Vibrational directionality in the southern green stink bug, Nezara viridula (L.), is mediated by female song

We tested the hypothesis that male southern green stink bugs, Nezara viridula (L.), use substrate-borne songs to locate females. We recorded the responses of bugs on plants to the vibrations caused by a prerecorded female song and by an artificial sound. The female song caused males to walk, to respond with the calling and courtship songs and to approach the source of the song with characteristic search behaviour at junctions between branches on the plants. At a junction, a searching male stopped, stretched his legs and antennae and compared the vibratory signals on the two branches, with different combinations of legs and antennae. The males then left the junction and approached the source of the vibration. Males located the loudspeaker significantly more frequently in the presence than in the absence of vibratory stimuli on cyperus, Cyperus alternifolius L., and beans, Phaseolus vulgaris L. Vibrational directionality was also elicited by artificial pure tones whose spectral and temporal parameters were similar to those of natural female song. Females showed no reaction to vibratory stimulation and no vibrational directionality. We discuss possible mechanisms underlying vibrational directionality in the light of expected signal changes during transmission through plants. Copyright 1999 The Association for the Study of Animal Behaviour.     

The role of the androconia in the mating behaviour of the European skipper, Thymelicus lineola, and evidence for a male sex pheromone

Abstract. Laboratory experiments were carried out to determine the role and characteristics of male scent scales (androconia), located in patches (stigmata) on the forewings of Thymelicus lineola (Ochsenheimer) (Lepidoptera: Hesperiidae). In behavioural tests, there were 30—40% fewer matings of virgin females by males with the stigmata removed or where females had their antennal sensilla covered with nail polish, when compared to sham-treated controls. These reductions occurred despite a large increase in male courtship activity. No physical contact was observed between male wings and female antennae during mating. A scanning electron microscope study of male wings and female antennae showed that: (1) lysis zones form over time on the androconia and pieces (osmo-phores) distal to these zones break off; (2) while few of these zones are present at emergence they are numerous in-day-old males; (3) during a single episode of courtship and mating approximately two-thirds of the available osmophores break off, yet the commonly observed courtship between males does not appear to result in osmophore release; and (4) osmophores were never observed on the female antennae. Electroantennogram recordings (EAGs) indicated that: (1) female antennae responded strongly to odours from male forewings but not from other parts of either males or females; (2) female antennae responded more strongly to young field-collected males than to newly-emerged or old, field-collected males; (3) female antennal response to male forewings was reduced if the androconia were scraped off, and was eliminated if the stigmata were removed; (4) male antennae gave weak EAG responses to both male and female forewings. We conclude that males release pheromone via the breakage of osmophores during courtship. We propose that the frequently observed refusals by females of courting males are at least partially dependent on the quantity or quality of male pheromone released, which are in turn correlated with the male's age and mating status.     

Female response song in the ephippigerines Steropleurus stali and Platystolus obvius (Orthoptera,Tettigoniidae)

Stridulation by females of Steropleurus stali and Platystolus obvius in response to the calling song of the males was observed and recorded. The response has only been stimulated by the appropriate male song, either directly or from a recording. The structure of the files and the form of stridulation in both sexes is described. The male song of S. stali is remarkable in that only a few teeth on the file are struck in each wing movement. It is also notable that both opening and closing wing strokes contribute more or less equally to the syllable. The female song is similar but distinct. The song of P. obvius male is a single chirp involving nearly all the teeth on the file and with the main emphasis on the closing syllable. The response song of the female is a very brief chirp. These species are only sporadic singers, but when the female responds they are stimulated into greater activity. They thus contrast with reiterative singers like Ephippiger in which there is no female response. The implications of these contrasting behavioural patterns is discussed.     

