Influence Mating Success Research Articles

Male nest building but not display behaviour directly influences mating success in the polygynous Red Bishop, Euplectes orix

Previous studies of the highly polygynous and strikingly sexually dimorphic Red Bishop, Euplectes orix (Ploceinae, weaverbirds), have suggested random female settlement patterns and no correlates of male reproductive success except the number of nest frames (‘cock's nests’) built by the male. Although this confirms the central role of the nest in weaverbird courtship it also contrasts with demonstrated sexual selection on male morphology and behaviour in several closely related Euplectes species. Two major aspects of male sexual advertising have not been included in previous studies; display behaviour and territory size. In this study we use multivariate selection analysis, with the number of active nests in a territory as the fitness measure, to identify direct and indirect sexual selection on male sexual behaviour, territory size and nest building. In accor–dance with previous findings, mating success was not strongly skewed among the territorial males, and females appeared to settle randomly with respect to available nests. The number of cock𠀧s nest built was the only determinant of male breeding success, even when controlling for male display activity and territory size. We argue that, despite their conspicuous sexual dimorphism, females settle independently of both male or territory quality, and that variance in male reproductive success is a consequence of male–male competition.

Mating aggregations and mating success in the flower thrips, Frankliniella schultzei (Thysanoptera: Thripidae), and a possible role for pheromones

Aggregations of Frankliniella schultzei males were observed on the corollas of Hibiscus rosasinensis and Gossypium hirsutum flowers in southeast Queensland. Aggregations were seen only on the upper surfaces of corollas but may have occurred on other flower parts, which were hidden from view. Conspecific females entered aggregations and a small proportion of them mated [18% (n = 163), H. rosasinensis; 30% (n = 181), G. hirsutum]. Most females (87 and 72%, respectively) that did not mate in aggregations walked to other flower parts. Behavior was difficult to observe on these parts, but mating was sometimes observed there. The number of females that landed within aggregations on the upper surfaces of both H. rosasinensis and G. hirsutum corollas was highly correlated with the number of males (r = 0.88, r = 0.93, respectively; P < 0.001). Significantly more mating pairs were observed in high-density aggregations (mean +/- SE, 1.10 +/- 0.22 and 4.44 +/- 0.48, respectively) than in low-density aggregations (0.37 +/- 0.11 and 1.67 +/- 0.29, respectively) (P < 0.05) on flowers of both species. More F. schultzei females were attracted to sticky traps baited with live conspecific males set among flowering Ipomoea indica (mean +/- SE, 8.83 +/- 0.32) and G. hirsutum (10.90 +/- 0.79) plants than to control traps (0.10 +/- 0.05 and 0.70 +/- 0.25, respectively)( P < 0.05), presumably in response to male-produced pheromones. Significantly more females were attracted to traps with high male densities than to traps with low densities. We found no statistical evidence that aggregation size influenced mating success (proportion males that mated). Mating success, however, should be evaluated with respect to mating on all flower parts and not just the upper surfaces of corollas. The results of this study constitute the first behavioral evidence for an attractant sex pheromone in thrips.

A novel mobile approach to investigating mating tactics in male grey seals (Halichoerus grypus)

AbstractStudies of the grey seal Halichoerus grypus mating system, using focal animal sampling constrained by study site location and size, limit the measurement of variation in male mating tactics and success. Using this method, the mating tactics of grey seal males have been classified as either ‘tenured’ or ‘transient’. Preliminary evidence is presented of wider variation in male mating tactics and success using mobile focal‐animal techniques that are not constrained by site, and of the effects of age on behaviour when accounting for body mass. The study was conducted during the breeding seasons of 1997 and 1998 at Sable Island, Nova Scotia. Six young (11–12 years) and five old (20–25 years) males were captured at the beginning of the breeding season, weighed and fitted with a VHF transmitter and time‐depth recorder. Each male was located daily, and a count of late‐lactating females within a 10 m radius recorded as a measure of mating potential. Female guarding and observed copulatory attempts were used as a measure of mating success. Mean initial body mass of young males and old males was similar, 291 ± 13 kg and 298 ± 14 kg, respectively. All males changed location during the study period. Young males changed sites more often and moved shorter distances between sites than old males. Estimated mating success varied from probably no matings to a minimum of seven; there were no differences between young and old males. Maximum duration of stay at a site and the number of late‐lactating females at a site significantly influenced mating success. All the males except for two young males departed on diving excursions during the breeding season and engaged in deep diving behaviour. Diving behaviour did not differ between the age classes. Our results indicate that the current classification of mating tactics in grey seal males is an oversimplification. Preliminary data show that age may account for some of the variation in male behaviour on land and mating success, but not for behaviour at sea.

