Courtship Success Research Articles

Damselfly females prefer hot males: higher courtship success in males in sunspots

Males of some territorial calopterygid damselflies show an elaborate courtship display that involves high-frequency wing-beats directed toward an incoming female. Although it has been suggested that female mate preference is based on some characteristics of male’s courtship display, it is unclear whether the courtship display varies between males or is influenced by environmental conditions. We combined two recent technologies, thermographic imaging and high-speed digital videography, to show that the wing-beat frequency during courtship (i.e., courtship intensity) in a damselfly, Mnais costalis, is correlated with thorax temperature. Our data indicated that (1) male thorax temperature was associated with solar exposure in his territory, (2) environmentally derived thermal gain enhanced courtship intensity, (3) hotter males were more likely to copulate than others, and (4) female thorax temperature during oviposition within a territory was associated with solar exposure. Males with territories that have longer exposure to sun spots are expected to attain higher thorax temperatures for longer and so are able to successfully court more females. We suggest that females benefit from mating with hot males because they will be on a warmer territory while ovipositing. Hot males might also have greater mate guarding ability, and/or eggs may develop faster in warmer territories.

Courting Failure in a Pencilfish, Nannostomus b. beckfordi

We analysed a sample of 4341 activity bouts from 12 male Nannostomus b. beckfordi interacting with ♀♀. Only 22 % of the gamopractic bouts ended in spawning. In 50 % of the bouts the pair separated without spawning or interference, partly as a result of male aggression. Interference frcm conspecifics was also a major cause of failure, terminating 28 % of the gamopractic bouts. Successful courtship bouts contain more gamopractic behaviour than do abortive bouts, even in the first 6 s, and also show greater stereotypy.

Competitive Mating Success and Attractiveness of Sterile and Fertile Males of Drosophila montana

The attractiveness and the mating success of fertile (normal and brownie, br) and sterile (rudimentary testis, rt) Drosophila montana males were studied in female-choice experiments (one female + two males). The normal males courted the sterile rt males nearly as much as they courted the females, while they courted other males less frequently. The females required a long courtship with the rt males and accepted them as their mating partner less often than normal males. The courtship behaviour of normal, br and rt males was recorded in single pair situations with a normal female. The courtships of the males of all types proceeded in a similar manner, but the successful courtships of the rt males included more licking and touching than those of the normal and br males. The licking and touching periods are probably the critical phases at which the females are able to detect differences in male fertility.

Acoustic courtship songs in males of the fruit fly Anastrepha ludens (Diptera: Tephritidae) associated with geography, mass rearing and courtship success

The Sterile insect Technique (SiT) has been used successfully to control or eradicate fruit flies. The commonly observed inferiority of mass-reared males, compared with wild males, when they are paired with wild females, is apparently due to their inadequate courtship. Anastrepha ludens males produce two types of wing vibration during courtship and mating, the sound and the or precopulatory sound. There were clear differences in the calling songs between successful and unsuccessful courtships in sterile (irradiated) and fertile Mexican flies. Among sterile flies, successful males produce longer buzzes, shorter interpulses and a higher power spectrum in the signal. Fertile flies showed the same trend. For mating songs a significant dif- ference occurred in two parameters: power spectrum between sterile and fertile flies with respect to the type of song, and the signal duration and intensity were greater in non-irradiated flies. Calling songs of wild flies compared with laboratory grown flies from Mexico had shorter interpulses, longer pulses, and a greater power spectrum. However, in the case of premating songs, the only difference was in the intensity, which was sig- nificantly greater in wild males. An unexpected result was not observing pulses during pheromone deposition in wild males from Costa Rica. Comparing the premating songs of wild flies from Costa Rica and Mexico, no significant differences were observed in the duration, and the intensity of the signal was slightly greater in flies from Mexico. Rev. Biol. Trop. 57 (Suppl. 1): 257-265. Epub 2009 November 30.

