Sexual Interference in the Sword-tailed Newt,Cynops ensicauda popei (Amphibia: Salamandridae)

This paper describes competitive interaction between males of the salamandrid Cynops ensicauda popei. The sexual behaviour of the male is influenced by the presence of a second, rival, male. Competition for access to the female and other male interactions continuously interrupt ongoing courtships. Spermatophore pick-up success is lower than in encounters involving single pairs. During triad encounters, fewer spermatophores were deposited than in dyad encounters, due to interference during the creep stage of courtship. Two basic forms of male sexual interference were distinguished: ‘lure away’ during the creeping stage, from a position that is different from the direction of creep; and ‘female mimicry’, during which the male presses his snout alternately against the courting male's tail and the female's snout. In both forms, a rival male may shove one of the courting individuals away. The repertoire of sexual behaviour patterns of Cynops ensicauda popei appears to be less complex and varied than that of most Triturus species. The courtship of Cynops places less emphasis on display behaviour with tail and body, and a stronger emphasis on the creeping stage, where the male carefully leads the responsive female over a series of spermatophores, but during which rival males may interfere in a variety of ways.     

Me against who? Male guppies adjust mating behaviour according to their rival’s presence and attractiveness

Sexual selection theory suggests that males need to constantly reappraise their mating decisions to take account of the presence and the phenotypes of their rivals. Here we examine this expectation by asking: (i) If the presence of a rival influences male mating behaviour; (ii) How important is the attractiveness of the rival (absolute attractiveness) in shaping male behaviour; and (iii) How does a male's attractiveness in comparison to his rival (relative attractiveness) influence a male's mating decisions. Using the Trinidadian guppy, a species in which female mate choice (based on males’ attractive traits) plays an important role in male mating outcomes, we recorded the frequency of courtship displays and unsolicited attempts by focal males. First, we quantified focal male mating behaviour with and without a rival. Since the probability of a successful mating is, on average, halved by the presence of a rival, we predicted that under competition the focal male would invest more in less costly mating tactic—unsolicited attempts. Second, we examined how the rival's standard length and area of orange coloration mediated focal male mating behaviour. We found that rival presence influenced how focal males responded to females in terms of both mating tactics. However, the rival attractiveness elicited changes only in male courtship display. Focal males increased courtship display rate if his rival was small or if possessed large amounts of orange, regardless of considering rival absolute or relative attractiveness. Our results show that males invest in the costlier mating tactic when there is no rival or in the presence of a smaller rival. Interestingly, they make a similar investment in the presence of an attractive orange rival. Overall, this study highlights the importance of fine‐grained male decisions in mating encounters and shows that mating tactics are differentially shaped by multiple competition risk cues.     

Mate assessment in a cockroach,Nauphoeta cinerea

The behavioural effects of assessment of male dominance status on male and female courtship were investigated in the cockroach, Nauphoeta cinerea. Dominance hierarchies were established in laboratory groups of male N. cinerea; virgin females were then given the opportunity to (1) male with a subordinate male in the presence of dominant male odours; (2) mate with a dominant male in the presence of subordinate male odours; (3) mate with a male in the presence of another male's odour, both males lacking status; (4) mate when only a single male was present and no other male's odour was presented. The presence of the dominant male resulted in a significant delay in the approach of a female to a subordinate male and in the response of a female to a courtship display by the subordinate male. Males that lacked status were significantly slower to initiate courtship behaviours. Copulatory time was significantly shorter for subordinate males and males without status. Information concerning the dominance status of neighbouring males is used in assessment of appropriate mating behaviour by males and as a possible criterion in female choice.     

Temporal patterning of courtship behaviour in some parasitic Hymenoptera,with special reference to Melittobia acasta

In many parasitic hymenoptera copulation is preceded by elaborate courtship displays which include species-specific characteristics. Other features, shared by related species, may be used for defining higher taxa. The male's repertoire consists of movements involving the wings, legs, antennae, and mouthparts. These movements are performed continuously, or intermittently, depending on the species involved. The elements of a repertoire are repeated over and over again until the female indicates her readiness to copulate. Temporal patterning of various displays, and the timing of the female response are described. In Melittobia acasta (Walker) (Eulophidae) the male display is composed not only of repeating elements, but also includes new elements, introduced along the way; the display progresses towards a climactic finale. The timing of the female's copulation signal is accurately predictable. The morphology of Melittobia males is discussed in relation to this behaviour. Courtship of a related species, M.chalybii, is compared to the courtship of M.acasta.     