Factors Influencing Mating Success, Mating Frequency, and Fecundity inPhthorimaea operculella(Lepidoptera: Gelechiidae)

The adult potato tuberworm, Phthorimaea operculella (Zeller), is a primary pest of potato plants. Studies were conducted to assess the possibility of applying sterile insect technique as an alternative control method against this pest. The purpose of this study was to examine the effects of adult age, weight, female mating status, and sex ratio on success and frequency of mating in P. operculella. The relationship between number of matings, fecundity, and fertility of females was also studied. A negative correlation was found between mating success and adult age. Female and male weights had an effect on the number of times individuals mate, but male weight only influenced mating success. Males mated more than once when confined with three virgin females for 24 h. Females did not mate more than once, even when they were confined with three virgin males. Males were more likely to mate with virgin females than with previously mated females. Multiply mated females and those which did not accept a second mating showed higher fecundity and fertility than their counterparts which were not given the opportunity to remate. Our results provide essential information necessary to increase the effectiveness of sterile insect technique as a control method against P. operculella.

SOCIAL DOMINANCE, MALE BEHAVIOUR AND MATING IN MIXED-SEX FLOCKS OF RED JUNGLE FOWL

In mixed-sex flocks of red jungle fowl (Gallus gallus), both males and females form dominance hierarchies, and male-male aggression and female choice can influence mating success. If females prefer the dominant male, there is no conflict between intra- and intersexual selection. We studied captive flocks consisting of two males and three females. In 1998, dominant males had larger combs than subordinate males in most flocks, while in 1999, comb size did not differ between dominant and subordinate males. The dominant male crowed more and performed more wing flaps than the subordinate male, but both males performed an equal number of tidbits and waltzes. The dominant male obtained more copulations than the subordinate male. When the dominant male had the larger comb, females of all ranks preferred to mate with and associated with the dominant male. When the subordinate male had the larger comb, primary and secondary females mated with the dominant male while tertiary females mated more often with the subordinate male, and female association with a male did not predict mating. Males with large combs are preferred by females and tend to become dominant, but females seem to prefer males with large combs even when these males are subordinate.

Why Do Black Grouse Males Perform on Lek Sites outside the Breeding Season?

Studies of sexual selection have focused mainly on explanations of how male characteristics influence mating success during the breeding season. By contrast, few studies have investigated how behaviours prior to the breeding season influence mate choice d

Mating success of male bushy-tailed woodrats: when bigger is not always better

To determine the factors that regulate mating opportunities of male bushy-tailed woodrats (Neotoma cinerea), we used stepwise multiple regression on measurable morphological and behavioral traits. DNA fingerprinting was used to determine the paternity of juveniles, allowing mating success (the number of females mated with), and reproductive success (the number of offspring fathered) to be quantified. Both measures of male success were significantly related to the growth rate of males while reproductively active. The most successful males were those that had higher growth rates, indicating that there is relatively little cost (weight loss) associated with successful mating in male woodrats. Our findings demonstrate that although this species is highly sexually dimorphic, large body size does not influence mating success. In addition, it appears that male mating success cannot be predicted from morphological measures and may instead be determined by behavioral or olfactory cues.

INTERACTION-INDEPENDENT SEXUAL SELECTION AND THE MECHANISMS OF SEXUAL SELECTION.