Removal of both antennae influences the courtship and aggressive behaviors in male crickets

To test whether insect antennae are necessary for eliciting courtship and aggression toward appropriate partners, we antennectomized adult male crickets (Gryllus bimaculatus) and observed their behavior toward other antennectomized males and intact females. At 7 days after removal of both antennae, pairs of antennectomized males were placed together; 80% displayed courtship behavior, generating courtship song by rubbing their forewings together, toward other antennectomized males, and 20% displayed aggressive behavior. Only 45% courted intact females. No intact males courted antennectomized males, and 80% displayed aggressive behavior. All intact males courted females. The results for males with one antenna removed were essentially the same as for intact males. These findings indicate that a high proportion of male crickets with both antennae removed court other males and fail to display male-male aggression, demonstrating that removal of antennae from male crickets induces male-male courtship and that an antenna is necessary for the expression of male-male aggression. Moreover, brain serotonin (5-hydroxytryptamine; 5-HT) levels in male crickets were significantly reduced at 7 days after removal of antennae. The reduction of 5-HT was detected primarily in the central body of the brain. Thus, 5-HT in the central body of the male cricket brain may be involved in the behavioral changes.     

Communication in the courtship of a madagascan hissing cockroach. II. Effects of deantennation

The role of the antennae in courtship was studied by removing the antennae bilaterally from both male and female cockroaches, which were then paired with intact animals. These experimental pairings were compared with each other and with pairings of normal animals. Significant deviation from normal behaviour occurs in both the deantennated and the intact members of experimental pairs. When males are deantennated and paired with intact females the timing of courtship is prolonged and male cockroaches misdirect many of their copulation attempts. Under these conditions the intact female cockroaches perform some behaviours more frequently, in particular mounting and palpation. When deantennated females are paired with intact males, very little courtship ensues. The results suggest that information important to the progress of courtship is provided by both antennal inputs and antennal movements, and that the cockroaches are capable of some behavioural flexibility when deprived of this information.     

Discrimination of conspecific individuals via cuticular pheromones by males of the cricket Gryllus bimaculatus

Cuticular substances on the body surface of crickets serve as pheromones that elicit a variety of different behaviors in male crickets. Antennal contact between males and females resulted in courtship behavior, and that between two males resulted in aggressive displays. As a first step in elucidating how crickets recognize and discriminate individuals, behavioral responses of male individuals to cuticular substances of conspecific males or females were investigated. The behavioral responses of males to antennal or palpal stimulation with an isolated antenna from a male or a female were recorded. To both antennal and palpal stimulation with female antennae, the majority of males responded with courtship behavior; to stimulation with male antennae, males responded with aggressive displays. To gain insight into the chemical nature of the behaviorally relevant components, isolated antennae were washed in either n-hexane, acetone or ethanol before behavior assays. Washed antennae no longer elicited courtship or aggressive responses in males. Next, polypropylene fibers were smeared with substances from the body surface of females and used for antennal stimulation. This experiment showed that the quality and quantity of cuticular substances appear to be highly age-dependent. Significantly more males responded with courtship behavior to cuticular substances from younger females. Isolated males generally showed higher levels of aggression than males reared in groups. Grouped males also were more likely to display courtship behavior towards antennae from younger females, and aggressive behavior towards antennae from older females. These results suggest that male discrimination of mating partners depends on the nature of female cuticular substances.     

Male singing behaviour and female presence in the territory in whitethroats Sylvia communis

Unmated male songbirds usually change their vocal behaviour when females enter their territories. Either the males court the females by changing the rate or pattern with which their normal long-ranging full songs are emitted, or they shift to special displays and long- or short-ranging vocalisations. In this study we quantified how female presence and behaviour affect the singing behaviour of male whitethroats. In the presence of a female the male frequently performed song flights, maybe to locate the female before it was courted, with sequences of diving-song displays. The courtship was interrupted by periods of perch songs. Female dscharp calls and short movements made the males initiate or resume courtship, whereas short horizontal jumps made the males intensify their courtship. Overall, the males changed their dual-function song activity in females' presence by emitting fewer perch songs and more flight songs. The quiet diving songs were only emitted during direct courtship of a female. The song types emitted immediately before, during, and after courtship are all highly variable, thus allowing for a quick assessment of the male's song repertoire. The courtship was also interrupted by periods of male woid calling, a call that is known to have a deterring effect on rival males. Bouts of woid calls were usually followed by song flights, again probably to locate the female that might have moved out of sight, or maybe to locate potential rival intruders. The latter was supported by an increased intrusion rate during female presence. Communicated by P. McGregor     

