Male Calls Research Articles

Sexual behavior and chemical signaling in Opsiphanes cassina (Lepidoptera: Nymphalidae)

Behavior modification using chemical stimuli is a promising tactic for integrated management of lepidopteran pests. Therefore, this approach was evaluated for the management of the butterfly Opsiphanes cassina Felder 1862, a defoliating pest in oil palm plantations. To achieve this aim, we observed adults’ sexual behavior under laboratory conditions and identified glandular structures in the abdomen and hind wings of males that are associated with the production of sexual pheromones in taxonomically related insects. It was also determined that male calls to females occur at 18:00 h when they fill their glandular structures, tremble, and make abdominal movements while possibly releasing pheromones. The hairpencils of the hind wings are also exposed during this time. Furthermore, the analysis using Gas Chromatography-Mass Spectrometry (GC–MS) on the samples obtained by Solvent Assisted Extraction (SAE) revealed the identification of three male-specific volatile organic compounds (VOCs), including (E)-nerolidol, vanillin, and (Z)-7-heptadecene. The Electroantennographic (EAG) evaluation demonstrated that females respond to the compounds, indicating their likely involvement in intraspecific interactions of the species. However, the behavioral evaluation did not confirm their attractive effect under the conditions employed. Nevertheless, the identified male-specific semiochemicals could be an alternative for inclusion in integrated pest management (IPM) of this pest in oil palm crops. Therefore, it is recommended to evaluate them under field conditions.

Monitoring the Green and Golden Bell Frog Litoria aurea on the Crookhaven floodplain at Nowra, New South Wales from 2016-2022 and implications for conservation

ABSTRACT Systematic (time constrained) and targeted surveys were conducted for the Green and Golden Bell Frog Litoria aurea from 2016-2022 on the Crookhaven River - Shoalhaven River floodplains, on the south coast of New South Wales. Systematic nocturnal surveys were conducted at 30-34 sites, three to four times between October and March. Litoria aurea were observed at 20 sites and males were heard calling at five of these. The majority of detections during the breeding season (January - February) were in flooded areas of Terara Swamp and Brundee Swamp, while outside the breeding season more frogs were seen in the catchment of Rotten Creek, the largest tributary of Brundee Swamp. Ten of the systematic sites were ponds constructed for the species as offsets for various developments. Breeding activity (calling males) was detected at two of these offset ponds, but no tadpoles or juveniles were found. The number of frogs detected during systematic surveys varied from eight to forty-four per season, while the number found during diurnal surveys of 136-175 sites annually ranged from zero to thirty-three. Although recruitment occurred in most years the population did not recover to that previously found in 2010-2012. The lack of recovery was influenced by drought, wildfire and a continual loss of habitat from urban developments. Large adult females were seen each survey beside Rotten Creek or nearby ponds suggesting the adult population overwinters within the catchment of this creek and disperse down this catchment to Brundee Swamp to breed in spring. The results from six years monitoring indicate the Crookhaven L. aurea population has not recovered in abundance and distribution since 2010-2012. The three most abundant species of frog Litoria fallax, Litoria peroni and Limnodynastes peroni were also analysed for site preference and population variations over the survey.

Phenotypic plasticity of male calls in two populations of the katydid Neoconocephalus triops (Insecta: Tettigoniidae)

The ability to respond to environmental changes plays a crucial role for coping with environmental stressors related to climate change. Substantial changes in environmental conditions can overcome developmental homeostasis, exposing cryptic genetic variation. The katydid Neoconocephalus triops is a tropical species that extended its range to the more seasonal environment of North America where it has two reproductive generations per year. The harsher winter conditions required adults to diapause which resulted in substantially different mating calls of the diapausing winter animals compared to the non-overwintering summer animals in northern Florida. The summer call corresponds to that of tropical populations, whereas the winter call represents the alternative call phenotype. We quantified call plasticity in a tropical (Puerto Rico) and a temperate population of N. triops (Florida) that differ in experiencing winter conditions in their geographic regions. We hypothesized that the plastic call traits, i.e., double-pulse rate and call structure, are regulated independently. Further, we hypothesized that phenotypic plasticity of double-pulse rate results in quantitative changes, whereas that of call structure in qualitative changes. We varied the photoperiod and duration of diapause during male juvenile and adult development during rearing and analyzed the double-pulse rate and call structure of the animals. Double-pulse rate changed in a quantitative fashion in both populations and significant changes appeared at different developmental points, i.e., the double-pulse rate slowed down during juvenile development in Florida, whereas during adult diapause in Puerto Rico. In the Florida population, both the number of males producing and the proportion of total call time covered by the alternative call structure (= continuous calls) increased with duration spent in diapause. In the Puerto Rico population, expression of the alternative call structure was extremely rare. Our results suggest that the expression of both pulse rate and call structure was quantitative and not categorical. Our systematic variation of environmental variables demonstrated a wide range of phenotypic variation that can be induced during development. Our study highlights the evolutionary potential of hidden genetic variation and phenotypic plasticity when confronted with rapidly changing environments and their potential role in providing variation necessary for communication systems to evolve.