Darwin identified explicitly two types of sexual selection, male contests (combat and displays) and female choice, and he devoted the overwhelming majority of his examples to traits that influence the outcome of these interactions. Subsequent treatments of sexual selection have emphasized the importance of intra- and intersexual interactions as sources of sexual selection. However, many traits that are important determinants of mating success influence mating success without necessarily affecting the outcome of intra- and intersexual interactions. Here, I argue that traits can be subject to sexual selection even if they do not affect the outcome of intra- and intersexual interactions. I distinguish two types of sexual selection, interaction-independent and interaction-dependent selection, based on whether variance in mating success is the result of trait-dependent outcomes of interactions between conspecifics. I then use this distinction to construct a framework for classifying types of sexual selection that unifies and expands previously proposed frameworks. Finally, I outline several implications that the concept of interaction-independent sexual selection has for the general theory of sexual selection.

Do opercular flaps of male longear sunfish (Lepomis megalotis) serve as sexual ornaments during female mate choice?

Characteristics such as courtship displays and body size have been shown to influence mating success of male fishes. However, few examples of structural sexual ornaments exist, and ornamentation is typically limited to coloration. One possible example of a structural sexual ornament in fishes may be the exaggerated opercular flaps of male longear sunfish (Lepomis megalotis). We investigated female mate choice in two laboratory experiments by manipulating opercular flap lengths of males by clipping and by applying artificial extensions. Females spent significantly more time with, and displayed more to the longer-flapped males in both experiments. These results suggest that the opercular flaps of male longear sunfish may function as sexual ornaments.

Effects of Growth Rate on Variation in Breeding Coloration in Male Sand Lizards (Lacerta agilis: Sauria)

Sand lizards (Lacerta agilis) have color vision which is most sensitive in the wavelengths that correspond to the male breeding coloration (Swiezawska, 1949), and males with more green lateral breeding coloration (i.e., with larger badges) are more likely to win staged contests in the laboratory and have higher mating success in the wild (Olsson, 1992a, 1992b, 1993). Olsson and Madsen (1995) demonstrated that female sand lizards do not choose males, so breeding colors are not sexually selected via female choice. Instead, males seem to use the green badge to facilitate the judgment of a rival's fighting ability (Olsson 1994a). An interesting question is therefore, What factor(s) determine(s) badge size and prevent(s) males from cheating? (i.e., developing a too large or too bright badge to, ultimately, obtain more matings; see e.g., Maynard Smith, 1982). In other lizard species, androgens affect male breeding coloration (e.g., Cooper and Greenberg, 1992; Rand, 1992; Hews and Moore, 1994), which, hence, may influence mating success (Olsson 1994a). However, androgens may be costly to maintain at high plasma concentrations (Marler and Moore, 1989), and growth rate declines with body size and age (Olsson, 1994a). Thus, young, sexually mature males may allocate most energy and nutrients to growth rather than to reproduction and its associated expenditures. The aim of this study was to investigate whether growth rate affects breeding coloration, independent of testosterone and body size. Once sand lizard males emerge from hibernation in mid-April, they begin to develop breeding coloration and about two to three weeks later begin mating. The badge is temporally labile in sand lizards, and sexually mature males develop a badge that increases allometrically in relation to body size (Olsson, 1994a). When males are castrated after developing breeding coloration, they maintain their green color that year but fail to develop green coloration the following year (Regamy, 1935). We performed analyses on lizards kept in the laboratory and on which we monitored testosterone levels. This enabled us to tease apart the independent effect of growth rate on a component of breeding coloration while we statistically held plasma testosterone concentration constant at its mean in partial correlations.

Influence of management and environmental factors on mating success of Africanized queen honey bees

SUMMARYEnvironmental factors and management techniques were evaluated in São Paulo, Brazil, for enhanced production of Africanized queen honey bees. Queens were reared by the Doolittle method; 12 breeder, 6 cell-builder, and 36 3-frame nucleus colonies were used. Nine groups of four virgin Africanized queen honey bees were subjected to the following treatments: queens were either 1–2, 3–4 or 5–6 days old and were released into mating nuclei containing either capped brood, uncapped brood or no brood. This was repeated sixteen times between August 1990 and August 1992. Seven repetitions occurred during nectar flow periods and nine repetitions occurred during nectar-dearth periods. Overall, 59% of 576 queens were successfully introduced and mated. The best results (93% success) were obtained during nectar flows, with 3- to 4-day-old queens released into nuclei containing capped brood. During nectar dearths the best mating success came from queens introduced into broodless nuclei (63%), the age of the queen did not influence mating success. Mating success decreased when wind velocity increased; this was the only significant meteorological effect found.