Independence of Sexual and Anti-Predator Perceptual Functions in an Acoustic Moth: Implications for the Receiver Bias Mechanism in Signal Evolution

The receiver bias model for the evolution of mating signals proposes that selection favors male displays that happen to stimulate a general, ancestral perception in females such that receptivity and successful courtship increase. If these male signals do arise, however, the female perception will operate in two contexts, the original, typically non-sexual, one and courtship. We may then ask whether these two functions represent the same or distinct traits, which may be under separate neural and genetic control. We studied this question in Achroia grisella, a pyralid moth species in which males attract females, with an ultrasonic mating song. Hearing in pyralid moths is widespread and originated in an anti-predator context ‐ the perception and avoidance of echolocating bats ‐ and it is inferred that the male song found in A. grisella, and in several other pyralid species, arose subsequently via a receiver bias mechanism: Females perceiving male-produced ultrasound and responding with anti-predator behavior normally exhibited in the presence of bat echolocations may have inadvertently increased the likelihood of successful courtship. We measured hearing responses in both sexual and anti-predator contexts in inbred lines developed from an A. grisella population. Significant inter-line variance was observed for sensitivity thresholds for female response to male song and for both female and male responses to synthetic bat echolocation signals. Female responses to male song and to synthetic echolocations differed markedly in sensitivity, and the median sexual and anti-predator responses in the various lines were not correlated. However, a higher level of similarity occurs between the female and male anti-predator responses. Thus, genetic variance for sexual and anti-predator responses appears to exist, and the two responses may represent independent traits. These results imply that when male signals originate via a receiver bias mechanism, female perception does not necessarily remain fixed in its ancestral state but has the potential for continued modification.

Complementary/alternative medicine: engulfed by postmodernism, anti-science and regressive thinking

<h3>Abstract</h3> It is the female response to male signals that determines courtship success. In most songbirds, females control reproduction via the copulation solicitation display (CSD), an innate, stereotyped posture produced in direct response to male displays. Because CSD can be elicited in the absence of males by the presentation of recorded song, CSD production enables investigations into the effects of underlying signal features and behavioral state on female mating preferences. Using computer vision to quantify CSD trajectory in female brown-headed cowbirds (<i>Molothrus ater</i>), we show that both song quality and a female’s internal state predict CSD production, as well as the onset latency and duration of the display. We also show that CSD can be produced in a graded fashion based on both signal strength and internal state. These results emphasize the importance of underlying receiver state in determining behavioral responses and suggest that female responsiveness acts in conjunction with male signal strength to determine the efficacy of male courtship.

Male mating preference is associated with risk of pre-copulatory cannibalism in a socially polymorphic spider

We performed male attraction experiments and staged courtship sequences to test for non-random mating with respect to social behavioral phenotype in the comb-footed spider, Anelosimus studiosus. While asocial behavior is the dominant phenotype in all A. studiosus populations examined to date, a social phenotype approaches a frequency of 15% in colder environments. We collected test subjects from higher latitude polymorphic populations and scored all individuals as to their behavioral phenotype prior to their use in these trials. Males of both phenotypes differentially approached and courted social females over asocial females and no-spider controls. By offering males different numbers of females of one type vs. the other in subsequent trials, we determined that the difference in attractiveness between the two phenotypes social/asocial is 1.5/1. Both the web produced by a female and a female that has been removed from its web attract males. We suggest that the male attracting pheromone is present on females and is also attached to silk threads. Staged encounters completed between males and females of the respective phenotypes demonstrated that courting males suffer significantly less pre-copulatory sexual cannibalism with social females than with asocial ones, and thus, female social tendency is phenotypically linked to sexual aggression. We propose that the male preference for social females is adaptive because of the observed asymmetry in courtship success.