Male moth songs tempt females to accept mating: the role of acoustic and pheromonal communication in the reproductive behaviour of Aphomia sociella

Background

Members of the subfamily Galleriinae have adapted to different selective environmental pressures by devising a unique mating process. Galleriinae males initiate mating by attracting females with either chemical or acoustic signals (or a combination of both modalities). Six compounds considered candidates for the sex pheromone have recently been identified in the wing gland extracts of Aphomia sociella males. Prior to the present study, acoustic communication had not been investigated. Signals mediating female attraction were likewise unknown.

Methodology/Principal Findings

Observations of A. sociella mating behaviour and recordings of male acoustic signals confirmed that males initiate the mating process. During calling behaviour (stationary wing fanning and pheromone release), males disperse pheromone from their wing glands. When a female approaches, males cease calling and begin to produce ultrasonic songs as part of the courtship behaviour. Replaying of recorded courting songs to virgin females and a comparison of the mating efficiency of intact males with males lacking tegullae proved that male ultrasonic signals stimulate females to accept mating. Greenhouse experiments with isolated pheromone glands confirmed that the male sex pheromone mediates long-range female attraction.

Conclusion/Significance

Female attraction in A. sociella is chemically mediated, but ultrasonic communication is also employed during courtship. Male ultrasonic songs stimulate female sexual display and significantly affect mating efficiency. Considerable inter-individual differences in song structure exist. These could play a role in female mate selection provided that the female''s ear is able to discern them. The A. sociella mating strategy described above is unique within the subfamily Galleriinae.     

Choosing a mate in a high predation environment: Female preference in the fiddler crab Uca terpsichores

The interplay between a receiver's sensory system and a sender's courtship signals is fundamental to the operation of sexual selection. Male courtship signals that match a female receiver's preexisting perceptual biases can be favored yet the message they communicate is not always clear. Do they simply beacon the male's location or also indicate his quality? We explored this question in a species of fiddler crab Uca terpsichores that courts under elevated predation risk and that mates and breeds underground in the safety of males' burrows. Sexually receptive females leave their own burrows and are thereby exposed to avian predators as they sequentially approach several courting males before they choose one. Males court by waving their single greatly enlarge claw and sometimes by building a sand hood next to their burrow entrance. Hoods are attractive because they elicit a risk‐reducing orientation behavior in females, and it has been suggested that claw waving may also serve primarily to orient the female to the male. If the wave communicates male quality, then females should discriminate mates on the basis of variation in elements of the wave, as has been shown for other fiddler crabs. Alternatively, variation in elements of the claw waving display may have little effect on the display's utility as a beacon of the location of the male and his burrow. We filmed courting males and females under natural conditions as females responded to claw waving and chose mates. Analysis of the fine‐scale courtship elements between the males that females rejected and those they chose revealed no differences. When predation risk during courtship is high, males' courtship displays may serve primarily to guide females to safe mating and breeding sites and not as indicators of male quality apart from their roles as beacons.     

Long‐distance signals influence assessment of close range mating displays in the field cricket,Gryllus integer

Male sexual displays often include components detected across long distances, and those perceived only at close range. Understanding what information females gain from each component of a complex display and how they use these signals to make decisions are questions of major interest in sexual selection research. We evaluated content‐based hypotheses (‘redundant signals’ and ‘multiple messages’) for the courtship displays of field crickets (Gryllus integer) by measuring female responses to males' long‐distance calling song (calls) and close‐range chemical cues. Females' responses to a male's calls and chemical cues were uncorrelated, supporting the ‘multiple messages’ hypothesis. We also tested the ‘inter‐signal interaction’ hypothesis by investigating how long‐distance calls influence evaluation of close‐range courtship. The relationship between long‐ and close‐range signals was complex and conditional: females accepted close‐range courtship more quickly after exposure to attractive calling song than they did after exposure to either unattractive calling song or silence, and unattractive calls were no more or less effective than silence. This inter‐signal interaction could affect our understanding of mate choice in species with multiple mating signals because it implies that females may save time and energy by not assessing the close‐range signals of attractive long‐distance signalers. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 856–865.     

A courtship advantage for small males in Drosophila subobscura

Large male Drosophila subobscura carry bigger drops of regurgitated food during courtship and have greater courtship success with starved females than do small males. However, if males are prevented from producing a drop, the small males have greater courtship success than the large males, suggesting that they perform some other aspect of courtship better than large males. In the present study small males were better than large ones at tracking the female during the courtship dance. Although males of different sizes ran at the same top speed during the dance, the larger males lagged further behind the female presumably because they take longer to accelerate to or decelerate from any given speed. A male's walking ability will also depend on other factors such as his ‘athletic ability’ and the amount of food stored in his crop and body tissues. The possible relationships between athletic and food gathering ability and fertility in wild males are discussed.     

