses to determine the parentage of the eggs within the focal males’ territories. Focal males, by definition, were the most aggressive individual in their pools, but the degree of their aggressiveness and number of spawning sites they controlled were not influenced by OSR. Compared to focal males in the equal and male-biased OSRs, focal males in the female-biased OSR did receive more eggs but the OSR did not appear to influence the percentage of eggs they fathered on their own spawning sites. We speculate that a focal male’s competitive ability is more important to reproductive success than the number of other males and females present.

The effect of sex ratio on size-assortative mating in two explosively breeding anurans

2015 ◽  
Vol 36 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Jiří Vojar ◽  
Petr Chajma ◽  
Oldřich Kopecký ◽  
Vladimír Puš ◽  
Miroslav Šálek
Keyword(s):  
Sex Ratio ◽  
Assortative Mating ◽  
Rana Temporaria ◽  
Bufo Bufo ◽  
The Body ◽  
Operational Sex Ratio ◽  
Wild Populations ◽  
Individual Fitness ◽  
Widespread Phenomenon ◽  
Males And Females

Size-assortative mating (SAM) is a widespread phenomenon related to individual fitness. In our study, we examined: (i) the appearance of SAM, and (ii) the effect of sex ratio on intensity of SAM in wild populations of two explosively breeding anurans, common frogs,Rana temporaria, and common toads,Bufo bufo. Despite a higher male-biased operational sex ratio (OSR) in toads, the body lengths of the paired males and females were significantly correlated only in frogs. Increasing male-male competition, assessed via the OSR, resulted in a stronger correlation also in frogs only. Thus, great variability in the presence and intensity of SAM has been observed within both studied species.

The effects of population density and sex ratio on mating frequency ofEarias insulana males and females in laboratory cultures

1983 ◽  
Vol 11 (3-4) ◽  
pp. 145-149 ◽  
Author(s):  
M. Klein ◽  
Shoshana Yathom ◽  
Sara Keren ◽  
Shlomit Levski ◽  
Susana Tal
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Mating Frequency ◽  
Laboratory Cultures ◽  
Males And Females

scholarly journals 224 A method for estimating the target for protein energy retention in sheep

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 143-143
Author(s):  
Holland C Dougherty ◽  
Hutton Oddy ◽  
Mark Evered ◽  
James W Oltjen
Keyword(s):  
Body Composition ◽  
Protein Content ◽  
Heat Production ◽  
Crude Protein ◽  
Muscle Protein ◽  
Energy Utilization ◽  
Body Protein ◽  
Protein Mass ◽  
Reference Weight ◽  
Animal Growth

Abstract Target protein mass at maturity is a common “attractor” used in animal models to derive components of animal growth. This target muscle protein at maturity, M*, is used as a driver of a model of animal growth and body composition with pools representing muscle and visceral protein; where viscera is heart, lungs, liver, kidneys, reticulorumen and gastrointestinal tract; and muscle is non-visceral protein. This M* term then drives changes in protein mass and heat production, based on literature data stating that heat production scales linearly with protein mass but not liveweight. This led us to adopt a modelling approach where energy utilization is directly related to protein content of the animal, and energy not lost as heat or deposited as protein is fat. To maintain continuity with existing feeding systems we estimate M* from Standard Reference Weight (SRW) as follows: M* (kJ) = SRW * SHRINK * (1-FMAT) * (MUSC) * (CPM)* 23800. Where SRW is standard reference weight (kg), SHRINK is the ratio of empty body to live weight (0.86), FMAT is proportion of fat in the empty body at maturity (0.30), MUSC is the proportion of empty body protein that is in muscle (0.85), CPM is the crude protein content of fat-free muscle at maturity (0.21), and 23800 is the energetic content (kJ) of a kilogram of crude protein. Values for SHRINK, FMAT, MUSC and CPM were derived from a synthesis of our own experimental data and the literature. For sheep, these values show M* to be: M* (kJ) = SRW * 0.86* (1-0.3) * 0.85 * 0.21 *23800 = SRW * 2557. This method allows for use of existing knowledge regarding standard reference weight and other parameters in estimating target muscle mass at maturity, as part of a model of body composition and performance in ruminants.

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