GENETICS OF INCIPIENT SPECIATION INDROSOPHILA MOJAVENSIS:II. HOST PLANTS AND MATING STATUS INFLUENCE CUTICULAR HYDROCARBON QTL EXPRESSION AND G × E INTERACTIONS

We performed a quantitative trait locus (QTL) analysis of epicuticular hydrocarbon variation in 1650 F(2) males from crosses of Baja California and mainland Mexico populations of Drosophila mojavensis cultured on two major host cacti. Principal component (PC) analysis revealed five PCs that accounted for 82% of the total epicuticular hydrocarbon variation. Courtship trials with mainland females were used to characterize hydrocarbon profiles of mated and unmated F(2) males, and logistic regression analysis showed that cactus substrates, two PCs, and a PC by cactus interaction were associated with mating success. Multiple QTLs were detected for each hydrocarbon PC and seven G x E (cactus) interactions were uncovered for the X, second, and fourth chromosomes. Males from the courtship trials and virgins were used, so "exposure to females" was included as a factor in QTL analyses. "Exposed" males expressed significantly different hydrocarbon profiles than virgins for most QTLs, particularly for the two PCs associated with mating success. Ten QTLs showed G x E (exposure) interactions with most resulting from mainland genotypes expressing altered hydrocarbon amounts when exposed to females compared to Baja genotypes. Many cactus x exposure interaction terms detected across QTL and all PCs confirmed that organ pipe-reared males expressed significantly lower hydrocarbon amounts when exposed to females than when reared on agria cactus. Epicuticular hydrocarbon variation in D. mojavensis is therefore a multigenic trait with some epistasis, multiple QTLs exhibited pleiotropy, correlated groups of hydrocarbons and cactus substrates determined courtship success, and males altered their hydrocarbon profiles in response to females.

Male Siamese Fighting Fish, Betta splendens, Increase Rather than Conceal Courtship Behavior when a Rival is Present

AbstractThe impact of social environment on mating success is especially pronounced in species where both intraspecific and interspecific selection influence reproduction, such as the Siamese fighting fish. Males alter male–male interactions when either a male or female audience is present, but how males change their behavior toward a female when a rival male is present is unknown. This study addresses whether males alter their behavior toward a female in a way that would prevent a rival male from interrupting courtship. The behavior of male Siamese fighting fish toward a dummy female was examined under various degrees of visual cover, both in the presence and absence of a rival male, to investigate whether males use concealment provided by the structural environment to their advantage. While males did not use barriers to conceal courtship as hypothesized, males altered their behavior by increasing courtship and monitoring their nest when a rival was visible. This increase in courtship is in contrast to most studies on courtship in the presence of a rival that find a reduction in courtship behavior. Males spent more time opercular gill flaring when no barriers were present, suggesting that males may be trying to court the female and communicate to the rival simultaneously. There was also a trend for aggression toward the female and the rival to decrease as screen length increased. Thus, males compensate for the presence of a rival by adjusting their courtship and aggressive behaviors, which could have important implications for courtship success.

Success of mutant Drosophila at different sex ratios

Relative courtship success of mutant Drosophila melanogaster males was found to vary with sex ratio. Males with one of three recessive mutants: White, vermilion, or vestigial, competed with wild type males for females. Female-biased sex ratios were associated with increased success of all three different mutant phenotypes relative to wild-type as compared to an unbiased sex ratio. There was no difference in the success of mutant males in the first or second half of the observation periods, which spanned one hour.

The Sex-Determination Genes fruitless and doublesex Specify a Neural Substrate Required for Courtship Song

SummaryCourtship song is a critical component of male courtship behavior in Drosophila, making the female more receptive to copulation and communicating species-specific information [1–6]. Sex mosaic studies have shown that the sex of certain regions of the central nervous system (CNS) is critical to song production [7]. Our examination of one of these regions, the mesothoracic ganglion (Msg), revealed the coexpression of two sex-determination genes, fruitless (fru) and doublesex (dsx). Because both genes are involved in creating a sexually dimorphic CNS [8, 9] and are necessary for song production [10–13], we investigated the individual contributions of fru and dsx to the specification of a male CNS and song production. We show a novel requirement for dsx in specifying a sexually dimorphic population of fru-expressing neurons in the Msg. Moreover, by using females constitutively expressing the male-specific isoforms of fru (FruM), we show a critical requirement for the male isoform of dsx (DsxM), alongside FruM, in the specification of courtship song. Therefore, although FruM expression is sufficient for the performance of many male-specific behaviors [14], we have shown that without DsxM, the determination of a male-specific CNS and thus a full complement of male behaviors are not realized.