Sizing‐up the Competition: Factors Modulating Male Display Behavior During Mate Competition

When competing for mates, males of many species use cues from their rivals to evaluate their chances of success. Signaling behavior is a vital component of male–male contests and courtship, and may inform males of a rival's quality or intentions. We used eastern fence lizards (Sceloporus undulatus) to investigate how the time a male spent signaling during mate competition is influenced by his quality, his rival's quality relative to his own, and the value of a contested female. Furthermore, we examined how a male's behavioral response to a competitor's signals would be mediated by his relative quality. We simulated natural encounters by allowing two males to compete over a single female in the laboratory. We measured the time males spent performing two types of displays (pushups and shudders) and categorized male behavioral responses to rival pushup and shudder displays. Time spent signaling was not related to a male's absolute quality (body and head size, condition, and badge sizes), or his quality relative to that of his rival, although males did spend more time performing pushups when competing over females in better condition. Male behavior was also influenced by his rival's signals, such that males of relatively lower quality than their opponents were more likely to aggressively respond to rival pushups and shudders. We discuss these results with respect to the evolution and function of signaling behavior in courtship and male–male contests.     

The Influence of Sequential Male Courtship Behaviors on Courtship Success and Duration in a Terrestrial Salamander,Plethodon shermani

Most organisms use multiple cues across many modalities to assess potential mates. Salamanders in the genus Plethodon have an elaborate courtship display, yet previous studies primarily have concentrated on the influence of olfactory cues on courtship success. In this study, we tested whether two different cues (one chemical and one visual) affected courtship success and duration in the red‐legged salamander, Plethodon shermani. By staging and observing over 180 courtship trials, we found that ‘foot‐dancing’, a male visual cue performed in the earliest stages of courtship, significantly increased the likelihood that a male and female would progress to subsequent stages of courtship and, thus, the likelihood of insemination. In contrast, delivery of biologically relevant levels of a non‐volatile pheromone (produced in a large gland on the male's chin) during courtship trials did not increase overall insemination rate success, but did significantly reduce the duration of one of the later stages of courtship, tail‐straddling walk. Thus, we propose that early use of visual cues in Plethodon courtship, may (1) increase the detectability of the male message by increasing the range at which the male can be perceived by the female and (2) indicate the context of the male's approach and subsequent behaviors. In short, this study draws attention to the need to examine behavioral traits affecting courtship success at multiple stages and across several sensory modalities.     

Courtship feeding in Drosophila subobscura. I. The nutritional significance of courtship feeding

By feeding male Drosophila subobscura with stained yeast before courtship it was shown that the males transfer regurgitated crop contents to females during courtship. The female takes the drop of food with her proboscis directly from the male's extended proboscis and the male then attempts to copulate. The food passes into the female crop or ventriculus and females that take the drop have higher fecundity on a low-nutrient medium than those females denied access to the drop. ‘Starved’ females take the drop of food from the male more frequently than well-fed females and a comparison of crop sizes revealed that flies collected from the wild resemble the starved laboratory groups. Similar courtship feeding behaviours are described for other members of the obscura species group. Within the willistoni species group, male D. nebulosa deposit an anal drop containing gut contents on the substrate in front of the female during courtship and females consume this drop. A review of the literature suggests that various forms of courtship feeding may be widespread within the genus but that the extent of feeding by males of different species may vary.     

Mate searching in Ennya maculicornis (Membracidae: Polyglyptini) initiated by females: behavioural and acoustic descriptions

1. In treehoppers in which courtship has been studied, males initiate the search for females by periodically emitting a vibrational signal. The responses by the female are used by males as a beacon and give rise to a duet. 2. Courtship and mating of the treehopper Ennya maculicornis were characterised through the simultaneous recording of vibrational signals and the behaviour of males and females in an arena. 3. In E. maculicornis, female initiated mate searching. Females produced two types of signals during the this process: (i) a signal that preceded the approach by the male and (ii) a signal that preceded mating. Males emitted two signals associated with two stereotyped body movements: (i) a signal produced as a response to the first signal emitted by the female, involving a change in the male's locomotory mode and the approach to the female, and (ii) a signal produced after finding and holding on to the female, involving simultaneous abdomen raising and wing fluttering. These signals were repeated several times before the female emitted the second signal. The four signalling patterns were observed in all recordings in which mating was observed. When any of the signals was missing, mating did not occur. 4. Female‐biased sex ratios in E. maculicornis, along with iteroparity, are suggested to explain the initiation of mate searching behaviour by females. A comparison of data with that from other treehoppers indicates that vibrational signals and their associated behaviour are more diverse among treehoppers than has been appreciated previously.     

