Determinants Of Male Mating Success Research Articles

Characteristics of breeding habitat, genetic mating system, and determinants of male mating success in the sponge-dwelling goby Elacatinus lori

Characteristics of breeding habitat, genetic mating system, and determinants of male mating success in the sponge-dwelling goby Elacatinus lori

Temporal and age-related variations in calling and mating patterns of the Indian population of spotted pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae)

Maruca vitrata is an important pantropical and polyphagous insect pest of grain legumes. The adult emergence pattern and temporal variations in the calling and mating behaviour of M. vitrata across ages were studied. Observations revealed that adult emergence was not influenced significantly by sex, but by the time of the day. Calling activity is a strong determinant of male mating success in insects. An age-dependent female calling pattern was observed. Females seldom called on their day of emergence, calling percentage was low to nil in the first four hours of scotophase but reached a peak in the fifth hour. The calling patterns of females of different ages were similar except that there were two peaks of calling for 3 and 4 days old females. Like calling, the mating pattern was also age-dependent, i.e. M. vitrata mating frequency was maximum at 3-days of age and thereafter decreased gradually with age. The highest mating frequency (30.83%) was observed at 2200 h for 3-day-old moths. The current study revealed that age dependant and distinct patterns in female calling, synchronous male responsiveness leading to mating in M. vitrata. The output of the study could be utilized in various aspects of M. vitrata semiochemical based research.

Male competition and the evolution of mating and life-history traits in experimental populations of Aedes aegypti.

Aedes aegypti is an important disease vector and a major target of reproductive control efforts. We manipulated the opportunity for sexual selection in populations of Ae. aegypti by controlling the number of males competing for a single female. Populations exposed to higher levels of male competition rapidly evolved higher male competitive mating success relative to populations evolved in the absence of competition, with an evolutionary response visible after only five generations. We also detected correlated evolution in other important mating and life-history traits, such as acoustic signalling, fecundity and body size. Our results indicate that there is ample segregating variation for determinants of male mating competitiveness in wild populations and that increased male mating success trades-off with other important life-history traits. The mating conditions imposed on laboratory-reared mosquitoes are likely a significant determinant of male mating success in populations destined for release.

Correlational selection on personality and social plasticity: morphology and social context determine behavioural effects on mating success.

Despite a central line of research aimed at quantifying relationships between mating success and sexually dimorphic traits (e.g., ornaments), individual variation in sexually selected traits often explains only a modest portion of the variation in mating success. Another line of research suggests that a significant portion of the variation in mating success observed in animal populations could be explained by correlational selection, where the fitness advantage of a given trait depends on other components of an individual's phenotype and/or its environment. We tested the hypothesis that interactions between multiple traits within an individual (phenotype dependence) or between an individual's phenotype and its social environment (context dependence) can select for individual differences in behaviour (i.e., personality) and social plasticity. To quantify the importance of phenotype- and context-dependent selection on mating success, we repeatedly measured the behaviour, social environment and mating success of about 300 male stream water striders, Aquarius remigis. Rather than explaining individual differences in long-term mating success, we instead quantified how the combination of a male's phenotype interacted with the immediate social context to explain variation in hour-by-hour mating decisions. We suggest that this analysis captures more of the mechanisms leading to differences in mating success. Males differed consistently in activity, aggressiveness and social plasticity. The mating advantage of these behavioural traits depended on male morphology and varied with the number of rival males in the pool, suggesting mechanisms selecting for consistent differences in behaviour and social plasticity. Accounting for phenotype and context dependence improved the amount of variation in male mating success we explained statistically by 30-274%. Our analysis of the determinants of male mating success provides important insights into the evolutionary forces that shape phenotypic variation. In particular, our results suggest that sexual selection is likely to favour individual differences in behaviour, social plasticity (i.e., individuals adjusting their behaviour), niche preference (i.e., individuals dispersing to particular social conditions) or social niche construction (i.e., individuals modifying the social environment). The true effect of sexual traits can only be understood in interaction with the individual's phenotype and environment.

Size, sounds and sex: interactions between body size and harmonic convergence signals determine mating success in Aedes aegypti.