Female European starling preference and choice for variation in conspecific male song

Data from several field studies support the hypothesis that female European starlings, Sturnus vulgaris, attend to variation among the songs of conspecific males when making mate-choice decisions. However, for a variety of methodological reasons, direct evidence for female preferences based on song in starlings has been lacking. This study presents a novel technique for assaying directly female preference and choice in European starlings by using the presentation of conspecific male song as an operant reinforcer in a controlled environment. Using an apparatus in which the playback of songs from different nestboxes is under the operant control of the subject, we demonstrate how the reinforcing properties of conspecific song can be used to measure female preference and choice. The results of the study suggest three conclusions. First, female starlings prefer naturally ordered conspecific male songs over reversed songs. Second, female starlings display robust preferences for longer compared with shorter male song bouts. Behaviour in the operant apparatus varied directly with male song bout length. Third, preferences based on song bout length are sex specific. Male starlings failed to respond differentially to the same stimuli for which females showed strong preferences. These results suggest that male-male variation in song bout length is important for mate choice among starlings. In addition, we detail the use of a novel behavioural assay for measuring female preferences that can be applied to similar behaviours in other species of songbirds. Copyright 2000 The Association for the Study of Animal Behaviour.     

Courtship song, male agonistic encounters, and female mate choice in the house cricket,Acheta domesticus (Orthoptera: Gryllidae)

Whether female crickets choose among males based on characteristics of the courtship song is uncertain, but in many species, males not producing courtship song do not mate. In the house cricket,Acheta domesticus, we examined whether a female chose or rejected a male based on his size, latency to chirp, latency to produce courtship song, or rate of the high-frequency pulse of courtship song (“court rate”). We confirmed that females mated only with males that produced courtship song, but we found no evidence that the other factors we measured affected a female’s decision to mate. In addition, we investigated whether the outcome of male agonistic encounters affected the subsequent production of courtship song. In one experiment, we observed courtship and mating behavior when a single female was placed with a pair of males following a 10-min interaction period between the two males. Winners of male agonistic encounters had higher mating success. However, winners and losers of agonistic encounters were not different in their likelihood or latency to produce courtship song or in the number of times they were disrupted by the other male in the pair. In a second experiment, we allowed two males to interact for a 10-min period, but following this interaction period, we placed a female with each male separately and observed courtship and mating behavior. The mating success of winners and losers was not different under these circumstances, and we found no differences between winners and losers in any subsequent courtship or mating behavior examined. We conclude that winning agonistic encounters influences a male’s mating success in ways other than his production of courtship song and this effect is lost when winning and losing males are separated and each is given an opportunity to mate.     

蟋蟀对召唤声识别的趋声性定位行为

为了探究蟋蟀种内个体间的声音通讯原理,本研究通过回放利用Cool-edit2000声音采集软件采集的双斑蟋Gryllus bimachlatus召唤声,分别对雌、雄蟋蟀识别召唤声的趋声性定位行为进行了观测研究。实验结果表明:雌、雄双斑蟋对回放的召唤声均有较强的识别反应,但雌蟋蟀的趋声定位性较强,能在较短的时间内积极寻找到声源,路径成"s"型;雄蟋蟀反应相对较弱,路径较长,找到声源时间比雌蟋蟀长。本研究结果揭示召唤声在蟋蟀种内通讯中不仅对个体间的联系有作用,对异性求偶也有重要作用。     

Experimental Tests of the Function and Flexibility of Song Consistency in a Wild Bird