Mating and post-copulation behavior in the tea leafhopper, Empoasca onukii (Hemiptera: Cicadellidae).

The tea leafhopper, Empoasca onukii, relies on substrate-borne vibrations for sexual communication and is mainly controlled with chemical pesticides, which poses risks to the environment and food safety. Based on previous studies, we conducted a series of behavioral assays by simultaneous observation of vibration signals and movement to investigate the mating and post-copulation behavior of tea leafhoppers. During mating, the activity of E. onukii was restricted to dawn and dusk and concentrated on the sixth or seventh mature leaf below the tea bud. By comparing the time spent in locating females among different males, the timely reply of females was the key factor affecting mating success. Empoasca onukii females mated only once in their lives, while males could mate multiple times. Male rivalry behavior involved two distinct strategies. The rivals could send disruptive pulses to overlap the male calling signals, locate the courting males, and drive them away after contact. Some rivals could emit mating disruption signals (MDSs) to interrupt the ongoing identification duet and establish their own mating communication. Both identification and location duets could be interrupted by playback of MDSs, which is essential to create effective synthetic signals to disrupt mating communication of E. onukii. Our study clarified the spatial and temporal distribution of E. onukii in mating and the function of MDSs, which will be essential to develop future vibrational mating disruption techniques for E. onukii and its energy-efficient application in the field.

Revision of Litoria rothii (Anura: Pelodryadidae) from northern Australia.

Litoria rothii is a widespread pelodryadid frog with a charismatic laughing advertisement call, distributed across the Australian Monsoon Tropics and southern New Guinea. Given its large distribution spanning well-known biogeographic barriers, variation in male advertisement calls and the prevalence of unresolved species complexes in the Australian frog fauna, we examine the genetic, morphological and acoustic diversity in the species from across its range. Our analyses reveal the presence of a previously unrecognised species in western parts of the range of L. rothii sensu lato, which we describe herein as a new species. Litoria ridibunda sp. nov. is distinguished from L. rothii on the basis of paraphyly of nuclear gene trees with L. everetti from Indonesia, colour patterns on the posterior thigh and male advertisement calls. Compared to L. rothii, the new species has a less contrasting pattern on the posterior thigh and a male advertisement call with a greater number of notes per call and a greater call duration. In particular, the magnitude of call differences between the species is highest where the ranges of the two species are in proximity in north-western Queensland. Our study further emphasises the undiagnosed diversity that remains in Australian frogs, even in relatively large, charismatic, frequently encountered species that often share human dwellings.

Sound processing in the cricket brain: evidence for a pulse duration filter.

The auditory system of female crickets allows them to specifically recognize and approach the species-specific male calling song, defined by sound pulses and silent intervals. Auditory brain neurons form a delay-line and coincidence detector network tuned to the pulse period of the male song. We analyzed the impact of changes in pulse duration on the behavior and the responses of the auditory neurons and the network. We confirm that the ascending neuron AN1 and the local neuron LN2 copy the temporal structure of the song. During ongoing long sound pulses, the delay-line neuron LN5 shows additional rebound responses and the coincidence detector neuron LN3 can generate additional bursts of activity, indicating that these may be driven by intrinsic oscillations of the network. Moreover, the response of the feature detector neuron LN4 is shaped by a combination of inhibitory and excitatory synaptic inputs, and LN4 responds even to long sound pulses with a short depolarization and burst of spikes, like to a sound pulse of natural duration. This response property of LN4 indicates a selective auditory pulse duration filter mechanism of the pattern recognition network, which is tuned to the duration of natural pulses. Comparing the tuning of the phonotactic behavior with the tuning of the local auditory brain neurons to the same test patterns, we find no evidence that a modulation of the phonotactic behavior is reflected at the level of the feature detector neurons. This rather suggests that steering to nonattractive pulse patterns is organized at the thoracic level.NEW & NOTEWORTHY Pulse period selectivity has been reported for the cricket delay-line and coincidence detector network, whereas pulse duration selectivity is evident from behavioral tests. Pulses of increasing duration elicit responses in the pattern recognition neurons, which do not parallel the behavioral responses and indicate additional processing mechanisms. Long sound pulses elicit rhythmic rebound activity and additional bursts, whereas the feature detector neuron reveals a pulse duration filter, expanding our understanding of the pattern recognition process.