BackgroundSeveral new mosquito control strategies will involve the release of laboratory reared males which will be required to compete with wild males for mates. Currently, the determinants of male mating success remain unclear. The presence of convergence between male and female harmonic flight tone frequencies during a mating attempt have been found to increase male mating success in the yellow fever mosquito, Aedes aegypti. Size has also been implicated as a factor in male mating success. Here, we investigated the relationships among body size, harmonic convergence signalling, and mating success. We predicted that harmonic convergence would be an important determinant of mating success and that large individuals would be more likely to converge.MethodsWe used diet to manipulate male and female body size and then measured acoustic interactions during mating attempts between pairs of different body sizes. Additionally, we used playback experiments to measure the direct effect of size on signalling performance.ResultsIn live pair interactions, harmonic convergence was found to be a significant predictor of copula formation. However, we also found interactions between harmonic convergence behaviour and body size. The probability that a given male successfully formed a copula was a consequence of his size, the size of the female encountered, and whether or not they converged. While convergence appears to be predictive of mating success regardless of size, the positive effect of convergence was modulated by size combinations. In playbacks, adult body size did not affect the probability of harmonic convergence responses.ConclusionsBoth body size and harmonic convergence signalling were found to be determinants of male mating success. Our results suggest that in addition to measuring convergence ability of mass release lines that the size distribution of released males may need to be adjusted to complement the size distribution of females. We also found that diet amount alone cannot be used to increase male mating success or convergence probability. A clearer understanding of convergence behaviours, their relationship to mating success, and factors influencing convergence ability would provide the groundwork for improving the mating performance of laboratory reared lines.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1914-6) contains supplementary material, which is available to authorized users.

Spatio-Temporal Dynamics of Field Cricket Calling Behaviour: Implications for Female Mate Search and Mate Choice.

Amount of calling activity (calling effort) is a strong determinant of male mating success in species such as orthopterans and anurans that use acoustic communication in the context of mating behaviour. While many studies in crickets have investigated the determinants of calling effort, patterns of variability in male calling effort in natural choruses remain largely unexplored. Within-individual variability in calling activity across multiple nights of calling can influence female mate search and mate choice strategies. Moreover, calling site fidelity across multiple nights of calling can also affect the female mate sampling strategy. We therefore investigated the spatio-temporal dynamics of acoustic signaling behaviour in a wild population of the field cricket species Plebeiogryllus guttiventris. We first studied the consistency of calling activity by quantifying variation in male calling effort across multiple nights of calling using repeatability analysis. Callers were inconsistent in their calling effort across nights and did not optimize nightly calling effort to increase their total number of nights spent calling. We also estimated calling site fidelity of males across multiple nights by quantifying movement of callers. Callers frequently changed their calling sites across calling nights with substantial displacement but without any significant directionality. Finally, we investigated trade-offs between within-night calling effort and energetically expensive calling song features such as call intensity and chirp rate. Calling effort was not correlated with any of the calling song features, suggesting that energetically expensive song features do not constrain male calling effort. The two key features of signaling behaviour, calling effort and call intensity, which determine the duration and spatial coverage of the sexual signal, are therefore uncorrelated and function independently.

Fat and sassy: factors underlying male mating success in a butterfly

AbstractTheory predicts that male mating success depends on resource holding potential (RHP), which is reflected by proxies of condition, such as body mass, fat content, strength, or weaponry. In species lacking any physical means to inflict injuries upon combatants, such as butterflies, the factors determining mating success are less clear. Against this background, we explored the determinants of male mating success in the tropical butterfly Bicyclus anynana Butler (Lepidoptera: Nymphalidae: Satyrinae), by comparing physiological, immunological, and morphological traits between winning and losing males. Our results showed that successful males are characterized by a better flight performance, evidenced by having longer wings, a heavier thorax, a lighter abdomen, a higher fat content, and higher phenoloxidase expression levels than their unsuccessful counterparts, when being compared after their first mating. Males that won three consecutive trials against the same combatant were also characterized by a better flight performance, having larger forewings, a higher body mass, and a higher fat content. Thus, successful males were larger and in better condition than unsuccessful ones. Strikingly, many differences found indicated an enhanced flight performance for the former, which we suggest ultimately plays the key role for male mating success in B. anynana. As fat is the main energy source for flying insects, being crucial to flight endurance and in turn presumably to male mating success, it may represent a key determinant at the proximate level.

