Female Calls Research Articles

Sexually distinct development of vocal pathways in Xenopus laevis

Deterministic rules, rather than experience, are thought to regulate the development of simple behaviors in vertebrates and invertebrates. We revisited this issue through examination of the sexually distinct vocalizations of African clawed frogs (Xenopus laevis), a reproductive behavior used by sexually mature males and females. We discovered that, as expected for simple behavior, female vocalizations develop through deterministic rules. The rare calls of juvenile females are indistinguishable from those of adult females. The vocal pathways of juvenile females, as measured by the contractile properties of the laryngeal muscles (the vocal muscles) and the laryngeal motoneuron somata (vocal motoneurons) size, are the developmental default and do not differentiate as they mature. Male Xenopus, in contrast, produce extensive vocalizations with rudimentary acoustic structure before reaching sexual maturity. Moreover, the functional properties of the vocal central pattern generator mature before muscle fibers and motoneuron size are fully masculinized. The results suggest that neuronal activity during development may be important in organizing the contractile properties of the muscle fibers in male, but not in female Xenopus.

Vocal behaviour of Crested Francolin Dendroperdix sephaena in response to playback calls

The Crested Francolin Dendroperdix sephaena is a common gamebird in sub-Saharan Africa but its vocal behaviour is poorly recorded. A fixed area (24 km2) in the Borakalalo National Park (North West province, South Africa) was traversed during December 2007 to January 2009 and 140 Crested Francolin groups were enticed with playback calls and their calls recorded. The coveys were recorded to identify different calls and to capture statistics on call characteristics during the breeding and non-breeding seasons. Sonograms were produced to analyse and compare the structural characteristics of calls. The Crested Francolin possesses a basic communication system of eight distinctive calls that is similar to the repertoire size of other non-passerines. The duet is a cooperative call by a male and female to advertise, among other functions, territorial occupancy. Males produce a call similar to but different from the duet that advertises reproductive neutrality to avoid physical clashes. Male and female calls could be mate selection tools in dense bush that optimise the chance of fit males and females that roam in the population to pair.

A novel female call incites male–female interaction and male–male competition in the Emei music frog, Babina daunchina

In anurans, females generally remain silent during mating or only produce calls of very low intensity before mating. Consequently the functions of female calls are not as well understood as those produced by males. We investigated a novel female call produced during mating in the Emei music frog. The functions of the female call during reproductive behaviours were evaluated by field and seminatural playback experiments. During mating, low-intensity female calls (approximately 3.2 s in duration) alternated with male sexual movements (approximately 1.34 s in duration). Female calling was sometimes prolonged when we interrupted male movements, which is consistent with the idea that female calls may stimulate male sexual activity and perhaps facilitate ovulation. In their natural environment, Babina males vocalize and mate in well-hidden underground nests. Field playback experiments showed that female calls significantly increased the rate of male advertisement calling which may help females locate males. Males also showed significant positive phonotactic responses to playback of female calls, and increased aggressive call production and other aggressive behaviours which females may use as cues for mate selection.

Reproductive behaviour of Crocidosema (=Epinotia) aporema (Walsingham) (Lepidoptera: Tortricidae): temporal pattern of female calling and mating

Crocidosema aporema (Walsingham) is a major pest of legumes in the southern cone of Latin America. The mating behaviour of two allopatric populations (Uruguay and Brazil) of C. aporema kept in captivity was studied by observing the posture of calling females, the temporal pattern of pheromone emission and mating, and the response of males to calling females in olfactometer tests. Female calling and mating was observed during the scotophase, from the first to the seventh night after adult emergence. Male response was evaluated at night using a single calling female in a Y-shaped olfactometer. Females adopted a characteristic calling posture, extruding the pheromone gland from the tip of the abdomen. Most females started calling during the second scotophase, and all females called from the third, between the fifth and seventh hours after the onset of the scotophase. Most of the couples mated once throughout the experiment, between the third and sixth night and during the middle of the dark phase. Males preferentially chose the female arm in olfactometer tests, considering both the first arm chosen and the number of visits during the observation period. Our results describe for the fi rst time the temporal pattern associated to the reproductive behaviour of C. aporema. We also provide evidence that this tortricid is monoandrous, and that pheromones are used in intersexual communication for mate finding. Our data will be used to optimize the collection of female sex pheromones for chemical characterization in order to develop a monitoring tool for this pest.