GENETICS OF INCIPIENT SPECIATION INDROSOPHILA MOJAVENSIS. I. MALE COURTSHIP SONG, MATING SUCCESS, AND GENOTYPE X ENVIRONMENT INTERACTIONS

Few studies have examined genotype by environment (GxE) effects on premating reproductive isolation and associated behaviors, even though such effects may be common when speciation is driven by adaptation to different environments. In this study, mating success and courtship song differences among diverging populations of Drosophila mojavensis were investigated in a two-environment quantitative trait locus (QTL) analysis. Baja California and mainland Mexico populations of D. mojavensis feed and breed on different host cacti, so these host plants were used to culture F2 males to examine host-specific QTL effects and GxE interactions influencing mating success and courtship songs. Linear selection gradient analysis showed that mainland females mated with males that produced songs with significantly shorter L(long)-IPIs, burst durations, and interburst intervals. Twenty-one microsatellite loci distributed across all five major chromosomes were used to localize effects of mating success, time to copulation, and courtship song components. Male courtship success was influenced by a single detected QTL, the main effect of cactus, and four GxE interactions, whereas time to copulation was influenced by three different QTLs on the fourth chromosome. Multiple-locus restricted maximum likelihood (REML) analysis of courtship song revealed consistent effects linked with the same fourth chromosome markers that influenced time to copulation, a number of GxE interactions, and few possible cases of epistasis. GxE interactions for mate choice and song can maintain genetic variation in populations, but alter outcomes of sexual selection and isolation, so signal evolution and reproductive isolation may be slowed in diverging populations. Understanding the genetics of incipient speciation in D. mojavensis clearly depends on cactus-specific expression of traits associated with courtship behavior and sexual isolation.

The Payoff of Fighting in House Crickets: Motivational Asymmetry Increases Male Aggression and Mating Success

AbstractMotivational asymmetry caused by differences in subjective resource value is a key component of strategic models of aggression. We study the role of motivational asymmetry in determining differential aggression and mating success of male house crickets, Acheta domesticus. We also assess the extent to which mating differences associated with motivational asymmetry are due to direct male–male fighting vs. male–female interactions. We manipulated male motivation to compete for a mating opportunity by providing males with either no access or nightly access to females for 4 d prior to the experiment. As predicted, when males from each treatment had to compete for the female, those with lower prior access were more aggressive and mated more often. In contrast, when males from each treatment were paired individually with females, there was no significant difference in the frequencies with which they pursued, courted or mated with females. We also found no evidence for female choice based on motivational asymmetry; the rate of successful courtship did not differ between treatments. We conclude that prior mate encounter rate can generate motivational asymmetry, leading to differential mating success mediated by direct male–male aggression.

Female rock sparrows (Petronia petronia), not males, respond differently to simulations of different courtship interaction outcomes

AbstractAnimals communicate in networks which spread beyond the classic sender-receiver dyad. Researchers have often concentrated on networks of signalling males, but the network-level effects of male-female signalling interactions are largely unexplored, even though these can contain information when individuals of both sexes have access to a range of mating strategies. We tested whether rock sparrows (Petronia petronia) behave differently after hearing playbacks of vocal interactions simulating a successful courtship as opposed to playback of an unsuccessful courtship. We found no support for our prediction that males which heard a successful courtship simulation would increase the frequency of sexual behaviours compared with those which heard the unsuccessful courtship. Females which heard the successful courtship simulation stayed longer at the nest site and inside the nest box compared with those which heard the unsuccessful courtship simulation. Therefore, females responded to the treatments as if these represented different degrees of competition for either mates or nest sites. This is, to the best of our knowledge, among the first experimental demonstrations that female birds intercept signalling interactions between males and females and suggests that information available through communication networks can be relevant for an animal's choice of breeding strategy.