Polyandrous mating in treetops: how male competition and female choice interact to determine an unusual carnivore mating system

The diversity of mammalian mating systems is primarily shaped by sex-specific reproductive strategies. In the present study, we explored determinants and consequences of a unique mating system exhibited by fossas (Cryptoprocta ferox), the largest Malagasy carnivore, where females mate polyandrously on traditional mating trees, and males exhibit intrasexual size dimorphism. Males face both contest and scramble competition, and inter-sexual size dimorphism can be pronounced, but its magnitude depends on the male morph. Using a continuous behavioral observation of six estrous females over 4 years, we investigated correlates of male contest competition and female choice based on 316 copulations. Furthermore, we assessed correlates of male scramble competition based on testes size and movement data obtained from GPS tracking. We found that females dominated males regardless of their smaller size and that females actively solicited copulations. Heavy males had highest mating success during the female’s peak mating activity, but were discriminated against afterwards. Female choice and male–male competition thus converged to generate a mating advantage for heavier males. Our results suggest that females actively seek polyandrous matings, presumably for indirect genetic benefits. Since body mass is the major determinant of male mating success and is at the same time dependent on the degree of sociality and associated hunting mode of the respective male morph, a male’s feeding ecology is likely to influence its reproductive tactic. A combination of benefits from female polyandry and the consequences of different subsistence strategies may thus ultimately explain this unusual mating system.

Effects of Age and Size on <I>Anopheles gambiae</I> s.s. Male Mosquito Mating Success

Before the release of genetically-modified or sterile male mosquitoes in an attempt to control local populations of malaria vectors, it is crucial to determine male traits involved in mating success. The effects of male size and age as determinants of male mating success in Anopheles gambiae s.s. were measured in the field and under laboratory conditions in Burkina Faso. First, the body sizes (estimated by wing length) of mating, swarming, and indoor-resting male mosquitoes were compared over a 3-yr period (2006-2009) from July to October in Soumousso and Vallée du Kou, two villages in western Burkina Faso. Second, the age structure of swarming and resting male mosquitoes were characterized based on the number of spermatocysts and the proportion of sperm in the reservoir of wild-caught male testis. Third, male age effects on the insemination rate of female An. gambiae were investigated in the laboratory. The mean size of males collected in copula was significantly larger than the mean for swarming males and indoor-resting males. The optimum male age for successful insemination of females was 4-8 d. These results suggest that male size is an important trait in determining male mating competitiveness in the field. Although age was not found to be a significant factor in mating competitiveness, it was significantly correlated with swarming behaviors in the field and insemination success in the laboratory. The implications of these results in terms of sexual selection in An. gambiae and vector control programs are further discussed.

Selection on floral traits through male fertility in a natural plant population

Most studies on selection in plants estimate female fitness components and neglect male mating success, although the latter might also be fundamental to understand adaptive evolution. Information from molecular genetic markers can be used to assess determinants of male mating success through parentage analyses. We estimated paternal selection gradients on floral traits in a large natural population of the herb Mimulus guttatus using a paternity probability model and maximum likelihood methods. This analysis revealed more significant selection gradients than a previous analysis based on regression of estimated male fertilities on floral traits. There were differences between results of univariate and multivariate analyses most likely due to the underlying covariance structure of the traits. Multivariate analysis, which corrects for the covariance structure of the traits, indicated that male mating success declined with distance from and depended on the direction to the mother plants. Moreover, there was directional selection for plants with fewer open flowers which have smaller corollas, a smaller anther–stigma separation, more red dots on the corolla and a larger fluctuating asymmetry therein. For most of these traits, however, there was also stabilizing selection indicating that there are intermediate optima for these traits. The large number of significant selection gradients in this study shows that even in relatively large natural populations where not all males can be sampled, it is possible to detect significant paternal selection gradients, and that such studies can give us valuable information required to better understand adaptive plant evolution.