Measures of bird song that capture aspects of motor performance, such as consistency, have become a major focus in understanding sexual selection on song. Despite accumulating evidence that consistency is related to reproductive success in many species, the relative importance of male–male interactions and female–male interactions is still unclear. We studied the function and flexibility of song consistency and song rate in common yellowthroat warblers (Geothlypis trichas). A previous study of this population found that song consistency—measured as the amount of variability within a bout of songs—was positively correlated with the likelihood of siring extrapair young. In this study, we conducted two experiments aimed at testing (1) the role of song consistency and rate in mediating male–male and male–female interactions and (2) whether song effort is flexibly adjusted to changes in social context. In the first experiment, we simulated a male territorial intrusion with song playbacks that varied in consistency and rate; focal males responded aggressively to playbacks, but their response did not differ with playback consistency or rate. In the second experiment, we presented focal males with a taxidermic female mount and female vocalizations; focal males approached the speaker, but continued to sing and did not perform the aggressive rattle vocalization observed during male encounters. Immediately after the simulated female encounter, focal males increased in song consistency. Taken together, our results are most consistent with the hypothesis that song consistency in common yellowthroats is primarily a female‐directed signal that is actively adjusted in response to rapidly changing social conditions.     

Broad Selectivity for Courtship Song in the Cricket Gryllus bimaculatus

Various characteristics of a long‐distance acoustic signal have been shown to vary to different degrees. It has been suggested that female preferences based on stable song parameters are stabilising or weakly directional, and preferences based on variable parameters are strongly directional. We tested this hypothesis based on a short‐distance signal (courtship song) produced by the field cricket, Gryllus bimaculatus. We studied the degree of variability of different courtship song parameters and the behavioural importance of several parameters using synthesised song models in playback experiments. We found that most of the courtship song elements of G. bimaculatus were quite variable (coefficient of variation, CV, in the range of 20–53%). The most variable parameter of the courtship song was the relative amplitude of two elements: high‐amplitude ticks and low‐amplitude pulses. Because songs containing only ticks (of rare occurrence) appeared to be more effective than songs with both ticks and pulses (of frequent occurrence), we consider female preferences to be directional. Alteration of less variable traits, such as the carrier frequency and duration of ticks (CV = 20–25%), had a different effect on female responsiveness. The synthesised songs with different carrier frequencies of ticks were as attractive to females as the positive control (courtship of muted males accompanied by playback of the recorded song). Altering the duration of ticks had a crucial effect on the female response rate, decreasing female responsiveness to the level observed in the negative control (courtship of muted males). Thus, we did not find a strong relationship between the variability of individual song parameters and their potential importance in song recognition and the evaluation of male quality. The partial inconsistency of our results with the data of other authors may be due to different patterns of past and current selection on long‐distance and short‐distance acoustic signals.     

Social context affects testosterone-induced singing and the volume of song control nuclei in male canaries (Serinus canaria)

The contribution of social factors to seasonal plasticity in singing behavior and forebrain nuclei controlling song, and their interplay with gonadal steroid hormones are still poorly understood. In many songbird species, testosterone (T) enhances singing behavior but elevated plasma T concentrations are not absolutely required for singing to occur. Singing is generally produced either to defend a territory or to attract a mate and it is therefore not surprising that singing rate can be influenced by the sex and behavior of the social partner. We investigated, based on two independent experiments, the effect of the presence of a male or female partner on the rate of song produced by male canaries. In the first experiment, song rate was measured in dyads composed of one male and one female (M-F) or two males (M-M). Birds were implanted with T-filled Silastic capsules or with empty capsules as control. The number of complete song bouts produced by all males was recorded during 240 min on week 1, 2, 4, and 8 after implantation. On the day following each recording session, brains from approximately one-fourth of the birds were collected and the volumes of the song control nuclei HVC and RA were measured. T increased the singing rate and volume of HVC and RA but these effects were affected by the social context. Singing rates were higher in the M-M than in the M-F dyads. Also, in the M-M dyads a dominance-subordination relationship soon became established and dominant males sang at higher rates than subordinates in T-treated but not in control pairs. The differences in song production were not reflected in the size of the song control nuclei: HVC was larger in M-F than in M-M males and within the M-M dyads, no difference in HVC or RA size could be detected between dominant and subordinate males. At the individual level, the song rate with was positively correlated with RA and to a lower degree HVC volume, but this relationship was observed only in M-M dyads, specifically in dominant males. A second experiment, carried out with castrated males that were all treated with T and exposed either to another T-treated castrate or to an estradiol-implanted female, confirmed that song rate was higher in the M-M than in the M-F condition and that HVC volume was larger in heterosexual than in same-sex dyads. The effects of T on singing rate and on the volume of the song control nuclei are thus modulated by the social environment, including the presence/absence of a potential mate and dominance status among males.     

