scholarly journals Extremely rapid development and early reproduction reduces sexual selection in D. melanogaster populations.

2021 ◽  
Author(s):  
Avani Mital ◽  
Manaswini Sarangi ◽  
Bodhisatta Nandy ◽  
Neha Pandey ◽  
Amitabh Joshi
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Rapid Development ◽  
Fertilization Success ◽  
Direct Selection ◽  
Reproductive Competition ◽  
Short Development Time ◽  
Low Levels ◽  
Selection For

The role of sexual selection in mediating levels of sexual conflict has been demonstrated in a number of experimental evolution studies on Drosophila sp. where the level of competition among males for fertilization success was under direct selection. Here we report that selection for a short development time and early age at reproduction can lead to inadvertent changes in levels of sexual selection in D. melanogaster populations, affecting reproductive competition experienced by males. We demonstrate that faster developing and early reproducing populations showed very low levels of mating in their lifetime (likely being monogamous), low courtship levels, shorter copulation duration and longer maturation time, compared to their ancestral controls. We discuss these results in light of the previously demonstrated reduction of sexual conflict in these populations.

scholarly journals Reproductive Mode and Conflict Shape the Evolution of Male Attributes and Rate of Speciation in the Fish Family Poeciliidae

2021 ◽  
Vol 9 ◽  
Author(s):  
David N. Reznick ◽  
Joseph Travis ◽  
Bart J. A. Pollux ◽  
Andrew I. Furness
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Reproductive Mode ◽  
Fish Family ◽  
Cascading Effects ◽  
The Family ◽  
Maternal Provisioning ◽  
Functional Equivalent ◽  
Selection For

Sexual conflict is caused by differences between the sexes in how fitness is maximized. These differences are shaped by the discrepancy in the investment in gametes, how mates are chosen and how embryos and young are provided for. Fish in the family Poeciliidae vary from completely provisioning eggs before they are fertilized to providing virtually all resources after fertilization via the functional equivalent of a mammalian placenta. This shift in when females provision their young relative to when an egg is fertilized is predicted to cause a fundamental change in when and how sexual conflict is manifested. If eggs are provisioned before fertilization, there should be strong selection for females to choose with whom they mate. Maternal provisioning after fertilization should promote a shift to post-copulatory mate choice. The evolution of maternal provisioning may in turn have cascading effects on the evolution of diverse features of the biology of these fish because of this shift in when mates are chosen. Here we summarize what these consequences are and show that the evolution of maternal provisioning is indeed associated with and appears to govern the evolution of male traits associated with sexual selection. The evolution of placentas and associated conflict does not cause accelerated speciation, contrary to predictions. Accelerated speciation rate is instead correlated with the evolution of male traits associated with sexual selection, which implies a more prominent role of pre-copulatory reproductive isolation in causing speciation in this family.

scholarly journals Losses of female song with changes from tropical to temperate breeding in the New World blackbirds

2009 ◽  
Vol 276 (1664) ◽  
pp. 1971-1980 ◽  
Author(s):  
J. Jordan Price ◽  
Scott M. Lanyon ◽  
Kevin E. Omland
Keyword(s):  
Sexual Selection ◽  
New World ◽  
Female Song ◽  
Complex Song ◽  
Evolutionary Changes ◽  
Apparent Relationship ◽  
Song Production ◽  
Selection For ◽  
The Tropics

Birds in which both sexes produce complex songs are thought to be more common in the tropics than in temperate areas, where typically only males sing. Yet the role of phylogeny in this apparent relationship between female song and latitude has never been examined. Here, we reconstruct evolutionary changes in female song and breeding latitude in the New World blackbirds (Icteridae), a family with both temperate and tropical representatives. We provide strong evidence that members of this group have moved repeatedly from tropical to temperate breeding ranges and, furthermore, that these range shifts were associated with losses of female song more often than expected by chance. This historical perspective suggests that male-biased song production in many temperate species is the result not of sexual selection for complex song in males but of selection against such songs in females. Our results provide new insights into the differences we see today between tropical and temperate songbirds, and suggest that the role of sexual selection in the evolution of bird song might not be as simple as we think.

