Male-female Duets Research Articles

Leafhopper males compensate for unclear directional cues in vibration-mediated mate localization

Ambient noise and transmission properties of the substrate pose challenges in vibrational signal-mediated mating behavior of arthropods, because vibrational signal production is energetically demanding. We explored implications of these challenges in the leafhopper Aphrodes makarovi (Insecta: Hemiptera: Cicadellidae) by exposing males to various kinds of vibrational noise on a natural substrate and challenging them to find the source of the female playback. Contrary to expectations, males exposed to noise were at least as efficient as control males on account of similar searching success with less signaling effort, while playing back male–female duets allowed the males to switch to satellite behavior and locate the target without signaling, as expected. We found altered mitochondrial structure in males with high signaling effort that likely indicate early damaging processes at the cellular level in tymbal muscle, but no relation between biochemical markers of oxidative stress and signaling effort. Analysis of signal transmission revealed ambiguous amplitude gradients, which might explain relatively low searching success, but it also indicates the existence of behavioral adaptations to complex vibrational environments. We conclude that the observed searching tactic, emphasizing speed rather than thorough evaluation of directional cues, may compensate for unclear stimuli when the target is near.

Group chorusing as an intragroup signal in the greater ani, a communally breeding bird

AbstractGroup living often requires maintaining dynamic and varied relationships with fellow group members, while simultaneously monitoring and interacting with external competitors. Group members in many social species vocalize together to produce duets or choruses—coordinated, often conspicuous vocal displays—that may play a role in these interactions. Compared with male–female duets, however, relatively little research exists on the function and adaptive significance of group choruses, which involve three or more individuals. Here we investigate chorusing behavior in the greater ani (Crotophaga major), a communally breeding cuckoo that nests in stable social groups of four to eight unrelated individuals. Groups may remain together for several years on the same nesting territory, and groups occasionally destroy each other's clutches in conflicts over high‐quality territories. We asked whether the raucous, highly stereotyped choruses performed by ani groups are primarily used for intra‐ or intergroup communication, and whether they contain information about the identity of the social group and the number of birds vocalizing. Behavioral observations and acoustic recordings from three breeding seasons revealed that choruses typically occurred during social interactions within the group (78% of choruses) or in response to a predator or extra‐group individual (17%) and only rarely in intergroup interactions (4%). Consistent with this finding, choruses did not reliably reflect the number of birds vocalizing, and we found only limited evidence for group‐specific acoustic signatures (driven by a single group whose choruses were highly distinct). These results suggest that group choruses play an important role in intra‐group signaling, potentially in contexts such as group formation, reinforcement of social bonds within the group, and/or collective decision‐making, and they motivate new research questions about the role of collective signaling in social evolution.

Loss of complex female song but not duetting in the ancestors of Carolina wrens

AbstractFemale singing and coordinated male–female duetting are often but not always found in the same species. Both behaviors are more common in tropical than temperate songbirds, but few studies have differentiated between the factors selecting for each. Here we investigate the evolution of female vocal complexity and male–female vocal coordination in Carolina wrens (Thryothorus ludovicianus), one of the few non‐tropical members of a songbird family (Troglodytidae) that is well known for producing coordinated male–female duets. Female Carolina wrens are not known to sing; rather, they produce relatively simple, sex‐specific chatters, often during territorial encounters. We analyzed field recordings to show that females coordinate these chatters with male songs at rates similar to those observed in some tropical duetting wren species. We then used phylogenetic comparative methods to show that the evolutionary ancestors of Carolina wrens had female songs that were more acoustically complex than the vocalizations of current females, suggesting past selection against female vocal complexity. Levels of vocal coordination with males, in contrast, have changed relatively little from those of tropical ancestors. Our results suggest that these two aspects of female behavior, acoustic complexity and vocal coordination with males, have evolved independently and have different functions in communication.