Temperature coupling in cricket acoustic communication

Acoustic communication in Gryllus firmus is temperature-coupled: temperature induces parallel changes in male calling song temporal pattern, and in female preference for song. Temperature effects on song production and recognition networks were localized by selectively warming head or thorax or both head and thorax of intact crickets, then eliciting aggression song production (males) or phonotaxis to synthetic calling song (females). Because male song is produced by a thoracic central pattern generator (CPG), and because head ganglia are necessary for female song recognition, measurements of female phonotaxis under such conditions may be used to test the following competing hypotheses about organization of the song recognition network: 1. A set of neurons homologous to the male song CPG exist in the female, and are used as a template that determines preferred values of song temporal parameters for song pattern recognition (the common neural elements hypothesis), and 2. temporal pattern preference is determined entirely within the head ganglia. Neither selective warming of the head nor of the thorax was effective in changing female song preference, but simultaneous warming of head and thorax shifted preference toward a faster song in most preparations, as did warming the whole animal by raising ambient temperature. These results suggest that phonotactic preference for song temporal pattern is plurisegmentally determined in field crickets. Selective warming experiments during aggression song production in males revealed that syllable period is influenced but not completely determined by thoracic temperature; head temperature is irrelevant. The song CPG appears to receive some rate-setting information from outside the thoracic central nervous system.     

The Effect of Male Competition on the Courtship Song of Drosophila melanogaster

The courtship song of Drosophila has been extensively used as a model system for studies of sexual selection and species recognition. Traditionally, the courtship song has been recorded from males placed individually with a female. However, under natural conditions females are exposed to multiple courting males, and the effect of their joint signal on mate recognition by the female is not yet understood. Here, we recorded the courtship behavior of D. melanogaster males singing either individually to a female lpar;1:1) or in the presence of an additional male lpar;2:1). We compared the structure of the male song in the two experimental designs. Our results show that when two males courted a female their songs could overlap each other. Males produced a significantly different signal in the presence of competition; the duration of each song component was significantly shorter and the rate of singing was markedly lower. The present study demonstrates that male competition can dramatically alter the acoustic signal detected by the female.     

The Functions of Song in the Serin

The function of song in the serin Serinus serinus was investigated by measuring variation in singing time and song flights by the male, and nest building by the female during the prelaying and laying period, and by correlating nest building, extra-pair copulation attempts and chasing of the female with male singing time and song flights between pairs. Both singing time and nest building varied in relation to the female fertile period, peaking at day −4. Moreover, nest-building activity correlated with singing time, but not song flights, between pairs. This suggests that song may have a function in stimulating the female to nest build or begin rapid yolk deposition. Pair copulations were not correlated with singing time or song flights either over days relative to laying or between pairs and pairs were not more likely to copulate in a given minute of observation when the male had sung in the previous minute than when he had not. However, extra-pair copulation attempts and chasing of the female showed a tendency to be negatively correlated with song flight but not singing time, between pairs. This suggests that song flight may have a function in discouraging sexual competition from other males.     