Behavioural allometry and interdemic variation in sexual behaviour of the sailfin molly,Poecilia latipinna (Pisces: Poeciliidae)

Sailfin mollies, Poecilia latipinna, exhibit remarkable levels of intraspecific variation in reproductive behaviour. Larger males exhibit higher rates of courtship and lowered rates of gonoporal nibbling and gonopodial thrusting (forced copulation attempts). Larger males have relatively longer and higher dorsal fins than smaller males. The dorsal fin is a prominent component of the courtship display. Variation in fin measurements, behaviour patterns, and body size of mature males is continuous, and fin shape and behaviour patterns are allometrically related to body size. The allometric pattern is displayed by individual traits as well as by the morphological or behavioural traits in ensemble. Eight populations of mollies from markedly distinct habitats exhibited similar consistent levels of intrademic variation in the size of mature males. Detailed studies on three populations showed that dorsal fin shape could be described by the same regression relationship in all populations, and indicted that a male's shape was determined by his absolute body size. By contrast, there was some variation among populations in the relation of behaviour patterns to male body size. The pattern of this interdemic variation indicated that a male's behaviour patterns were influenced by his relative size in a population. Successful inseminations following forced copulations were rare. The average size of successful males was smaller than the average size of unsuccessful males in all three populations. These results indicated that successful insemination through forced copulation was, like behaviour patterns generally, more a function of the relative size of the male, than his absolute size.     

Consistency of females’ stridulatory behaviour during inter‐sexual interactions in spiders

In a sexual context, it is expected that females base their choice of mate on the behaviours that males perform during courtship, as such behaviours are associated with the male's mate quality. Stridulation is one form of female communication in arthropods, for example, spiders. In spiders, stridulation during sexual interactions is relatively common in some groups but mainly restricted to males. In the pholcid spider Holocnemus pluchei (Pholcidae), both sexes have stridulatory organs. The aims of the present work were to: (a) determine possible differences in the frequency of occurrence of stridulation between females during inter‐sexual interactions, (b) establish female consistency in stridulation along repeated interactions and (c) analyse if female stridulation is associated with certain male behaviours during pre‐copulatory courtship and with male size. Female H. pluchei showed highly repeatable differences in their frequency of stridulation across consecutive encounters with males (ICC = 0.64). However, only a modest level of repeatability was detected in total time females spent stridulating across trials (ICC = 0.19). Females’ mean stridulatory behaviour did not change across ten consecutive trials spread across 20 days, and their behaviour was apparently unaffected by male persistence of copulatory attempted and/or size. These results imply that the frequency of female stridulatory behaviour is a trait that is highly characteristic of each individual. Finally, our work opens the door to determine whether behavioural consistency manifests in other ecological contexts and their functional implications.     

The Elaborate Postural Display of Courting <Emphasis Type="Italic">Drosophila persimilis</Emphasis> Flies Produces Substrate-Borne Vibratory Signals

Sexual selection has led to the evolution of extraordinary and elaborate male courtship behaviors across taxa, including mammals and birds, as well as some species of flies. Drosophila persimilis flies perform complex courtship behaviors found in most Drosophila species, which consist of visual, air-borne, gustatory and olfactory cues. In addition, Drosophila persimilis courting males also perform an elaborate postural display that is not found in most other Drosophila species. This postural display includes an upwards contortion of their abdomen, specialized movements of the head and forelegs, raising both wings into a “wing-posture” and, most remarkably, the males proffer the female a regurgitated droplet. Here, we use high-resolution imaging, laser vibrometry and air-borne acoustic recordings to analyse this postural display to ask which signals may promote copulation. Surprisingly, we find that no air-borne signals are generated during the display. We show, however, that the abdomen tremulates to generate substrate-borne vibratory signals, which correlate with the female’s immobility before she feeds onto the droplet and accepts copulation.     

Male–male interactions and male mating success in the leafhopper Aphrodes makarovi

In mating systems based on substrate‐borne vibrations, sexual communication often involves a reciprocal exchange of species‐ and sex‐specific vibrational signals and male is searching for a stationary female. In the leafhopper Aphrodes makarovi, female reply is essential for successful location of the female and its variable duration directly affects male's costs associated with signalling and searching. We studied male and female behaviour in a trio situation (two males and one female), and our results show that male–male competition had important effects on male mating success. Females replied equally to advertisement calls emitted by the winning and losing males and mated with the first male that located them, regardless of his investment in calling effort. Males eavesdropped to male–female duet maintained by the rival, and the winners were better at exploiting female replies to the rival's advertisement calls by silently approaching the female. To interfere with the ongoing male–female duet, males also emitted masking signals overlapping the latter part of the female reply. More overlapped female replies were registered in response to the losers and masking signals most likely delay the rival in reaching the female. Our study shows that a comprehensive understanding of male mating success and female preferences in vibrational duetting systems requires also investigations in more complex settings that more realistically represent the situation in nature.     