Siberian crane duet as an individual signature of a pair: comparison of visual and statistical classification techniques

Vocal individuality varies between species and/or ontogenesis stages depending on needs in the vocal recognition, but also estimation of individual differences depends on the method of analysis. We studied pair-specific differences of duets elicited by mating pairs of Siberian crane Grus leucogeranus. We quantitatively described the duet structure and compared visual and statistical classification methods of pair identification by duet. Three methods were used: discriminant analysis, method of classification trees and visual classification of spectrogram. We found significant interpair differences. The pairs differ by duet structure that is by the ratio of male- and female-initiated duets and by the ratio of the number of male to female calls; temporal-frequency duet characteristics are pair-specific, too. All methods showed high interpair differences, which exceeded random values significantly. Discriminant analysis stepwise procedure based on 11 parameters resulted in 97.3% of correctly assigned duets. Human observers correctly assigned 80.7% of spectrograms. Our data provide a basis for remote monitoring of this endangered species with a wild population of only 3,000 birds.

Individual recognition and potential recognition errors in parent–offspring communication

The recognition of food-provisioning parents is crucial for fledglings of many bird species. Vocalizations are the most commonly used cues in avian parent–offspring communication, and it has been shown in several species that fledglings respond specifically to their parents' contact calls. However, fledglings occasionally also react to unrelated adults. Such responses may reflect recognition errors or alternatively a strategy of fledglings to obtain food or other direct benefits from unrelated adult birds. In a playback experiment, we tested whether zebra finch Taeniopygia guttata fledglings perceive variation in adult call signatures to recognize their parents and whether the propensity to respond to unrelated individuals is related to the gender of adults and to signal properties of male and female calls. Male calls are learnt and show high intra-sexual variation, which may improve the accurate recognition of the father's individual signature. In contrast, calls of adult females are innate, show lower intra-sexual variation such that the mother's call is more likely to be confused with another female call. We demonstrate that fledglings are able to recognize their parents. In addition, fledglings reacted more strongly to unrelated females compared with unrelated males. Our findings suggest that responses to unrelated adults may reflect recognition errors and indicate the importance of variation in identity signals for individual recognition processes in parent–offspring communication.

What can Captive Whales tell us About their Wild Counterparts? Identification, Usage, and Ontogeny of Contact Calls in Belugas (Delphinapterus leucas)

Contact calls are ubiquitous in social birds and mammals. Belugas are among the most vocal of cetaceans, but the function of their calls is poorly understood. In a previous study we hypothesized that a broad band pulsed call type labeled “Type A,” serves as a contact call between mothers and their calves. Here we examined context-specific use of call types recorded from a captive beluga social group at the Vancouver Aquarium, and found that the Type A call comprised 24% to 97% of the vocalizations during isolation, births, death of a calf, presence of external stressors, and re-union of animals after separation. In contrast it comprised 4.4% of the vocalizations produced during regular sessions. We grouped 2835 Type A calls into five variants, A1 to A5. A discriminant function analysis classified 87% of calls in the same groupings that we assigned them to by ear and visual examination of spectrograms. The variants do not represent individual signatures. One variant, A1, was used by three related individuals: an adult female, her male calf and his juvenile half-sister. Our previous research documented the gradual development of the A1 variant by the male calf, until at 20 months he was producing stereotyped renditions of his mother and sister’s A1. We used our findings to generate testable predictions about the usage of these signals by wild belugas. We verified the existence of signals with the same distinctive features as the contact calls found in captivity in the repertoire of St. Lawrence Estuary herds, and documented their usage by two wild individuals from different populations. In the St. Lawrence, these were emitted by a female calling after a dead-calf. In Hudson Bay, by a temporarily restrained juvenile. We propose that these calls function in nature, a sin captivity, to maintain group cohesion, and that the variants shared by related animals are used for mother-calf recognition.