Preferences of female barking treefrogs, Hyla gratiosa, for larger males: univariate and composite tests

Body size is an important determinant of male mating success, and acoustic signals often contain information about size. Most playback experiments that have tested for female preferences for larger males have manipulated only single characteristics, even though size is often correlated with multiple signal attributes. We first determined which characteristics of the advertisement calls of male barking treefrogs were correlated with body size, then we used two-choice playback experiments to determine whether female choice for larger males was influenced by these characteristics. In univariate tests, we varied only one of three size-correlated call parameters (fundamental frequency, call amplitude, call duration) at a time. In composite tests, we varied all three characteristics simultaneously, using univariate regressions of each parameter on size to predict the values expected for each characteristic for small, medium and large males. In univariate tests, females preferred large over small males for call amplitude and duration, medium over small males for amplitude and fundamental frequency, and large over medium males for call amplitude. In composite playbacks, females preferred large males over medium and small males, and medium males over small males. Females thus showed clear preferences for larger males, especially in the composite tests. Comparisons between the results of the univariate and composite tests indicated that female preferences for larger males are mediated by a combination of call characteristics rather than any single trait. Reliance on a combination of traits may function to increase the probability that females select larger males despite weak correlations between body size and individual call characteristics.

Determinants of male mating success in a natural population of a stream goby of the genus Rhinogobius

The mating success of individually identified males of a stream goby, Rhinogobius sp. CB (cross‐band type), was recorded over one breeding season. One to 3 year‐old males were active in mating, but 3 year‐old males, which accounted for 36% of the population, amounted to c. 70% of the total males guarding eggs in the nest. Three quarters of the breeding males had only one brooding cycle, but the others had two or three. All the latter males changed their nest sites between cycles within a riffle. In 1 and 2 year‐old males, the number of brooding cycles contributed more to the mating success than egg mass size in one brooding cycle. For mating success of 3 year‐old males, the egg mass size in one brooding cycle, which can be enhanced by spawning with a large female or multiple females, was as important as the number of brooding cycles. These male reproductive tactics could be attributed to the age‐related ability of nest construction and mate acquisition.

Male‐biased size dimorphism in ichneumonine wasps (Hymenoptera: Ichneumonidae) – the role of sexual selection for large male size

Abstract.  1. Sexual differences in body size are expected to evolve when selection on female and male sizes favours different optima.2. Insects have typically female‐biased size dimorphism that is usually explained by the strong fecundity advantage of larger size in females. However, numerous exceptions to this general pattern have led to the search for selective pressures favouring larger size in males.3. In this study, the benefits of large size were investigated in males of four species of ichneumonine wasps, a species‐rich group of parasitoids, many representatives of which exhibit male‐biased size dimorphism.4. Mating behaviour of all ichneumonine wasps are characterised by pre‐copulatory struggles, in the course of which males attempt to override female reluctance to mate. A series of laboratory trials was conducted to study the determinants of male mating success.5. A tendency was found for larger males as well as those in better condition to be more successful in achieving copulations. Size dimorphism of the species studied, mostly male‐biased in hind tibia length but female‐biased in body weight, indicates that sexual selection in males favours longer bodies and appendages rather than larger weight.6. The qualitative similarity of the mating patterns suggests that sexual selection cannot completely explain the considerable among‐species differences in sexual size dimorphism.7. The present study cautions against using various size indices as equivalents for calculating sexual size dimorphism.8. It is suggested that female reluctance in ichneumonine wasps functions as a mechanism of female mate assessment.

Do blood parasites affect reproductive performance in male red bishops (Euplectes orix)? A test of the Hamilton-Zuk hypothesis

According to the Hamilton-Zuk hypothesis of parasite-mediated sexual selection the expression of male secondary sexual characters as well as health and condition should be negatively affected by parasites. Over five breeding seasons we investigated the relationship between prevalence and intensity of blood parasites and reproductive performance as well as health state in male red bishops (Euplectes orix), a highly polygynous weaverbird species common in southern Africa. Neither prevalence nor intensity of infections with Plasmodium sp., the only blood parasite found in this study, were related to two important measures of male reproductive performance, i.e. the number of nests built (an intrasexually selected trait which is the most important determinant of male mating success) and the ability to establish a territory. In addition, parasite prevalence and intensity were not affected by season, time within season, age or body condition. These results do not support predictions derived from the Hamilton-Zuk hypothesis of parasite-mediated sexual selection. However, our data indicate that high stress levels as assessed by the heterophile/lymphocyte ratio might increase parasite susceptibility.