Song correlates with social context,testosterone and body condition in male barn swallows

Bird song, like many other male secondary sexual characters, may have evolved as intra- or inter-sexual signals of male phenotypic quality. The hypotheses that song rate and song features reflect androgen levels and body condition, qualities useful in male–male competition, and that they are also influenced by social context, was tested for the first time in the present correlational study. The relationships between song rate and 14 variables describing song structure, respectively, and absolute plasma testosterone levels, body mass, body condition, number of neighbouring males and distances between nest sites in male barn swallows,Hirundo rustica, were analysed. Song rate was not correlated with any of the song features nor with male or social context characteristics. By contrast, a harsh song syllable, the ‘rattle’, was positively related to plasma testosterone levels, and its peak amplitude frequency varied inversely with male body mass and condition. In addition, eight features of song varied according to the social environment of each male. In particular, males sang longer and more varied songs when they had few or no neighbours, whereas males in highly competitive contexts uttered short songs, interrupted them more frequently, and emphasized the rattle. Neighbouring males also sang more similar songs than distant males, and this resulted in matched countersinging. The quality of song output therefore reflects aspects of male competitive potential, and relationships between song structure and social context suggest that some features, such as the rattle, might have originally evolved to serve in male–male interactions; a female preference may have further promoted song evolution leading to complex syllable repertoires.     

Sexual selection, antennae length and the mating advantage of large males in Asellus aquaticus

In crustacean species with precopulatory mate-guarding, sexual size dimorphism has most often been regarded as the consequence of a large male advantage in contest competition for access to females. However, large body size in males may also be favoured indirectly through scramble competition. This might partly be the case if the actual target of selection is a morphological character, closely correlated with body size, involved in the detection of receptive females. We studied sexual selection on body size and antennae length in natural populations of Asellus aquaticus, an isopod species with precopulatory mate guarding. In this species, males are larger than females and male pairing success is positively related to body size. However, males also have longer antennae, relative to body size, than females, suggesting that this character may also be favoured by sexual selection. We used multivariate analysis of selection to assess the relative influences of body size and antennae length in five different populations in the field. Selection gradients indicated that, overall, body size was a better predictor of male pairing success than antennae length, although some variation was observed between sites. We then manipulated male antennae length in a series of experiments conducted in the lab, and compared the pairing ability of males with short or long antennae. Males with short antennae were less likely to detect, orient to, and to pair with a receptive female compared with males with long antennae. We discuss the implications of our results for studies of male body size and sexual dimorphism in relation to sexual selection in crustaceans.     

雄性稻绿蝽对雌性鸣唱反应的物种特异性

雌性稻绿蝽的鸣唱开始了在基质中产生的通讯并引起雄性不同的特定反应。在两种自然情况下 ,我们检验了雄性稻绿蝽对N viridula ,Thyantapallidovirens和Thyantacustatoraccerra个体鸣唱刺激反应的物种特异性水平 ,并对反应强度和同种及异种刺激性鸣唱的时间特性进行了相关分析 ,证明雄性求偶鸣唱的发送和震动源的定位是最具物种特异性的反应。然而 ,即便是在这个水平上 ,雄性稻绿蝽不能将同种雌性个体的鸣唱与T .custatoraccera的第二个雄性个体的鸣唱区分开来 ,后者与前者有相似的脉冲持续时间和重复时间值。本文也讨论了涉及交配行为鸣唱期的有关信号的物种特定性的概念     

The song structure and seasonal patterns of vocal behavior of male and female bellbirds (Anthornis melanura)

The bellbird (Anthornis melanura) is a honeyeater endemic to New Zealand, which uses song to defend breeding territories and/or food resources year round. Both sexes sing and the song structure and singing behavior have not yet been quantified. The number of song types, spectral structure, repertoire size, and singing behavior of male and female bellbirds was investigated for a large island population. Song types differed between the sexes with males singing a number of structurally distinct song types and females producing song types that overlapped in structure. Singing behavior also differed between the sexes; males often sung long series of songs while females sung each song at relatively long and variable intervals. Singing by both sexes occurred year round but the frequency of male and female singing bouts showed contrasting seasonal patterns. The frequency of female singing bouts increased as the breeding season progressed, whereas male singing bouts decreased. In contrast to almost all studied passerines, female bellbirds exhibited significant singing behavior and sung songs of complex structure and variety that parallel male song. These results provide a quantitative foundation for further research of song in bellbirds and in particular the function of female vocal behavior.