Female giant panda ( Ailuropoda melanoleuca ) chirps advertise the caller's fertile phase

Although female mammal vocal behaviour is known to advertise fertility, to date, no non-human mammal study has shown that the acoustic structure of female calls varies significantly around their fertile period. Here, we used a combination of hormone measurements and acoustic analyses to determine whether female giant panda chirps have the potential to signal the caller's precise oestrous stage (fertile versus pre-fertile). We then used playback experiments to examine the response of male giant pandas to female chirps produced during fertile versus pre-fertile phases of the caller's reproductive cycle. Our results show that the acoustic structure of female giant panda chirps differs between fertile and pre-fertile callers and that male giant pandas can perceive differences in female chirps that allow them to determine the exact timing of the female's fertile phase. These findings indicate that male giant pandas could use vocal cues to preferentially associate and copulate with females at the optimum time for insemination and reveal the likely importance of female vocal signals for coordinating reproductive efforts in this critically endangered species.

Male and female contact calls differentially influence behaviour in a cockatoo, the Galah (Eolophus roseicapillus)

Even in species in which males and females share a repertoire of calls, subtle sex differences in vocalisations often exist, particularly in calls used for long-distance communication. However, few studies address whether birds respond differently to similar male and female calls. This study investigated whether an Australian cockatoo, the Galah (Eolophus roseicapillus), responds differentially to three types of loud calls (Double Chet, Chechet and Chewp) commonly produced by both sexes. I played back male and female vocalisations to wild Galahs in Canberra, Australia, and recorded vocal and approach responses. Galahs responded differently to at least one call type, with birds approaching male Double Chets more closely but vocalising more to female Double Chets. Males were more likely than females to vocalise to Double Chets and Chechets, regardless of stimulus sex. These results suggest that males may have to expend more effort than females in forming affiliative relationships. Although males and females exhibited different vocal behaviour, paired males and females tended to approach stimuli together, which may indicate that coordination of movement, rather than coordination of vocal behaviour, is important in maintaining the pair-bond. These experiments show that even when the sexes share a repertoire, the sender and receiver sex may influence the nature of a vocal interaction.

Calling Behavior and Rhythms of Sex Pheromone Production in the Black Cutworm Moth in China

The hourly and daily variation of calling behavior and sex pheromone production by the female black cutworm moth, Agrotis ypsilon (Rottemberg), were investigated. Both calling behavior and titers of five sex pheromone components showed distinct diel rhythms, and peak periods of calling and pheromone titer were synchronous. Females began to call on the first night after eclosion and called mainly during the second half of the scotophase. The percentage of females calling increased in 1 to 3-d-old females and decreased in 3 to 7-d-old females. Females advanced their calling time with increasing age (1 to 7 d). GC-MS analysis of hexane extracts of pheromone glands revealed that the titers of the five sex pheromone components were very low on the first night after eclosion, but increased sharply and peaked on the third night. Titers decreased greatly with increasing age (3 to 7 d), but from the onset of the scotophase to 4.5 h into scotophase, titers remained invariate. However, from 4.5 to 7 h, pheromone titers, especially that of the primary component Z7-12:Ac, increased sharply and peaked. After the peak, the titers decreased greatly at 8 h, and thereafter decreased gradually to the level before 4.5 h. The quantity of each component almost reached zero after lights-on.