Social regulation of androgenic hormones and gestural display behavior in a tropical frog

Many animals use forms of gesture and dance to communicate with conspecifics in the breeding season, though the mechanisms of this behavior are rarely studied. Here, we investigate the hormone basis of such visual signal behavior in Bornean rocks frogs (Staurois parvus). Our results show that males aggregating at breeding waterfalls have higher testosterone (T) levels, and we speculate that this hormone increase is caused by social cues associated with sexual competition. To this end, we find that T levels in frogs at the waterfall positively predict the number waving gestures—or “foot flags”—that males perform while competing with rivals. By contrast, T does not predict differences in male calling behavior. In these frogs, vocal displays are used largely as an alert signal to direct a rival's attention to the foot flag; thus, our results are consistent with the view that factors related to reproductive context drive up T levels to mediate displays most closely linked to male-male combat, which in this case is the frog's elaborate gestural routine.

Critical calls: Circadian and seasonal periodicity in vocal activity in a breeding colony of Panamanian golden frogs (Atelopus zeteki).

The Panamanian golden frog (Atelopus zeteki) is a critically endangered species and currently is believed to survive and reproduce only in human care. Panamanian golden frog males are considerably vocal which may be an important component in their successful reproduction, though little is currently known about their calls. To better understand the behavior and vocal patterns of this species and to improve breeding efforts in the assurance colony, we employed individual sound recording of male advertisement calls and acoustic monitoring of a breeding colony to investigate variation in the vocal behavior of Panamanian golden frogs. The goal was to capture variability within and among frogs as well as patterns of periodicity over time. First, the advertisement calls from individual male Panamanian golden frogs were recorded, and acoustic parameters were analyzed for individual differences. Results suggest that male advertisement calls demonstrate individual- and population specificity. Second, data collected through a year-long acoustic monitoring of the breeding colony were investigated for circadian and circannual periodicity. Male vocal activity revealed a circadian periodicity entrained by the daily light schedule. Seasonal periodicity was also found with highest vocal activities between December and March. The finding of a seasonal periodicity is worth noting given that the population had been bred for 20 years under constant environmental conditions. Finally, results suggest that vocal activity was responsive to daily animal care activity. Vocal activity decreased substantially when personnel entered the room and engaged in animal husbandry activities. The findings illustrate the usefulness of acoustic monitoring to provide insight into animal behavior in a zoo setting in a key breeding colony of endangered animals, and calling pattern observations may be utilized to modify husbandry practices to improve Panamanian golden frog breeding success and general care.

The functions and evolution of graded complex calls in a treefrog

ABSTRACT Variation in signal complexity is common among different species. Understanding why some species have evolved extensive call complexity can offer insight into the evolution of complex signals. In this study, we investigated the functions of different call types in a treefrog using call network analysis, male playback experiments, and correlation analysis between call properties and body size. Our results show that the male treefrogs can produce three kinds of notes that can be combined to produce single-note call types as well as composite calls. We also identified an intermediate note type between the advertisement call and suppress call, indicating that male suppress calls may have evolved from advertisement calls. The call network revealed functional correlation and distinction between different calls. Additionally, our study revealed that the dominant frequencies of the advertisement calls and suppress calls can signal the size of calling males. Male frogs can combine different notes in different sequences to form graded complex calls, which may perform different communication functions. Our results indicate that different communication needs may drive the evolution of signal complexity, which provides new evidence to the social complexity hypothesis and deeper insights into the function and complexity of animal acoustic communication.