Temperature‐related breakdowns in the coordination of mating in Enchenopa binotata treehoppers (Hemiptera: Membracidae)

AbstractTemperature influences the expression of a wide range of behavioral traits in ectotherms, including many involved in the initiation of pair formation and mating. Although opportunities to mate are thought to be greatest when male and female activity overlap, sex‐specific behaviors and physiology could result in mismatched thermal optima for male and female courtship. Here, we investigate how conflicts in the thermal sensitivity of male and female courtship activity affect patterns of mating across temperatures in Enchenopa binotata treehoppers (Hemiptera: Membracidae). These plant‐feeding insects coordinate mating with plant‐borne vibrational signals exchanged in male–female duets prior to pair formation. We manipulated temperature across an ecologically relevant range (18–36ºC) and tested the likelihood of individual male and female E. binotata to engage in courtship activity using vibrational playbacks. We then staged male–female mating interactions across the same temperature range and quantified the thermal sensitivity of mating‐related behaviors across stages of mating. Specifically, we measured the timing of duetting, the likelihood for key pre‐copulatory behaviors to occur, whether the pair mated, and copulation duration. We found sex‐specific thermal sensitivity in courtship activity: Males showed a clear peak of activity at intermediate temperatures (27–30ºC), while females showed highest activity at the hotter thermal extreme. Mating rates, courtship duets, and copulatory attempts were less likely to occur at thermal extremes. Also, duetting occurred earlier and copulation was shortest at higher temperatures. Overall, our data suggest that sexes differ in how temperature affects mating‐related activity and some processes involved in mate coordination may be more sensitive than others across variable thermal environments.

Some negative contents portrayed in English song lyrics

Some song lyrics may have been banned or rescheduled for their radio and television broadcasts. Those song lyrics were claimed to propagandize negative contents. Recently West Java Broadcasting Commission has regulated the broadcast of 17 western songs for the prejudice of negative contents. Based on semantic analysis of those song lyrics, the authors finally found out that they qualitatively describe lust, profanity, drug and alcohol abuse, etc. through periphrasis, simile, litotes, meiosis, and other speech figures. Clauses were selected to deliver the figures of speech of the lyrics sung by mostly male singers and the male-female duets in pop and r and b music genres.

Patterns of Thermal Sensitivity and Sex-Specificity of Courtship Behavior Differs Between Two Sympatric Species of Enchenopa Treehopper

Predicting how insects will react to future thermal conditions requires understanding how temperature currently affects insect behavior, from performance traits to those involved in mating and reproduction. Many reproductive behaviors are thermally-sensitive, but little is known how temperature affects the behaviors used to find mates and coordinate mating. Here, we investigate how temperature influences courtship activity in two sympatric species of Enchenopa treehoppers (Hemiptera: Membracidae). Enchenopa use substrate-borne vibrational signals exchanged in male-female duets to facilitate pair formation prior to mating. In a controlled laboratory setting, we assessed the likelihood of males and females to produce courtship signals across a range of ecologically relevant temperatures. We found that changes in courtship activity across temperatures differed between the two species. We also found sex differences within species: in one species males were more likely to signal at higher temperatures, while in the other species females were more likely to signal at higher temperatures. Our results suggest that sex-specific responses to temperature may constrain mating to narrower ranges of temperatures. Furthermore, sympatric species may respond differently to changes in thermal variation despite sharing similar climactic history.

The function of collective signalling in a cuckoo

Collective signalling occurs in diverse animal groups. A particularly well-studied form of this sophisticated communication behaviour is vocal duetting in birds, in which members of a mated pair coordinate their songs on short temporal scales. Many hypotheses have been proposed to explain the function of bird duets, but the experimental evidence for them is still somewhat conflicting. Studies on songbirds often provide support for the joint resource defence or mate-guarding hypotheses. We investigated these hypotheses for a nesting cuckoo, the white-browed coucal, Centropus superciliosus, by presenting territorial pairs with four types of playback treatment: male–female duets, female solos, male solos, and a heterospecific control. The observed birds reacted aggressively to the conspecific playback by approaching the playback loudspeaker and singing. Pairs responded with duets more often to duet playbacks than to playbacks of female and male solo song. Also, neither sex treated simulated unmated intruders (solo playback) as more threatening than mated intruders (duet playback). Taken together, these findings argue against the mate-guarding hypothesis and instead suggest that duetting in white-browed coucals functions primarily in joint territory defence. In almost all cases, males were the first sex to sing in response to playbacks and, overall, they sang more than females. This suggests that males take a primary role in territorial defence. However, females also responded strongly, especially to the simulation of mated or unmated female intruders, hinting at a sex-specific division of labour in territorial defence.