Differential responsiveness in brain and behavior to sexually dimorphic long calls in male and female zebra finches

In zebra finches (Taeniopygia guttata), as in most other songbird species, there are robust sex differences in brain morphology and vocal behavior. First, male zebra finches have larger song system nuclei--involved in sensorimotor learning and production of song--than females. Second, male zebra finches learn their song from a tutor, whereas female zebra finches develop a learned preference for the song of their father but do not sing themselves. Third, female zebra finches produce an unlearned "long call," while males learn their long call (which is different from that of females) from their song tutor. We investigated behavioral and molecular neuronal responsiveness to this sexually dimorphic communication signal. Behavioral responsiveness was quantified by measuring the number of calls and approaches in response to calls that were broadcast from a speaker. We quantified neuronal activation by measuring the number of neurons expressing Zenk, the protein product of the immediate early gene ZENK, in a number of different forebrain regions in response to male calls, to female calls, or to silence. In both sexes female calls evoked more calls and approaches than male calls. There was significantly greater Zenk expression in response to female calls compared to silence in the caudomedial nidopallium, caudomedial mesopallium, and the hippocampus in females, but not in males. Thus, male and female zebra finches both show a behavioral preference for female calls, but differential neuronal activation in response to sexually dimorphic calls.

Time‐shifted reproductive behaviours among fall armyworm (Noctuidae: Spodoptera frugiperda) host strains: evidence for differing modes of inheritance

The noctuid moth Spodoptera frugiperda consists of two strains associated with different larval host plants (most notably corn and rice). These strains exhibit differential temporal patterns of female calling and copulation during scotophase, with the corn strain more active earlier in the night. We investigated strain-specific constraints in reproductive timing, mating interactions between the two strains, and the mode of inheritance of timing of female calling, male calling, copulation and oviposition. We observed an allochronic shift of all reproductive behaviours by approximately 3 h and a parallel shift of nonreproductive locomotor activity, suggesting involvement of the circadian clock. The corn strain was more variable in the timing of calling and copulation than the rice strain. Rice strain females were more restricted in the timing of copulation than rice strain males, while such differences between the sexes were not apparent in the corn strain. There were significant interactions between the strains affecting onset times of copulation and male calling. The four investigated reproductive traits differed in their modes of inheritance: timing of female and male calling exhibited strong maternal effects, timing of copulation was controlled by a combination of maternal effects and corn strain dominant autosomal factors, and timing of oviposition was inherited in a corn strain dominant fashion. We conclude that the allochronic separation of reproduction between fall armyworm strains is asymmetric, less pronounced than previously thought, and under complex genetic control.

Geographic variation in vocalizations of pups and mother-pup behavior of harp seals Pagophilus groenlandicus

All harp seal populations form breeding aggregations on the Arctic pack ice. However, pack ice conditions vary spatially and temporally among these aggregations with variation in envi- ronmental and oceanographic conditions, which may affect the behavioral interactions between mothers and their newborn pups. We investigated the variation in mother-pup behavior between harp seal breeding aggregations in the NE (Greenland Sea) and NW Atlantic coastal shelf region (Front). Acoustic cues provided by the pups are thought to be important in facilitating reunions with their mothers. Consequently, we measured variation in vocal parameters among seals to investigate geographic differences in pup vocalizations. Classification trees showed a distinctive split between Front and Greenland Sea pup vocalizations. There were no clear differences between male and female pups at the Front, where 42% of male and 38% of female pup calls could be attributed to a given individual. This contrasts with the Greenland Sea, where 55% of vocalizations of female pups were attributed to individuals compared with only 8% for males. Analyses of behavioral observations of mother-pup pairs made in the afternoon and evening showed that pups in the Greenland Sea suck- led more and were more alert than pups in the Front. Further, mother-pup attendance patterns dif- fered between sites. Mothers at the Front attended their pups 85.1% of the time, whereas mothers in the Greenland Sea attended their pups 52.2% of the time. These substantial differences between sites might be related to evolutionary changes in behavior resulting from commercial hunting or vari- able environmental conditions.