Stonefly drumming behavior descriptions of three Soliperla Ricker, 1952 species (Plecoptera: Peltoperlidae)

One new drumming call signal description and two updated call descriptions of three Soliperla Ricker, 1952 species in the stonefly family Peltoperlidae are presented. It was determined after recording and analysis that these signals differed from the previous descriptions, warranting a revision. Percussive signal interval patterns for the three species are described for the first time. The previous monophasic call signal pattern descriptions of Soliperla quadrispinula (Jewett, 1954) and S. thyra (Needham & Smith, 1916) are updated to the repeated monophasic pattern. The male call and response of S. sierra Stark, 1983 and the response signal of S. quadrispinula are described for the first time. The call descriptions of the three California species consist of one to six monophasic signals with inconsistent inter-call intervals. Sequenced monophasic female answers did not follow all repeated male calls. Male monophasic responses occasionally followed female answers in sequenced 3-way exchanges.

Difference in the songs of paired and unpaired southern yellow-cheeked gibbon males (Nomascus gabriellae): social status or age?

All gibbons (Primates: Hylobatidae) are well known for emitting loud vocalizations specific for species and sex. The songs of paired and unpaired male southern yellow-cheeked gibbons (Nomascus gabriellae) are characterized by the presence of staccato notes and multi-modulation phrases with two or more extremely rapid frequency modulations in the second note of each phrase. In addition, paired males also produce a coda vocalization, which is similar to the multi-modulation phrase of male calls but lacks the staccato notes and always occurs directly following the female great call as part of a pair-specific duet. The aim of this study was first to assess whether the songs of paired and unpaired males can be acoustically distinguished from one another and second, whether the coda vocalization differs from the multi-modulation phrase of the male call in paired males. To assess these issues, we analyzed 616 songs obtained from a long-term study of vocal development in 14 captive adult males (>7 years old), half of which were unpaired and significantly younger than paired subjects. For each song, we quantified nine acoustic features, for which we applied a suite of linear mixed effects models with social status as a fixed variable and age as a regression coefficient. This allowed us to compare (1) the structure of male calls (staccato notes and multi-modulation phrase) between paired and unpaired subjects, (2) the muti-modulation phrase of unpaired subjects to the coda vocalization of paired subjects, and (3) the multi-modulation phrase of paired males to the coda vocalization. We found that the male call of younger-unpaired subjects had a longer duration, broader frequency range, higher maximum frequency, and fewer staccato notes than their counterparts in paired subjects. The coda vocalization of older-paired males exhibited a larger number of frequency modulations than the multi-modulation phrase of all males. While the male call of younger-unpaired males differs from both the male call and the coda vocalization of older-paired males, further studies are necessary to disentangle the effects of age and pairing status.

Electromagnetic field exposure affects the calling song, phonotaxis, and level of biogenic amines in crickets

The electromagnetic field (EMF) is ubiquitous in the environment, constituting a well-known but poorly understood stressor. Few studies have been conducted on insect responses to EMF, although they are an excellent experimental model and are of great ecological importance. In our work, we tested the effects of EMF (50 Hz, 7 mT) on the cricket Gryllus bimaculatus: the male calling song pattern, female mate choice, and levels of biogenic amines in the brain. Exposure of males to EMF increased the number and shortened the period of chips in their calling song (by 2.7% and 5% relative to the control song, respectively), but not the sound frequency. Aged (3-week-old) females were attracted to both natural and EMF-modified male signals, whereas young (1-week-old, virgin) females responded only to the modified signal, suggesting its higher attractance. Stress response of males to EMF may be responsible for the change in the calling song, as suggested by the changes in the amine levels in their brains: an increase in dopamine (by 50% relative to the control value), tyramine (65%), and serotonin (25%) concentration and a decrease in octopamine level (by 25%). These findings indicate that G. bimaculatus responds to EMF, like stressful conditions, which may change the condition and fitness of exposed individuals, disrupt mate selection, and, in consequence, affect the species’ existence.Graphical

Bioacoustics of Tettigoniidae (Insecta, Orthoptera) Distributed in Hakkari (Eastern Anatolia) Province