Influence of density and major histocompatibility genotype on sexual selection in a salmonid alternative mating strategy

2012 ◽  
Vol 69 (4) ◽  
pp. 670-680 ◽  
Author(s):  
Laura K. Weir ◽  
Jeffrey A. Hutchings ◽  
Daniel D. Heath
Keyword(s):  
Sexual Selection ◽  
Salmo Salar ◽  
Fertilization Success ◽  
Mating Strategy ◽  
Male Mating ◽  
Salmonid Fishes ◽  
Major Histocompatibility ◽  
Main Determinant ◽  
Alternative Mating Strategy

Various mechanisms of sexual selection can occur at both the whole organism and gamete levels. Fertilization success in salmonid fishes is largely determined by behavioural competition within and between “fighter” and “sneaker” male strategies, but is also influenced by interactions among gametes. We investigated the influence of density, fighter male presence, and major histocompatibility (MH) genotype on patterns of fertilization success in sneaker Atlantic salmon ( Salmo salar ). At low density and in the absence of fighter males, monopolization by single sneaker males occurred, suggesting that male–male competition was the main determinant of fertilization success. By contrast, at high density and (or) in the presence of fighter males, several sneakers succeeded in fertilizing eggs. Our study, the first to investigate the role of MH-mediated fertilization for a genetically based alternative male mating strategy, suggests that a larger proportion of eggs were fertilized by sneakers whose MH genotypes were more similar to those of the female than expected by chance. These findings highlight the importance of examining sexual selection under different competitive conditions.

scholarly journals Sexual size dimorphism and sexual selection in artiodactyls

2020 ◽  
Vol 31 (3) ◽  
pp. 792-797
Author(s):  
Marcelo H Cassini
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Group Size ◽  
Sexual Size Dimorphism ◽  
Alternative Hypothesis ◽  
Mammalian Species ◽  
Generalized Least Squares ◽  
Size Dimorphism ◽  
Selection For

Abstract Sexual size dimorphism is biased toward males in most mammalian species. The most common explanation is precopulatory intramale sexual selection. Large males win fights and mate more frequently. In artiodactyls, previous tests of this hypothesis consisted of interspecific correlations of sexual dimorphism with group size as a surrogate for the intensity of sexual selection (Is). However, group size is not a proper measure of sexual selection for several reasons as is largely recognized in other mammalian taxa. I conducted an interspecific test on the role of sexual selection in the evolution of sexual dimorphism using the variance in genetic paternity as a proxy for the Is. I reviewed the literature and found 17 studies that allowed estimating Is= V/(W2), where V and W are the variance and mean number of offspring per male, respectively. A phylogenetic generalized least squares analysis indicated that dimorphism (Wm/Wf) showed a significant positive regression with the intensity of sexual selection but not group size (multiple r2= 0.40; F3,17= 12.78, P = 0.002). This result suggests that sexual selection may have played a role in the evolution of sexual size dimorphism in Artiodactyla. An alternative hypothesis based on natural selection is discussed.

scholarly journals Animal personalities and their implications for complex signaling

2014 ◽  
Vol 60 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Nicholas Dirienzo ◽  
Ann V Hedrick
Keyword(s):  
Sexual Selection ◽  
Behavioral Ecology ◽  
Ecological Processes ◽  
Signaling Systems ◽  
Signaling Complex ◽  
Selection For ◽  
Complex Signaling ◽  
Animal Personalities ◽  
Signaling Interactions