Experimental and natural changes in the peacock's (Pavo cristatus) train can affect mating success

Petrie et al. (1991) demonstrated a correlation between the degree of elaboration of peacocks' trains and their mating success, and also showed that this correlation occurred because females preferred to mate with the male that had the most elaborate train of those sampled on the lek. Although these data suggest that female choice is responsible for non-random mating in this species, they do not conclusively show that train morphology is the cue that females respond to, because they do not rule out the possible influence of another unidentified variable which is correlated with train elaboration. This paper presents an experimental test of the importance of the peacock's train in determining male mating success. If the number or arrangement of eye-spots in the peacock's train influences mating success, then changing the number of eye-spots should change mating success. This prediction was tested in an experiment where the trains of male peafowl (Pavo cristatus) were manipulated by removing a number of eye-spots between mating seasons. Peacocks with eye-spots removed showed a significant decline in mating success between seasons compared with a control group. This result, together with the observational data, supports the hypothesis that the peacock's train has evolved, at least in part, as a result of female choice.

Genetic variability of courtship song in a population of Drosophila melanogaster

Abstract. The courtship song of male Drosophila melanogaster influences mating success and may have been involved in speciation within the melanogaster subgroup. The variability of two important parameters of this song, inter-pulse interval and hum-song frequency, within a large recent collection from a wild population, was examined. The phenotypic variability was low (coefficients of variation were 5·4 and 7·7%, respectively). Although there were indications of variability among males and families, the heritability of both parameters measured by father-son regression was not significant. Twenty isofemale lines from the same population were also examined after 30 generations of culture in the laboratory. These showed similar phenotypic variability, although a greater proportion of this was among families. A single generation of artificial selection showed that this variation included a genetic component which responded to selection. Reasons for the discrepancy between the results of the two studies are discussed. It is concluded that D. melanogaster song shows relatively low phenotypic and additive genetic variability, which is consistent with most expectations for an important mating signal. However, the character can evolve following genetic drift, probably because of non-additive sources of genetic variation in the original population.

Invasion and Maintenance of Alleles that Influence Mating and Parental Success

Here we develop a model of the invasion, polymorphism, fixation and extinction analysis of genes that differentially influence the mating and parenting success of the two sexes. The model could have application, for example, to the maintenance of homosexuality in diploid populations. The analysis focuses on systems in which mating success is density-dependent and contrasts the results with the density-independent case. Five situations are analyzed, including cases where male and female parenting success is affected in the same and in different directions by the alleles in question. As part of the analysis, a technique is outlined for identifying boundaries between regions where polymorphisms occur and regions where the alleles under consideration go either to fixation or extinction. The results indicate that, unlike in the density-independent case, in the density-dependent case the degree of dominance of the types of alleles analyzed here critically determines whether such alleles are able to invade a population, exist as a polymorphism, or go to fixation.

Male‐male competition and mating success in the orb‐web spider, Nephila clavata, with reference to temporal factors

AbstractSeasonal occurrence patterns of adults of both sexes, intensity of male‐male interactions, and mating success in the spider, Nephila clavata, were examined in the field. Adult males began to attend female webs about 2 weeks before female maturation. Large adult males were abundant in the early breeding season, but small males increased later in the season. From the distribution of males among female webs and size relationship of males within a web, male‐male interactions seemed to be more intense when most females were still subadult. This was verified by a field experiment in which males were artificially introduced to female webs that were attended by other males. It was found that the probability of introduced males remaining on subadult female webs was lower than that on adult webs. As mating occurred mostly in the period shortly after the female final molt and first male sperm precedence was known in all spiders reported so far, intense male‐male competition on subadult female webs seemed to be reasonable. Male longevity had an important influence on the mating success of males with just‐molted females. Mating success was also affected by the relative body size of males present in a given period. Since larger males occupied the position closest to females within a web and stayed there longer, relative body size appeared to influence mating success through male‐male competition. Female body size at maturation declined with time; hence, males that attained sexual maturity earlier had the advantage of mating with larger and more fecund females. Therefore, early maturation as well as larger size seem to be two important trairs influencing the reproductive success of males.