Behavioral Ecology of Elliot’s Laughingthrush (Trochalopteron (Garrulax) elliotii, Timaliidae, Aves): 2. Vocal Repertoire

Our work is the first study on the vocal repertoire of one of the babbler species, Elliot’s laughingthrush. Field studies were carried out in Hupingshan Nature Reserve, Hunan Province, China. There are three types of signals in the repertoire: songs, calls (chattering), and duets. Songs and calls are used by both males and females. The song consists of a quiet introduction (short note) and a louder main part (two or three tonal notes). There are up to four song variants in the repertoire of a given pair. All songs can be classified into three types. Types I and II represent songs with the main part consisting of three notes, while type III consists of two notes. Types I and II differ from each other in certain features of the frequency modulation shape of the first two notes. All song types can be used during the spontaneous vocalization of a single bird. However, their usage in other contexts differs. Songs of types I and II are more often uttered during vocal interactions of neighbor males. Songs of type III appear to be characteristic of male–female duets. Chattering (calls) is a continuous series of broadband notes. There are several (two to five) note variants in each series. Chattering can be used both during a male–female interaction and as an alarm call. We found an inverse correlation between (1) the duration of pauses between notes, and (2) the number of note variants (“repertoire size”) in a series. Both parameters probably reflect the internal state of an individual at a given moment.

Males adjust their signalling behaviour according to experience of male signals and male-female signal duets.

Sexual signals are conspicuous sources of information about neighbouring competitors, and species in which males and females signal during pair formation provide various sources of public information to which individuals can adjust their behaviour. We performed two experiments with a duetting vibrational insect, Enchenopa binotata treehoppers (Hemiptera: Membracidae), to ask whether males adjust their signalling behaviour according to (1a) their own experience of competitors' signals, (1b) how females adjust their mate preferences on the basis of their experience of male signals (described in prior work), and/or (2) their own experience of female response signals to competitors' signals. We presented males with synthetic male signals of different frequencies and combinations thereof for 2 weeks. We recorded males a day after their last signal exposure, finding that (1a) male signal rate increased in response to experience of attractive competitors, but that (1b) male signal frequency did not shift in a manner consistent with how females adjust their mate preferences in those experience treatments. Second, we presented males with different male-female duets for 2 weeks, finding that (2) male signal length increased from experience of female duets with attractive competitors. Males thus make two types of adjustment according to two sources of public information: one provided by experience of male signals and another by experience of female responses to male signals. Signalling plasticity can generate feedback loops between the adjustments that males and females make, and we discuss the potential consequences of such feedback loops for the evolution of communication systems.

Playback experiments for Thryothorus ludovicianus in urban backyard experiments

Acoustic playback experiments were performed from June 2014 to April 2015 for Thryothorus ludovicianus (Carolina Wren) in a backyard environment in Austin, Texas. Acoustic recordings were made for pre-playback, playback, and post-playback periods for multiple song types. The songs were obtained from recordings made in the backyard and surrounding neighborhood. Recordings of both the playback and acoustic responses of the bird subjects are made in coincidence with visual observations of the bird’s behavior. Bird behavior is quantified in terms of the statistics of closest distance of approach, latency to approach, latency to sing, number of post-playback songs, number of flybys, percent of male-female duets, temporal correlation of individual song phrases, and number of singing competitions with neighboring subjects. Statistics of the properties of the measured spectrograms and spatial correlation properties for experiments are presented, and attempts are made to interpret the observed behavior and acoustical responses of the birds in the form of communication and territorial defense with the bird’s ability to estimate distance using the degradation (transmission loss and reverberation) of the playback calls. It was also observed that Thryothorus ludovicianus will respond to playback calls of Cardinalis cardinalis (Northern Cardinal) and this interaction between bird species is examined.