In this study, the male calling songs of sixteen species belonging to the Tettigoniidae family distributed in Hakkari were recorded in the field studies and bioacoustic analyses were performed. The bioacoustic analysis of two genera (Kurdia and Novadrymadusa) documented first time with present study and in total six species (Bradyporus (Callimenus) latipes, Isophya hakkarica, Kurdia uvarovi, Novadrymadusa karabagi, Psorodonotus hakkari, and Squamiana supericola) were presented first time. The bioacoustic analyses of seven species (Conocephalus (Anisoptera) fuscus, Pezodrymadusa indivisa, Polysarcus zacharovi, Tettigonia armeniaca, Tettigonia caudata, Tettigonia viridissima, and Uvarovistia satunini) were examined for the first time from Hakkari populations. In addition, in this study, the bioacoustic analyses of three species (Apholidoptera kurda, Saga hakkarica, and Uvarovistia zebra) distributed in Hakkari were re-evaluated in this study on new individuals. As a result of the findings, it has been determined that the male calling song of sixteen species belonging to the Tettigoniidae family are species-specific, have a simple calling song type, and morphological species hypotheses are also supported by bioacoustic data (male calling song).

Description of Calling, Courtship and Mating Behaviour of Six Species of the Genus Zyginidia (Auchenorrhyncha: Cicadellidae).

The vibrational communication and mating behaviour of the graminicolous leafhoppers Zyginidia pullula, Z. ribauti, Z. scutellaris, Z. serpentina, Z. sohrab, and Z. biroi were investigated to explain why the first five species hybridize. Z. biroi was used as a control species. All species behaved in the same way and no significant statistical differences were detected with regard to male calls, while female calls and the male courtship song differed in Z. biroi, thus showing that a specific pre-mating isolation mechanism was used by the latter species and the first five ones lacked such a mechanism. In addition, Z. sohrab is missing in Italy, while the other species live allopatrically in Italy, with the only exceptions being Z. serpentina and Z. biroi, which live in Sicily and are often found in sympatry, and Z. scutellaris and Z. biroi, which live in Sardinia. All these species can be distinguished by means of male genital appendages; however, Z. biroi is longer and has a different body colour. The existence of natural hybrids of Z. pullula, Z. ribauti, and Z. scutellaris in the Italian peninsula and their hybridization in the laboratory with Z. serpentina and Z. sohrab require the investigation of possible post-mating reproductive barriers before re-considering their systematic validity.

Differences in male calling song and female mate location behaviour between urban and rural crickets

Abstract Traffic noise is one of the selection pressures of urban habitats. Because noise interferes with acoustic communication, many studies have shown that the temporal structures of acoustic signals change depending on the noise. However, it is often unknown whether the changes are adaptive, such as changes being more easily located by females under noisy conditions. To investigate the phenomena, bend-legged ground crickets (Dianemobius nigrofasciatus) were collected from three urban and three rural habitats and reared in a common garden conditions. Male calling songs and female mate location behaviour of the progeny were measured. Urban males emitted a calling song with a higher dominant frequency and shorter chirp than did rural males. The playback experiment of female response and localization to songs of urban and rural males, controlling for noise, showed that there were no significant effects of the song on the mate location behaviour between urban and rural songs under noisy conditions. Although the song of urban males elicited a faster response of females, the effect was limited. These results indicate the change in song is not adaptive in terms of female choice. Urban females located more quickly to song under noisy conditions. The results suggest adaptive changes in female mating behaviour occur in urban habitats.

Assessment of the acoustic adaptation hypothesis in frogs using large‐scale citizen science data

AbstractAcoustic communication is vital to the survival and fitness of many vertebrates. While successful communication is reliant on acoustic signals reaching an intended receiver and maintaining content fidelity, propagating signals are attenuated by environmental factors such as habitat type. The acoustic adaptation hypothesis (AAH) predicts that the acoustic properties of signals are selected for optimal transmission in the habitats in which they propagate. To date, consistent evidence to support the theory is lacking, but studies have typically been primarily based on localized datasets with small sample sizes. Citizen science is emerging as a potential means to overcome the challenges associated with broad‐scale sampling, allowing us to assess the validity of the AAH in frogs on a continental scale. We analysed the male advertisement calls of 674 individual banjo frogs (Limnodynastes dorsalis, L. dumerilii, L. interioris and L. terraereginae) from across their range, pairing these citizen science data with remotely sensed measures of habitat complexity. While we detected considerable variation in acoustic structure within and among banjo frog species, this was not strongly correlated with habitat complexity. Thus, we found no support for the AAH. However, with our study spanning an area of over 1.7 million km2, we conducted the largest‐scale test of the AAH in frogs to date, contributing to the global understanding of acoustic signal evolution.