Positive allometry is likely with mate choice, competitive display and other functions

Petrie (1988) argued that structures important in displaying competitive ability between individuals should be developed in a positively allometric manner in species where large animals usually win fights, with larger animals developing relatively larger structures, as with the frontal shield of the moorhen, Gallinula chloropus. Petrie's reasoning is that animals of low competitive ability have little to gain from paying the costs of developing a large structure because any structure advertising low ability will do little to reduce the number and/ or intensity of contests. In contrast, characters important in mate choice are considered unlikely to be positively allometric. Referring to moorhen shields, Petrie said 'If shields were important in mate choice it is hard to see why they should be positively allometric, since it would pay all individuals to invest maximally in structures that advertise their quality as mates, and this would result in shields being isometric.' In my view, positive allometry will often occur in characters used in mate choice or with various other functions, and is therefore not evidence that a character is used to display competitive ability. As animals grow, they will partition investment into both bodies and characters so that bigger animals have bigger characters. How much bigger they are will depend on both the costs and benefits of a larger body size, and the costs and benefits of a larger character. The key question is, as an animal acquires more resources to invest in growth, how much should it invest in the character and how much in body size? Positive allometry will result if the net benefit of larger characters increases faster than the net benefit of larger bodies. Negative allometry will result if the net benefit of larger characters increases more slowly. In other words, if the same resource investment into a character or body size brings a greater net benefit from the former, that is where investment will be concentrated, resulting in positive allometry. If, however, a greater net benefit comes from the latter, negative allometry will result. This applies to characters with mate choice, competitive display or any other functions. A character developed for mate attraction may be positively allometric for at least two reasons. First, smaller animals may be less able to obtain mates and so have little to gain from paying the costs of developing a large character that does little to increase the number of matings. This logic is similar to that used by Petrie (1988) for characters displaying competitive ability, and will apply whether body size influences mating success through intersexual competition or mate choice. There may be cases where competition between males prevents small males from gaining access to females, while females choose males with larger characters (e.g. in the pinyon jay, Gymnorhinus

Levels of Female Choice in the White-Tailed Skimmer Plathemis Lydia (Odonata: Libellulidae)

AbstractMale Plathemis lydia defend mating territories along the perimeter of ponds. Females come to ponds for brief periods of time every few days to oviposit. During these visits, females actively discriminate among males, rejecting up to 48.9 % of mating attempts. Males varied significantly in the proportion of attempts successfully leading to copulation. However, males that obtained more matings also experienced more rejections. Extensive analyses based on absolute male size, relative male size, and male size relative to female size yielded only marginally significant evidence of female mate preference based on body mass, wing length, wing loading index, or age; to the extent that any of these characters appeared to influence mating success, they similarly influenced refusal rates. The overall weakness of female mate choice is further suggested by the frequency of females ovipositing without prior matings and by the low frequency with which females remate with the same males. On a population basis, females strongly prefer to oviposit in the middle of the day and at particular parts of the study pond. Thus, females exhibit strong choice at several levels. However, despite the high incidence of active female rejection and high variance in male mating success, mate choice is apparently of minor importance in this population. Female discrimination of males, combined with variance in male mating success, are necessary but not sufficient for the action of sexual selection via mate choice. These findings support the prediction that male-male competition is of primary importance in resource control mating systems in which males are able to control female access to most or all favored oviposition sites. However, it is not clear why females generally fail to discriminate among males, given that they have the opportunity to do so. In general, females appear to have low motivation to mate with males, presumably because multiple mating does not significantly increase their fertility or fecundity. Selection for rapid mating may be significant, both because of predation on females during mating and oviposition and because of the risks for males of losing their territories during mating bouts. This time constraint may be the most important factor limiting female discrimination among males on the basis of consistent characteristics.