Differentiating the evolution of female song and male-female duets in the New World blackbirds: can tropical natural history traits explain duet evolution?

Female bird song and combined vocal duets of mated pairs are both frequently associated with tropical, monogamous, sedentary natural histories. Little is known, however, about what selects for duetting behavior versus female song. Female song likely preceded duet evolution and could drive apparent relationships between duets and these natural histories. We compared the evolution of female song and male-female duets in the New World blackbirds (Icteridae) by investigating patterns of gains and losses of both traits and their relationships with breeding latitude, mating system, nesting pattern, and migratory behavior. We found that duets evolved only in lineages in which female song was likely ancestral. Both female song and duets were correlated with tropical breeding, social monogamy, territorial nesting, and sedentary behavior when all taxa were included; however, correlations between duets and these natural history traits disappeared when comparisons were limited to taxa with female song. Also, likelihood values supported stronger relationships between the natural history traits and female song than between these traits and duets. Our results suggest that the natural histories thought to favor the evolution of duetting may in fact be associated with female song and that additional selection pressures are responsible for the evolution of duets.

Species-specific communication bars interspecific mating between syntopic species ofZwickniastoneflies (Plecoptera: Capniidae)

Most Northern Hemisphere stoneflies have species-specific mating signals that are generally thought to constitute a barrier against interspecific mating. We tested this hypothesis in two species of the genus Zwicknia that have only very recently been recognised as distinct species, and that were found to occur together in a stream in Lower Saxony, Germany. Analyses of molecular markers COI and 28S in combination with wing length (distinguishing males of both species) and mating signals revealed no instance of hybridisation among 23 studied specimens. In addition, eleven further males identified on the basis of morphology alone all produced the expected species-specific signal. Females and males of both species were presented with played back conspecific and heterospecific signals and duetting sequences, and responded only to conspecific stimuli. This lends support to the hypothesis that the intersexual communication system functions as an important pre-mating barrier against gene flow, although post-mating isolation cannot be excluded. Interspecific mating did occur when a mixed pair was confined together in a small container. Males of both species were found to call in response to played back duetting sequences with stereotypic latencies that are clearly longer than the latencies in male-female duets. We interpret this as an indication of eavesdropping behaviour coupled with attempts to take over the perceived duet. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 969–980.

Sex differences in the control of vocal pattern-generating circuitry in Xenopus laevis

Sex differences in the control of vocal pattern-generating circuitry in Xenopus laevis

Silent singers are not safe: selective response of a parasitoid to substrate-borne vibratory signals of stink bugs

The egg parasitoid Telenomus podisi Ashmead (Hymenoptera: Scelionidae) can eavesdrop on vibratory signals of adult stink bugs. Here, we tested the hypothesis that the parasitoid can selectively respond to the sex- and species-specific songs of different stink bugs. Two-choice plant bioassays were performed using dried bean plants with two expanded opposite leaves that were vibrated with played-back signals or with naturally produced signals from live insects placed on plants. Each leaf was vibrated with signals of the host Euschistus heros Fabricius (Hemiptera: Pentatomidae), the alternative host Piezodorus guildinii (Westwood) or the nonhost Chinavia impicticornis (Stål) (played back). Parasitoid females showed a selective response to the female songs of E. heros when these songs were tested against male songs or male–female duets. Telenomus podisi females also preferred E. heros female songs to female songs of the other pentatomid bugs tested. Our results show that T. podisi females respond selectively to female songs of their preferred host (E. heros); this behaviour may have relevant adaptive significance for the parasitoid, allowing it to forage in microhabitats with increased probability of finding host eggs. We discuss the ecological significance of the use of vibratory signals and interactions with other (chemical) cues during the host-searching behaviour of T. podisi.

