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.

Effects of alternative male mating strategies on characteristics of sperm production in the Atlantic salmon ( Salmo salar ): theoretical and empirical investigations

1995 ◽  
Vol 350 (1334) ◽  
pp. 391-399 ◽  
Keyword(s):  
Atlantic Salmon ◽  
Sperm Competition ◽  
Salmo Salar ◽  
Reproductive Traits ◽  
Fertilization Success ◽  
Mating Strategies ◽  
Male Mating ◽  
Sperm Length ◽  
Male Mating Strategies ◽  
Natural Variance

Atlantic salmon ( Salmo salar ) males mature as either tiny precocious parr before seaward migration, or as older and larger anadromous males. Anadromous males dominate the spawning redds and aggressively defend females against parr intrusions. Parr gain fertilizations by sneaking in to ejaculate while anadromous males and females spawn. Such differences in mating advantage generate asymmetries in risk of sperm competition between the male strategies. Theoretical sperm competition models predict that males typically mating in disfavoured roles (here, the parr strategy) should be selected to offset this disadvantage by investing more into spermatogenesis to achieve fertilization success. First, we present a theoretical model which analyses gametic expenditure for salmon parr and anadromous male reproductive strategies. We then use the natural variance in mating pattern within this species to compare empirically how males invest in spermatogenesis. A range of reproductive traits were measured for both male strategies. Absolutely, anadromous males have larger testes and produce greater numbers of sperm than parr males. However, results show that parr invest relatively more heavily into total spermatogenesis, and have a larger gonosomatic index than anadromous males. Relative to body size, parr produced greater numbers of sperm and volumes of stripped ejaculate. There was no difference in sperm length between the two male strategies. However, more sperm were motile in parr ejaculates, and these sperm lived longer than anadromous male sperm. Our findings may explain how male parr, under elevated risks of sperm competition and occupying a disfavoured mating role (parr weigh only 0.15% of the average body mass of anadromous males) achieve disproportionately high fertilization success.

scholarly journals Polyandry as a mediator of sexual selection before and after mating

2013 ◽  
Vol 368 (1613) ◽  
pp. 20120042 ◽  
Author(s):  
Charlotta Kvarnemo ◽  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Mating Success ◽  
Multiple Mating ◽  
Reproductive Rate ◽  
Male Mating ◽  
Before And After ◽  
Main Driver ◽  
Future Work ◽  
Potential Reproductive Rate

The Darwin–Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution.

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 Cognitive ability is heritable and predicts the success of an alternative mating tactic

2015 ◽  
Vol 282 (1809) ◽  
pp. 20151046 ◽  
Author(s):  
Carl Smith ◽  
André Philips ◽  
Martin Reichard
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Learning Task ◽  
Paternity Analysis ◽  
Male Mating ◽  
Paternal Effects ◽  
Design Learning ◽  
Alternative Mating Tactic ◽  
Cognitive Traits

The ability to attract mates, acquire resources for reproduction, and successfully outcompete rivals for fertilizations may make demands on cognitive traits—the mechanisms by which an animal acquires, processes, stores and acts upon information from its environment. Consequently, cognitive traits potentially undergo sexual selection in some mating systems. We investigated the role of cognitive traits on the reproductive performance of male rose bitterling ( Rhodeus ocellatus ), a freshwater fish with a complex mating system and alternative mating tactics. We quantified the learning accuracy of males and females in a spatial learning task and scored them for learning accuracy. Males were subsequently allowed to play the roles of a guarder and a sneaker in competitive mating trials, with reproductive success measured using paternity analysis. We detected a significant interaction between male mating role and learning accuracy on reproductive success, with the best-performing males in maze trials showing greater reproductive success in a sneaker role than as a guarder. Using a cross-classified breeding design, learning accuracy was demonstrated to be heritable, with significant additive maternal and paternal effects. Our results imply that male cognitive traits may undergo intra-sexual selection.

scholarly journals Epicuticular Compounds of Protopiophila litigata (Diptera: Piophilidae): Identification and Sexual Selection Across Two Years in the Wild

2019 ◽  
Vol 113 (1) ◽  
pp. 40-49
Author(s):  
Christopher S Angell ◽  
Sharon Curtis ◽  
Anaïs Ryckenbusch ◽  
Howard D Rundle
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Mating Success ◽  
Natural Populations ◽  
Male Mating ◽  
Cross Sectional ◽  
Or Groups ◽  
In The Wild ◽  
Males And Females