Male Competition in a Wandering Spider (Cupiennius getazi,Ctenidae)

We describe male-male competition in a wandering spider living on plants (Cupiennius getazi, Ctenidae) and discuss it within the general context of the mating system. 1. Males produce vibratory courtship signals (duration about 20 s) and competition signals (2 s). Upon exposure to female silk, males produce almost exclusively courtship signals (98%) if alone or in the presence of a female. In the presence of a rival alone, an average of 25% of a male's vibratory signals are courtship signals and 75% competition signals. In the presence of both a rival and a female, an average of 50% are courtship and 50% competition signals. Females respond to both male courtship and/or competition signals with vibratory courtship whereas males react by vibratory competition. The intensity of the reaction of both males and females is independent of the signal type. 2. Males displaying vibratory signals move slowly over the plant and repel attacks from rivals and females with extended front legs. Pairs of males interact in three ways. (i) Both males produce vibratory signals; one of them leaves the plant (53% of 90 trials). (ii) Both males vibrate, approach and touch (20%) or pounce on each other (20%). (iii) A male approaches the signalling opponent without producing vibrations and attacks him (7%). This is a conditional vibrocryptic tactic. The presence of a female incites male competition. Males do not interact with the female but approach each other (in 24% of the 26 trials “vibrocryptically”) and escalate more often (88%) and more quickly to overt fight than in the absence of a female. The male remaining on the plant approaches the female. 3. Male-male fights are ritualized. During 64 bodily contacts no male was injured. Males exposed to female silk and males using the vibrocryptic tactic were more often the winners of an interaction than males not exposed to female silk and than males vibrating while approaching their rival. The outcome of fights is not correlated with age, leg length, body weight and rate of signalling when no female is present. In contrast, body weight and leg length determine the outcome when a responding female is present, the larger male being the winner. 4. Intrasexual and intersexual interactions suggest that both male competition and female choice mechanisms may regulate sexual selection in this species.     

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.     

Partitioning the Components of Sexual Selection: Attractiveness and Agonistic Behaviour in Male Wax Moths,Achroia grisella (Lepidoptera: Pyralidae)

Two components of sexual selection in the lesser wax moth, Achroia grisella, are clearly defined: females choose males based on characters of their ultrasonic advertisement signals, and males display agonistic behaviour patterns in contests over signalling stations. We conducted a series of laboratory trials to determine whether successes in these two sexual selection arenas were related. Our trials showed that winners in contests over signalling stations were characterized by earlier initiation of both signalling and aggression. These characteristics may indicate higher levels of ‘motivation,’ but it is unclear whether this level is a fixed trait. There was no relationship, however, between any measure of a male's attractiveness to females and his success in winning competition trials. Thus, inter- and intra-sexual selection may be acting on different, uncorrelated traits in A. grisella.     

Mechanism of mate detection in parasitoid wasps: sound and vibratory cues change with the developmental progress of future mates inside host pupal cases

Insects including parasitoid wasps use acoustic and vibratory signals in the context of sexual communication, mate recognition, courtship and mating. Males of the parasitoid wasp Pimpla disparis Viereck (Hymenoptera: Ichneumonidae) detect insect host pupae parasitized by a conspecific female, learn their location, visit them repeatedly and remain on or near them when the prospective mate nears emergence. In the present study, the acoustic and vibratory cues that males exploit to detect the presence and track the developmental progress of a future mate inside a host pupal case are investigated. Responses are acquired from developing parasitoids (DePa) by airborne sound and laser Doppler vibrometer recordings, after gently stimulating each of 20 wax moth host pupae with a paintbrush on days 1–23 post parasitism. Sound and vibratory cues produced by DePa are detectable from day 7 onward and relate mostly to spinning movements. Parameters of sound and vibratory cues (amplitude, dominant frequency, upper limit of frequency band) change significantly over time and thus could ‘inform’ a visiting adult male about the stage of development of DePa. Adult males antennating a parasitized pupa and flying around it also induce vibrations, which in turn may inform DePa about the presence of a male. There is no experimental evidence for true signalling and rapid information exchange between DePa and adult males. Delaying reply signals may help DePa avoid attacks by illicit receivers of such signals, including female (hyper)parasitoids and invertebrate predators.