Male reproductive investment and queen mating-frequency in fungus-growing ants

Sperm number and male accessory gland compounds are often important determinants of male mating success but have been little studied in social insects. This is because mating in social insects is often difficult to manipulate experimentally, and first evidence for an explicit influence of accessory gland secretions on male mating success in social insects was obtained only recently. Here we perform a comparative analysis of male sexual organs across 11 species of attine fungus-growing ants, representing both genera with single- and multiple-queen mating. We found that the general morphology of the male sexual organs was very similar across all species, but the relative sizes of the accessory glands and the sperm-containing accessory testes vary significantly across species. Small testes and large accessory glands characterize species with singly mated queens, whereas the opposite is found in species with multiply mated queens. However, in the social parasite Acromyrmex insinuator, in which queens have secondarily reverted to single mating, males have accessory gland characteristics reminiscent of the lower attine ants, but without having significantly reduced their investment in sperm production. We hypothesize that the main function of accessory gland compounds in attine ants is to monopolize male paternity in similar ways as known from other social insects. This would imply that the evolution of polyandry in the terminal clade of the fungus-growing ants (the leafcutter ants) has resulted in selection for decreased investment by males in accessory gland secretions and increased investment in sperm number, in response to sperm competition for sperm storage.

Courtship tactics in garter snakes: how do a male's morphology and behaviour influence his mating success?

The behavioural determinants of male mating success play a pivotal role in sexual selection, but remain poorly known for most kinds of organisms, including most reptiles. In Manitoba, Canada, large numbers of red-sided garter snakes, Thamnophis sirtalis parietalis, court and mate in early spring near communal overwintering dens. To understand how a male's morphology and behaviour might influence his mating success, we videotaped 21 groups of snakes each comprising four males of varying body sizes plus a female. All males engaged in courtship, and mating occurred in all groups. Males with better body condition courted more vigorously and successfully than their smaller rivals did. The males that obtained matings were those that maintained their own cloaca closest to that of the female, aligned most of their body with the female, showed high rates of caudocephalic waving, chin pressing and tail searching, and did not allow other males to insert their body beside the female's. These behavioural differences between ‘winners’ and ‘losers’ were apparent from the beginning of each trial. Thus, male mating success in this ‘scramble’ system is determined not by chaotic, stochastic struggle (as has often been inferred) but instead is strongly linked to male courtship tactics. Energy stores (as evidenced by good body condition) may be critical determinants of mating success in these vigorous courtship episodes.

MORPHOMETRIC TRAITS AND SEXUAL SELECTION IN MEDFLY (DIPTERA: TEPHRITIDAE) UNDER FIELD CAGE CONDITIONS

The effects of male size and other morphometric traits as determinants of male mating success were evaluated under field cage conditions. Males of the laboratory Seib6-96 strain were released into field cages with males and females of a wild population from the Patagonian region. Mating pairs were classified as ‘successful’, while unmated flies were labeled as ‘unsuccessful’. Five morphometric traits were measured in a sample of 141 unsuccessful and 149 successful males: eye length (EL), head width (HW), thorax length (TL), face width (FW), and wing length (WL). An exploratory non-parametric Spearman’s rank correlation test indicated that mated males were in average larger for all traits (P < 0.01) except FW, indicating that with the exception of FW all traits are positively correlated with mating success. Step-wise multiple regression and principal component analysis logistic regression indicated that the most likely targets of selection were TL, EL, and FW. The two former are positively correlated, while FW is negatively correlated with the fitness component analyzed here (male mating success). In previous studies where male-male interaction had been removed experimentally, EL was shown to be associated with female choice and no effect relative to mating success was detected on TL. On the basis of that study and the present results it is tempting to suggest that body size (TL) might be important in intra-sexual selection. However, size was found to be strain dependent and flies from the wild were on average bigger than laboratory ones. Size selection might then be correlated with copulatory success, as a side effect due to selection of wild males over lab males due to differential sexual activity or other causes. The potential importance of both intra-sexual selection (male-male interactions) and inter-sexual selection (mate choice) on the morphology of Ceratitis capitata is discussed on the basis of the results presented here and previous works.