Multimodal signalling: structural ultraviolet reflectance predicts male mating success better than pheromones in the butterfly Colias eurytheme L. (Pieridae)

In sexual selection, multimodal signals elicit mate choice when more than one sensory modality is activated. However, determining the relative use of each signal is difficult because it requires a comprehensive understanding of the mating system and how this system works under natural conditions. We examined the role of structural ultraviolet (UV) reflectance and pheromones in the butterfly Colias eurytheme. Both traits are important in mediating interspecific interactions and pheromones have been implicated in intraspecific mate choice. UV reflectance, which arises from the presence of a multilayer thin-film interference array, has potential as an honest indicator of male condition, viability and/or age. We investigated the relevance of these signal traits to courtship success by releasing virgin females in the path of free-flying males until each female had rejected and accepted at least one male. This design facilitated a within-subjects (females) analysis of mate choice, thus controlling for potentially confounding variation in intrinsic female receptivity. Principal component analysis indicated that variation across males in UV brightness and pheromones was essentially orthogonal. Females preferred younger males (as subjectively adjudged by wing wear), and while age covaried with UV brightness and almost all pheromone descriptors, UV brightness emerged as the best and most general predictor of male mating success. Our results suggest that this trait serves as an important intraspecific sexual signal in C. eurytheme, and they provide the clearest evidence to date regarding the functional relevance of structural coloration to female mate choice in butterflies. We discuss the preferential use of one secondary sexual characteristic (UV reflectance) over another (pheromones) with regard to evolutionary strategies.

EFFECTS OF NATURAL AND SEXUAL SELECTION ON ADAPTIVE POPULATION DIVERGENCE AND PREMATING ISOLATION IN A DAMSELFLY

The relative strength of different types of directional selection has seldom been compared directly in natural populations. A recent meta‐analysis of phenotypic selection studies in natural populations suggested that directional sexual selection may be stronger in magnitude than directional natural selection, although this pattern may have partly been confounded by the different time scales over which selection was estimated. Knowledge about the strength of different types of selection is of general interest for understanding how selective forces affect adaptive population divergence and how they may influence speciation. We studied divergent selection on morphology in parapatric, natural damselfly (Calopteryx splendens) populations. Sexual selection was stronger than natural selection measured on the same traits, irrespective of the time scale over which sexual selection was measured. Visualization of the fitness surfaces indicated that population divergence in overall morphology is more strongly influenced by divergent sexual selection rather than natural selection. Courtship success of experimental immigrant males was lower than that of resident males, indicating incipient sexual isolation between these populations. We conclude that current and strong sexual selection promotes adaptive population divergence in this species and that premating sexual isolation may have arisen as a correlated response to divergent sexual selection. Our results highlight the importance of sexual selection, rather than natural selection in the adaptive radiation of odonates, and supports previous suggestions that divergent sexual selection promotes speciation in this group.