The Behavioral Ecology of Libellula luctuosa (Burmeister) (Odonata: Libellulidae)

AbstractIn a pond dragonfly, Libellula luctuosa, the number of males at the mating site increased linearly during mating seasons. The number of fertilizable females in the population did not increase. An increasingly male biased operational sex ratio (OSR) therefore correlated with the increasing density of males. I predicted that this would cause increased male‐male competition and alter female mate choice.Competition for territories influenced mating success in L. luctuosa. Two different mating strategies were adopted by males of L. luctuosa: some flew and defended lengths of shoreline (territorial males), and some perched and avoided male‐male interactions (satellite males). Satellite males increased later in the season when all territories were occupied. However, no satellite ever switched to the territorial strategy and no territorial male ever became a satellite. At high male density, two males occasionally defended the same territory. The occupation of territories was nonrandom. The probability of any male mating depended on the time of year. Territory owners did most of the mating; satellite males rarely mated. Postmating guarding of females by males depended on the number of conspecific males present.Mating success of males was also influenced by female mating behavior, and female mating behavior was influenced by the number of males present. Females visited several males prior to mating. When fewer males were present females were more likely to reject male mating attempts. The length of copulation did not change during the mating season. At high male density, females spent less time ovipositing immediately after mating. Postcopulatory mate guarding by males increased the length of time the female spent ovipositing. These behavioral patterns may represent different strategies of mate choice, precopulatory mate choice at low male density and postcopulatory mate choice at high male density.

Ornament size influences mating success in male rock ptarmigan

Factors influencing male mating success in a natural population of rock ptarmigan, Lagopus mutus, were examined. In the first year of study, 1984, a survey of mating patterns revealed bigamous, monogamous and bachelor males in the population. In that year, males with the largest supraorbital combs had the most mates. After males were paired in 1984, they were captured and banded with a unique sequence of coloured leg bands for future identification. The following year, returning males with combcoloured bands were more successful at obtaining mates than were males with similar comb size but without these band colours. These results suggest that among rock ptarmigan, the comb is a target of sexual selection and that a novel, non-genetic trait, when similar in colour to the target, can also influence a male's mating success.

Minority mating advantage of certain eye color mutants of Drosophila melanogaster. IV. Female discrimination among three genotypes.

It was our purpose to examine how the courtship sequence by three eye color types of males inDrosophila melanogaster might affect the experience of females in such a way as to influence mating success. Flies were mutants for a pair of alleles at thebrown locus (bw andbw75; 104.5 on chromosome 2) combined withscarlet (st; 44.0 on chromosome 3). Mutant red-eyed (R), orange-eyed (O), and white-eyed (W) flies were tested, mature virgin females individually in the presence of six males, either three each of two eye color types or two each of three types. About 12% of the females displayed a low threshold and mated to the first male that courted in less than 5 min. For these females and for those with a higher threshold when courted by one type of male only, R males were twice as successful as O and about four times as successful as W. For trials in which two male types courted, females tended to accept the type that was not the first to court in 62.5% of the trials with a 3∶3 ratio of males and in 70% of the trials with a 2∶2∶2 ratio but one type of male not courting. When all three types of males courted at the latter ratio, females tended to discriminate against both the first type to court and the joint combination of first with second type to court, tending to mate with the third type in 47% of the trials. There was no significant association between either the second male or the second type of male to court and the type that mated. Evidence is presented that the visual component of courtship is important to persistence and efficiency but less important to initiation of courtship. The time to mating (female acceptance) is longer with increase in the number of male types courting. These results and some arguments by other authors trying to account for negative results using the same mutants are discussed. We conclude that sexual behavior is controlled by loci other than those markers determining eye colors tested, and the genetic background for the mutant phenotypes is most critical for female discrimination.