A Cryptic New Species of Flycatcher (Tyrannidae: Suiriri) From the Cerrado Region of Central South America

AbstractA new species of tyrant flycatcher (Suiriri islerorum) is described from the cerrado region of Brazil and adjacent eastern Bolivia. The species previously had been confused with Suiriri suiriri affinis, with which it is syntopic at multiple sites. The new species was first identified by voice. Although cryptically similar to S. s. affinis in many respects, the new species is readily identified by all vocalizations, bill size, color pattern of the tail, and shape of the central rectrices. Most distinctive are the male–female duets, which are accompanied by dramatic wing-lifting displays not performed by any congeners. Reciprocal playback experiments of tape-recorded vocalizations demonstrated that the new species and S. s. affinis do not respond to one another's vocalizations. We provide information on the natural history of the new flycatcher, along with spectrograms of its various vocalizations. We also provide vocal analysis of all other named taxa in Suiriri, and discuss the various intrageneric relationships. In particular, S. s. affinis and S. s. bahiae, although distinct morphologically, are vocally and behaviorally similar, and respond to one another's vocalizations in playback experiments.

A CRYPTIC NEW SPECIES OF FLYCATCHER (TYRANNIDAE: SUIRIRI) FROM THE CERRADO REGION OF CENTRAL SOUTH AMERICA

Abstract A new species of tyrant flycatcher (Suiriri islerorum) is described from the cerrado region of Brazil and adjacent eastern Bolivia. The species previously had been confused with Suiriri suiriri affinis, with which it is syntopic at multiple sites. The new species was first identified by voice. Although cryptically similar to S. s. affinis in many respects, the new species is readily identified by all vocalizations, bill size, color pattern of the tail, and shape of the central rectrices. Most distinctive are the male–female duets, which are accompanied by dramatic wing-lifting displays not performed by any congeners. Reciprocal playback experiments of tape-recorded vocalizations demonstrated that the new species and S. s. affinis do not respond to one another's vocalizations. We provide information on the natural history of the new flycatcher, along with spectrograms of its various vocalizations. We also provide vocal analysis of all other named taxa in Suiriri, and discuss the various intragener...

Rapping, a female receptive call, initiates male-female duets in the South African clawed frog.

Finding a sexually receptive partner of the opposite sex is a challenge; one solution is to advertise. That advertising is usually the province of males has shaped scenarios for sexual selection, especially the ardent active male courting the passive but choosy female. Herein we consider an unusual case in which constraints on reproduction may have led to fertility advertisement by female frogs. When oviposition is imminent, female South African clawed frogs swim to an advertising male and produce an aphrodisiac call, rapping, that stimulates both male vocalization and approach. Males respond to rapping with a distinctive answer call. The rapping-answer interaction thus forms a duet between partners of a receptive pair.

Field playback of loud calls to gibbons ( Hylobates lar): territorial, sex-specific and species-specific responses

We present the results of an experimental study of territoriality among monogamous lar gibbons ( Hylobates lar), scoring vocal and movement responses to field playback of their loud calls. Playback of neighbouring groups' male-female duets on territory borders, and of these duets and music controls in territory centres, indicated a general territorial response. Responses to playback of a strange male's solo and of a strange female's solo in territory centres indicated that resident males would evict deeply intruding males and pairs but not necessarily females, and that resident females would evict deeply intruding females but probably not males or pairs. Vocal responses also implied that, although males carry the burden of routine territory defence in border disputes involving chases and special calls, the female part of the daily duet also contributes to routine exclusion of outside females. Responses of lar females to playback of the solo of a female capped gibbon ( H. pileatus) suggested that the females of one species cannot sex the calls of females of the other species. This could partly account for the existence of bigamous mixed-species groups at the interface between the two species. This result also implies that female calls contribute to routine exclusion of conspecific females, and thus to the maintenance of monogamy.