EFFECTS OF NATURAL AND SEXUAL SELECTION ON ADAPTIVE POPULATION DIVERGENCE AND PREMATING ISOLATION IN A DAMSELFLY

The relative strength of different types of directional selection has seldom been compared directly in natural populations. A recent meta-analysis of phenotypic selection studies in natural populations suggested that directional sexual selection may be stronger in magnitude than directional natural selection, although this pattern may have partly been confounded by the different time scales over which selection was estimated. Knowledge about the strength of different types of selection is of general interest for understanding how selective forces affect adaptive population divergence and how they may influence speciation. We studied divergent selection on morphology in parapatric, natural damselfly (Calopteryx splendens) populations. Sexual selection was stronger than natural selection measured on the same traits, irrespective of the time scale over which sexual selection was measured. Visualization of the fitness surfaces indicated that population divergence in overall morphology is more strongly influenced by divergent sexual selection rather than natural selection. Courtship success of experimental immigrant males was lower than that of resident males, indicating incipient sexual isolation between these populations. We conclude that current and strong sexual selection promotes adaptive population divergence in this species and that premating sexual isolation may have arisen as a correlated response to divergent sexual selection. Our results highlight the importance of sexual selection, rather than natural selection in the adaptive radiation of odonates, and supports previous suggestions that divergent sexual selection promotes speciation in this group.

Male satin bowerbirds, Ptilonorhynchus violaceus, adjust their display intensity in response to female startling: an experiment with robotic females

Females of many species preferentially mate with males that produce courtship displays at a high intensity or rate; however, males do not always display at their maximum intensity during courtship. Evidence suggests that this behaviour may be adaptive in satin bowerbirds, because overly intense displays can disrupt courtship by startling females. Females signal the display intensity that they will tolerate from a male; males that respond by adjusting their intensity reduce the likelihood of startling females and increase their courtship success. However, even the most responsive males occasionally startle females. When this occurs, males could avoid further threat to females by decreasing the intensity of their subsequent displays. We used robotic female bowerbirds that mimicked female startling to test the hypothesis that males reduce the intensity of their courtship displays after startling females. Supporting this hypothesis, males displayed at significantly lower intensity after robots were startled in experimental treatments than when they were not startled in control treatments. We found no evidence that the degree of male response to startling was related to male courtship success. In spite of evidence that female bowerbirds prefer the most intensely displaying males as mates, we found that males did not always display at maximum intensity, but rather reduced their intensity in response to female startling during courtship. Our results suggest that males adjust the level of expression of their display traits in response to female behaviours during courtship, and by doing so, males may increase their chances for successful courtship.

COURTSHIP OF THE TWO FEMALE MORPHS OF MELITTOBIA DIGITATA (HYMENOPTERA: EULOPHIDAE)

Abstract Courtship of sib-mating Melittobia digitata Dahms, a parasitoid of solitary wasps and bees, is reviewed, described, and quantified for 125 virgins of the non-dispersing brachypterous female (BF) morph paired with 24 experienced males, and for 158 virgins of the dispersing macropterous female (MF) morph paired with 21 males. Males performed 1-5 courtship bouts with both morphs; about half of all successful matings in both occurred after a single bout. Depending on number of bouts performed, mean courtship durations ranged from 47-268 sec for MFs and 59-277 sec for BFs. Courtship success rates were greater for BF couples (80%) than for MF couples (57%). Compared to BF couples, MF couples were more apt to undergo multiple bouts. Results are interpreted in the context of the morphs life history and the costs/benefits of alternatives. Failure to initiate any courtship during the 15-min observation period (22% for MF pairs, 21% for BF pairs) appeared to be due to apparent lack of interest or to...

The Role of Male Courtship Song in Species Recognition in Drosophila montana

In many Drosophila species the male courtship song is an essential part of a successful courtship, playing a role in species-recognition and/or in sexual selection exercised by the females on conspecific males. In Drosophila montana, specific traits of the courtship song (the length and the carrier frequency of sound pulses) have earlier been shown to play an important role in intraspecific mate choice. Here we show that the male song (especially the interpulse interval) also plays a role in species-recognition, maintaining sexual isolation between sympatric species. We succeeded in breaking down sexual isolation between D. montana females and D. lummei males by playing the females simulated courtship song with a species-specific interpulse interval while they were courted by a mute (wingless) male. Involvement of different song traits in intra- and interspecific mate choice suggests that the song may be affected by both directional and stabilizing selection.