Abstract The epicuticular compounds (ECs) of insects serve both to waterproof the cuticle and, in many taxa, as pheromones that are important for various social interactions, including mate choice within populations. However, ECs have not been individually identified in many species and most studies of their role in mate choice have been performed in a laboratory setting. Here we newly identify and quantify the ECs of the antler fly, Protopiophila litigata Bonduriansky, and use a cross-sectional selection analysis to quantify their association with male mating success in the wild across two years (2013 and 2017). The ECs of antler flies include straight-chain and methylated alkanes, alkenes, and a family of branched wax esters. We find all ECs to be shared between males and females but also demonstrate sexual dimorphism in the abundance of several. Male EC relative abundances were significantly associated with mating success in both years, although the multivariate direction of selection differed significantly between the years. Surprisingly, only two of the 18 compounds (or groups of compounds) we identified were similarly associated with mating success across the sampling years. In 2017, we further partitioned sexual selection into intra- and intersexual components, revealing selection on ECs to be significant via female choice but not male–male competition. Our study is one of few to investigate the potential role of ECs in mating success in the wild and adds to a growing body of evidence demonstrating significant temporal variability in selection in natural populations.

scholarly journals Epicuticular compounds of Protopiophila litigata (Diptera: Piophilidae): identification and sexual selection across two years in the wild

2020 ◽  
Author(s):  
Christopher Angell ◽  
Sharon Curtis ◽  
Anaïs Ryckenbusch ◽  
Howard Rundle
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Mating Success ◽  
Natural Populations ◽  
Male Mating ◽  
Cross Sectional ◽  
Or Groups ◽  
In The Wild ◽  
Males And Females

The epicuticular compounds (ECs) of insects serve both to waterproof the cuticle and, in many taxa, as pheromones that are important for various social interactions including mate choice within populations. However, ECs have not been individually identified in many species and most studies of their role in mate choice have been performed in a laboratory setting. Here we newly identify and quantify the ECs of the antler fly, Protopiophila litigata Bonduriansky, and use a cross-sectional selection analysis to quantify their association with male mating success in the wild across two years (2013 and 2017). The ECs of antler flies include straight-chain and methylated alkanes, alkenes, and a family of branched wax esters. We find all ECs to be shared between males and females but also demonstrate sexual dimorphism in the abundance of several. Male EC relative abundances were significantly associated with mating success in both years, although the multivariate direction of selection differed significantly between the years. Surprisingly, only two of the 18 compounds (or groups of compounds) we identified were similarly associated with mating success across the sampling years. In 2017, we further partitioned sexual selection into intra- and intersexual components, revealing selection on ECs to be significant via female choice but not male-male competition. Our study is one of few to investigate the potential role of ECs in mating success in the wild and adds to a growing body of evidence demonstrating significant temporal variability in selection in natural populations.

The effect of porcine somatotropin on growth, and survival in seawater of Atlantic salmon (Salmo salar) parr

1976 ◽  
Vol 54 (4) ◽  
pp. 531-535 ◽  
Author(s):  
M. P. Komourdjian ◽  
R. L. Saunders ◽  
J. C. Fenwick
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Hormone Treatment ◽  
Hormone Treatment ◽  
Control Fish ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Porcine Somatotropin

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.

Fertilization dynamics of sperm from different male mating tactics in bluegill (Lepomis macrochirus)

2005 ◽  
Vol 83 (12) ◽  
pp. 1638-1642 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
Gary Burness
Keyword(s):  
Sperm Competition ◽  
Lepomis Macrochirus ◽  
Fertilization Success ◽  
Male Mating ◽  
Motile Sperm ◽  
Mating Tactics ◽  
Sperm Activation ◽  
Competition Theory ◽  
Sperm Density ◽  
Over Time

Sperm competition results in the evolution of ejaculate characteristics such as high sperm density, high motility, and fast sperm swimming speed. A fundamental assumption of sperm competition theory is that ejaculates with high motility and fast-swimming sperm have an advantage with respect to fertilization success. We tested this assumption by studying the fertilization dynamics of alternative mating tactics (cuckolders and parentals) of male bluegill (Lepomis macrochirus Rafinesque, 1819). Sneakers (cuckolders) have faster swimming sperm and a higher proportion of motile sperm immediately following sperm activation than do parentals; however, these variables decline more quickly over time in sneaker sperm than in the sperm of parental males. We used a controlled fertilization experiment to test the prediction that parental males will have higher fertilization success than sneakers late in the sperm activation cycle because of the reduced rate of decline in ejaculate quality over time. We found that as the time from sperm activation increases parental sperm fertilizes more eggs than the sperm of sneakers. Our results support the idea that fertilization success is higher when ejaculates contain a higher proportion of either motile sperm or faster swimming sperm, all else being equal. In addition, after controlling for time from sperm activation, we found a significant bias in fertilization success toward parental males, suggesting that cryptic female choice might play a role in fertilization dynamics.

Sign in / Sign up

Export Citation Format

Share Document