Pupal Development, Longevity and Behavior ofCarmenta theobromae(Lepidoptera: Sesiidae)

ABSTRACT Pupal duration, longevity, and behavior of males and females of Carmenta theobromae (Busck), an insect pest of economic importance in cocoa plantations (Theobroma cacao (L.)) were studied. Perforated pods from cocoa farms in Curiepe, Miranda state, Venezuela were collected and taken to INIA-Miranda. Carmenta theobromae larvae and pupa were extracted from infested pods. All stages (larvae, pupae, and adults) were kept at 28 ± 5°C, 70 ± 15% RH and a photoperiod 12: 12 (L:D). Emergence and daily activity of adults kept in observation chambers was recorded. Pupal development time was 12.78 ± 2.50 d and adult longevity was 5.10 ± 1.96 and 4.39 ± 1.57 d for males and females, respectively. Emergence of adults began between 0730 and 0800 h, and continued until 1400 and 1500 h for females and males, respectively. Adult emergence peaked at 0800 h for both sexes, and the adult sex ratio was 1.2:1 (male: female). Female calling behavior occurred between 1430 and 1930 h, with a pronounced peak at 1730 h, and...

A sex attractant of the rough bollworm, Earias huegeliana (Gaede) (Lepidoptera: Noctuidae)

The sex attractant of the rough bollworm was identified using gas chromatography and mass spectrometry (GC-MS) from female gland and air collections. Identified compounds were formulated into blends and tested in the field for attractiveness to males. The Gas chromatograph-mass spectrometry (GC-MS) analysis revealed 4 compounds, (E,E)-10,12-hexadecadienal, (E,E)-10,12-hexadecadienol, (Z)-11-hexadecenal and (Z)-11-octadecenal in a ratio of 4:1:1:1 in the gland extracts. (E,E)-10, 12-hexadecadienol was not detected in the air collections. Field bioassay showed the 2 components, (E,E)-10,12-hexadecadienal and (Z)-11-hexadecenal to be essential for activity of the blend. This blend was highly attractive to males only. 2 trap designs, the funnel and delta traps were tested and the delta trap was the better of the 2. Male response to attractant baited traps was found to be in the second half of the night, between 0200 and 0500 h. This was found to be synchronised to female calling time. Use of the attractant blend developed as part of the integrated pest management system in cotton is discussed. Key words: Rough bollworm, (E,E)-10,12-hexadecadienal, (E,E)-10,12-hexadecadienol, (Z)-11-hexadecenal, (Z)-11-octadecenal, pheromone traps, gas chromatograph-mass spectrometry, sex attractant.

Delayed onset of vocal recognition in Australian sea lion pups (Neophoca cinerea)

In pinnipeds, maternal care strategies and colony density may influence a species' individual recognition system. We examined the onset of vocal recognition of mothers by Australian sea lion pups (Neophoca cinerea). At 2 months of age, pups responded significantly more to the calls of their own mothers than alien female calls demonstrating a finely tuned recognition system. However, newborn pups did not respond differentially to the calls of their mother from alien female calls suggesting that vocal recognition had not yet developed or is not yet expressed. These findings are in stark contrast to other otariid species where pups learn their mother's voice before their first separation. Variance in colony density, pup movements, and natal site fidelity may have reduced selective pressures on call recognition in young sea lions, or alternatively, another sensory system may be used for recognition in the early stage of life.

Social context influences acoustic communication in zebra finches.

During communication, a signal conveys information between an emitter and a receiver, but indirect receivers can eavesdrop on the interaction. In birds, communication has been demonstrated to often be under the influence of this eavesdropping. Social species show complex communication networks where audience drives individual behaviors. Zebra finches (Taeniopygia guttata) are gregarious songbirds that live in social groups and form life‐long pair‐bonds. Previous studies showed that the vocal behavior of males highly depends on this audience effect. Males show mate calls preference over other female calls in the presence of an established male‐female pair, but not in the presence of unmated male‐female or male‐male dyads. Males in social groups also show stronger vocal response to female calls than males in social isolation. In this study, we investigate whether female calls of varied social salience evoke differently male calling according to the audience. We show that social context modifies not only call rate in response to female calls of varied social salience, but also acoustic structure of evoked calls. Thus male distance calls are not stereotyped calls whose acoustic cues only convey bird’s identity. We propose that fine spectral modifications of the calls could carry information about the emitter motivation.