Environmental Effects on Male Reproductive Success and Parental Care in the Florida FlagfishJordanella floridae

Models of optimal parental care predict that parental investment should depend on offspring value or the effect parental care has on offspring benefits. Few studies have examined the effect of external factors that influence offspring survival and the cost of care. In this study on the Florida flagfish (Jordanella floridae), a species with male parental care, we examined whether environmentally induced changes in care result from changes in egg requirements or in parental costs. We manipulated salinity and temperature, as these factors are known to affect the metabolic rate in both eggs and parents. We predicted that if the change in care behavior is determined by costs to the male then it should be paralleled by changes in non‐egg‐directed behavior. Conversely, if egg‐directed behavior changes independently of other behavior it would suggest that behavior is determined primarily by egg requirements. In addition we examined patterns of mating success under the assumption that if male care is affected by environmental factors then female preferences may change accordingly. Males decreased egg‐directed behavior (fanning and cleaning of eggs) at high salinity. Non‐egg‐directed behavior was unaffected by salinity. Temperature had no effects on behavior. Thus, we conclude that changes in egg demands are primarily responsible for the observed results. Successful males were bigger and more aggressive. This suggests that male dominance was an important determinant of male mating success. Unsuccessful males showed significantly more variation in number of red stripes with respect to salinity than successful males. Unsuccessful males may be less able to regulate color expression under varying environmental conditions, in which case color may be an indicator of male quality. We replicated the experiment early and late in the season. Males did not change their effort in care over the season. However, care (fanning) in the absence of eggs increased towards the end of the season. Since pre‐mating fanning was positively correlated to a male’s eventual mating success we conclude that males increased their effort to attract mates late in the season.

Male-male competition for large nests as a determinant of male mating success in a Japanese stream goby, Rhinogobius sp. DA

Males of the stream goby Rhinogobius sp. DA (dark type) court females in deep pools and care for the eggs under stones in shallow riffles. We studied male–male competition for access to females and nest sites to understand how male size influences the mating success of this species. In field observations, larger males won in fighting with other males. However, large males did not tend to monopolize courtship opportunities, and the frequency of successful courtships, after which males led the females to the nests, was not related to male body size. The fact that courted females always escaped from the fighting sites once males began fighting likely explains why male size was not positively related to courtship success. Large males occupied large nest stones, and the number of eggs received in the nest was correlated positively with nest size. In aquarium experiments with two tiles of different sizes provided as nesting materials, males always chose the larger nest and, when two males were introduced simultaneously, the larger one occupied the larger nest. These results suggested that male mating success of this goby is determined by male–male competition for large nests rather than for access to females.

Determinants of male mating success in the red bishop ( Euplectes orix )

We studied sexual selection in the red bishop, Euplectes orix, a colonial, polygynous weaverbird widely distributed over sub-Saharan Africa. Male reproductive success measured in terms of the number of nests accepted by females and the number of eggs and nestlings in all the nests on a male's territory varied considerably. The standardized variance (variance/mean2) in male reproductive success ranged from 0.505 to 1.737 in different years, indicating a high potential for sexual selection in this species. An analysis of genetic parentage for 432 nestlings by non-radioactive, multilocus DNA fingerprinting confirmed that male reproductive success (number of young sired on the territory) in this species can be reliably estimated by the measures introduced above. In all 4 study years there was a strong positive correlation between male mating success and the total number of nests that males built in their territories. The number of nests built can be partitioned into the number of weeks a male held a territory and his nest-building performance. Both factors exert a significant positive effect on male mating success and in combination explained between 53.3 and 86.3% of the variation in male reproductive success. Male morphological characters were found to be of no importance. Males that established a territory in the following season built more nests and held their territories for longer than males that did not establish a territory in the following season, suggesting that these measures might be indicators of male condition and quality. Male nest-building performance (number of nests built per week) seems to be unrelated to male condition or quality.