Enhancement of Mating Performance of Sterile Males of Melon Fly,<i>Zeugodacus cucurbitae</i> (Coquillett) Through Methoprene and Cue Lure

The male pupae of Melon fly, Zeugodacus cucurbitae were irradiated at 30 Gy of gamma radiation using Cobalt-60 source. Freshly emerged sterile males (30 Gy) were exposed to different regimes of methoprene and yeast hydrolysate as protein source. Sterile males of 10, 12 and 14 days old were exposed to different regimes of cue lure and yeast hydrolysate. Mating parameters such as lek initiation, lek participation, male calling, mating success and female acceptance index (FAI) were recorded. Sterile males of exposed to methoprene and fed with yeast hydrolysate (M+P+) become sexually matured at three days earlier when compare to protein deprived males (M+P-). High percentage of M+P+ males were engaged in lekking and calling behavior. Sterile males treated with methoprene and fed on protein diet had high percentage of matings with female acceptance index (FAI) of 0.8. Sterile males fed on yeast hydrolysate up to 12-days of age and then accessed to cue lure (P+CL+) had greater mating propensity with frequent mating (43.0%) and FAI of 0.84.

The Mouthparts of Female Blood-Feeding Frog-Biting Midges (Corethrellidae, Diptera)

Females of frog-biting midges (Corethrellidae) obtain their blood meals from male calling frogs. While the morphology of the feeding apparatus is well studied in hematophagous Diptera that impact humans, frog-biting midges have received far less attention. We provide a detailed micromorphological examination of the piercing blood-sucking proboscis and maxillary palpus in three Corethrella species using scanning electron microscopy and histological semi-thin sectioning. We also compare the sensilla found on the proboscis tip and the palpus of Corethrella with other piercing blood-sucking Diptera. Corethrella spp. have a proboscis length of about 135 µm, equipped with delicate mandibular piercing structures composing the food canal together with the labrum and hypopharynx. Their proboscis composition is plesiomorphic and more similar to other short-proboscid hematophagous Culicomorpha (e.g., Simuliidae), in contrast to the phylogenetically more closely related long-proboscid Culicidae. As in other short-proboscid taxa, the salivary canal in Corethrella spp. transitions into an open salivary groove with one mandible forming a seal, whereas in Culicidae the salivary canal is closed until the tip of the proboscis. We discuss the possible functional constraints of very short, piercing blood-sucking proboscises (e.g., dimensions of host blood cells) that may limit the size of the food canal.

Integrated taxonomy of the genus Atlanticus Scudder, 1894 in East China and re-evaluation of morphological characters of eight species (Orthoptera: Tettigoniidae: Tettigoniinae)

Abstract In previous taxonomic studies, identification of Atlanticus species was mainly based on male morphological features, such as cercus, tenth abdominal tergum and subgenital plate. In this study, we systematically revise eight Atlanticus species (61 individuals) in East China. We sequence COI genes of all samples for identification, and compare morphologies and male calling songs. The classification based on male cerci, calling songs, and COI genes is consistent. In contrast, the morphologies of male tenth abdominal tergum and subgenital plate varied among species. In addition, we regard A. jiangyei Liu, Wang & Cheng, 2016 as a junior synonym of A. pieli Tinkham, 1941, and A. helleri Liu, Wang & Cheng, 2016 as a junior synonym of A. kiangsu Ramme, 1939.

The taxonomy and bioacoustics of the elusive crickets from the genus Pendleburyella Chopard, 1969 (Gryllidae: Pentacentrinae).

The taxonomy of poorly known crickets from the genus Pendleburyella Chopard, 1969 (Gryllidae, Pentacentrinae) is reviewed. The type specimens of described species were re-located and re-examined. Based on more recent collections, we describe two new species: Pendleburyella eirmosa sp. nov. and Pendleburyella pimela sp. nov., from Brunei Darussalam and Singapore respectively. The new material also allowed us to examine the male genitalia and describe the male calling song of the genus for the first time.