Abstract Animal personalities have been a major focus of behavioral ecology over the past decade. Consistent individual differences in behavior have been found across taxa, and have been shown to influence a range of ecological processes. The role of personalities in sexual selection has been considered, and examples exist that show selection for personality traits with both assortative and disassortative mating patterns between personality types. One overlooked aspect of the personality and sexual selection literature is the potential for personality-signaling interactions, specifically with complex signaling. Complex signaling is a diverse topic in itself, and in short, consists of multiple signals within one or more modalities that interact to elicit a receiver response. Research into complex signaling has been thorough, although at times studies discover complex signaling systems that fail to fit into one of the existing hypotheses in the literature. Here, we argue that personalities may interact with complex signaling, which should be considered by researchers of both personality and sexual selection and communication. We describe several ways in which personality-complex signaling interactions could affect both the signaler and receiver, and the way in which they may drive personality-specific signals as well as receiver preferences. Finally, we discuss how considering personality in complex signaling studies may inform theory as well as improve the ability of researchers to accurately describe its function.

scholarly journals Conspecific sperm precedence is reinforced but sexual selection weakened in sympatric populations ofDrosophila

2016 ◽  
Author(s):  
Dean M. Castillo ◽  
Leonie C. Moyle
Keyword(s):  
Sexual Selection ◽  
Reproductive Isolation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Genetic Basis ◽  
Direct Selection ◽  
Sperm Precedence ◽  
Sympatric Populations ◽  
Selection For ◽  
The Cost

SUMMARYSexual selection is well recognized as a driver of reproductive isolation between lineages. However, selection for increased reproductive isolation could reciprocally change the outcomes of sexual selection, when these processes share a genetic basis. Direct selection for reproductive isolation occurs in the context of ‘reinforcement’, where selection acts to increase prezygotic barriers to reduce the cost of heterospecific matings. Many studies of reinforcement focus on premating reproductive barriers, however postmating traits-such as conspecific sperm precedence (CSP)-can also respond to reinforcing selection. We tested whether i) CSP responded to reinforcing selection, and ii) this response in sympatric populations altered intraspecific sperm competition (ISC) and the strength of sexual selection, with the sister speciesDrosophila pseudoobscuraandD. persimilis. We used sperm competition experiments to evaluate differences in CSP and ISC between two sympatric and two allopatric populations ofD. pseudoobscura. Using multiple genotypes for each population allowed us to estimate not only patterns of phenotype divergence, but also the opportunity for sexual selection within each population. Consistent with a pattern of reinforcement, the sympatric populations had higher mean CSP. Moreover, ISC was altered in sympatric populations, where we observed decreased average offensive sperm competitive ability against conspecific males, allowing less opportunity for sexual selection to operate within these populations. These data demonstrate that strong reinforcing selection for reproductive isolation can have consequences for sexual selection and sexual interactions within species, in these important postmating sperm competition traits.

scholarly journals An Alternative Paradigm for the Role of Antimalarial Plants in Africa

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Steven Maranz
Keyword(s):  
High Probability ◽  
Antimalarial Activity ◽  
Direct Selection ◽  
Selection For ◽  
African Plants ◽  
Parasite Populations ◽  
Major Emphasis

Most investigations into the antimalarial activity of African plants are centered on finding an indigenous equivalent to artemisinin, the compound from which current frontline antimalarial drugs are synthesized. As a consequence, the standard practice in ethnopharmacological research is to usein vitroassays to identify compounds that inhibit parasites at nanomolar concentrations. This approach fails to take into consideration the high probability of acquisition of resistance to parasiticidal compounds since parasite populations are placed under direct selection for genetic that confers a survival advantage. Bearing in mind Africa's long exposure to malaria and extensive ethnobotanical experimentation with both therapies and diet, it is more likely that compounds not readily overcome byPlasmodiumparasites would have been retained in the pharmacopeia and cuisine. Such compounds are characterized by acting primarily on the host rather than directly targeting the parasite and thus cannot be adequately exploredin vitro. If Africa's long history with malaria has in fact produced effective plant therapies, their scientific elucidation will require a major emphasis onin vivoinvestigation.

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