Intersexual food transfer among orangutans: do females test males for coercive tendency?

Tolerated transfer of food among adults is rare among primates, except in humans. Here, we present data on a consistent pattern of tolerated intersexual transfer of food (held in hand, foot, or mouth by the owner) among adult orangutans, in two different natural populations (Pongo abelii and Pongo pygmaeus wurmbii), based on ca. 9,000 h of focal observation per site. Although rare, intersexual food transfers were disproportionately from males to sexually active females and involved food that was equally available to both sexes. There was no evidence for direct trading of food for social favors (mating, grooming, or agonistic support) or for sharing under pressure of harassment. However, females frequently protested with loud screams when males, especially unflanged ones, attempted to take food they possessed, and also when males responded aggressively to their taking attempt. Since associations ended sooner when the female emitted noisy calls, a male who did not allow a female to take food from him risked losing the association. These findings support the hypothesis that by taking food, a sexually active female may test the male's tendency toward violence. Thus, intersexual food taking in orangutans is based on female leverage, resulting in a species-wide female entitlement to male “generosity”. The inhibition of food defense required for this kind of transaction may also form the basis for sharing patterns among species in which nutritional benefits have become important, such as chimpanzees and perhaps human foragers.

Lifespan in male ants linked to mating syndrome

Male ants have long been thought to leave the nest, swarm, mate and die in quick succession (male aggregation syndrome). However, the ancestors of the ants likely used female calling, where females advertise with pheromones for longer lived and presumably free living males. In this study, male lifespan was compared in four species from a Panama rain forest. Males of two species with aggregation syndrome (Atta colombica and Azteca sp.) lived only days after collection at a light trap, and their lifespan failed to increase when supplied sugar water ad libitum. In contrast, two species with female calling syndrome (Ectatomma ruidum and Paraponera clavata) lived up to 116 days when fed. These results link male lifespan to mating systems, and provide a framework to examine variation in how ant colonies invest in males.

Phenology and population radiation of the nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae) in Hawai’i

The nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae), is an invasive pest with established populations on three Hawai’ian islands. Indigenous to Southeast Asia, D. pallivitta caterpillars cause defoliation of ornamental nursery stock and pose a human health hazard due to their urticating hairs that can cause painful skin reactions. Identification of the pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOnBu) from D. pallivitta has made it possible to investigate the phenology and population dynamics using baited traps. Male captures in Jackson traps baited with E7,9-10:COOnBu showed a vegetation preference for tall-grass fields and forest/grass interfaces over forest areas. Microlocation preferences were also found for trap height, with over 65% of males being caught in traps suspended at 1 m, compared with the traps at 3 and 5 m. Captures of male moths in traps baited with live females, and direct observations of female calling behavior, showed peak activities 6–7 h after the onset of scotophase. This is a much later communication period than for D. bradleyi and D. trima and may provide a mechanism by which D. pallivitta maintains reproductive isolation in areas where all three species are present. Coastal and inland transects established in eastern Hawai’i measured aspects of population fluctuations and radiation into new areas with relation to elevation and microclimate. Population expansion was measured by comparing moth population means and 80% population boundaries over time. Both population measures showed a higher expansion for the coastal transect. Differences in population expansion may be attributed in part to temperature and elevation, while precipitation does not seem to have a strong effect. Both the behavioral and ecological data collected can be used to optimize deployment of detection/control strategies and to predict population expansion/risk assessment for establishing quarantine protocols for the nettle caterpillar.