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Simple Summary: Male anurans attract conspecific females for reproduction by giving advertisement calls. As calling implies high energetic costs, theory predicts that in mixed-species assemblages call features differ among species to reduce acoustic interference. Each species occupies a distinct acoustic niche in the soundscape. In equatorial wetlands water bodies for reproduction are available all over the year, therefore, we expect that diel and seasonal partitioning of acoustic space should be less important than differences in call structure to reduce competition and niche overlap. Additionally, acoustic communities should be species-saturated. We tested these predictions in four communities at 2546–3188 m a.s.l. in the Volcanoes National Park, Rwanda. Using automated recording devices from September 2019 to March 2020, we obtained an extensive dataset on call activity. The communities included 4–6 species, depending on the wetland structure, with a common stock of three species (Hyperolius castaneus, H. glandicolor, Leptopelis kivuensis). Independent of elevation, niche breadth for call features was similar and overlap reduced by partitioning the frequency range used. The diel and seasonal niche breadth of specific call activity varied according to the local temperature regime at different altitudes. We conclude that stochastic niche theory describes accurately the processes shaping equatorial highland communities. The soundscape is a complex arrangement of sounds originating from animals and the environment. It is considered a reliable proxy for ecosystem niche structure at the community level. Acoustic communities of anuran species include advertising males, which compete in acoustic space for conspecific females. Stochastic niche theory predicts that all local niches are occupied, and the acoustic community is species-saturated. Acoustic niches, which include the spectral and temporal call structure and diel and seasonal patterns of call activity, are of similar breadth with small overlap. We tested these predictions in four communities inhabiting pristine wetlands at 2546–3188 m a.s.l. in the Volcanoes National Park, Rwanda. We sampled 74 days of hourly 5 min recordings of the local soundscape (September 2019–March 2020) using passive automated monitoring devices (Songmeter SM4). We identified species based on the advertisement call features and measured call activity as calls per minute. The communities included 4–6, species depending on wetland structure, with a shared stock of three species (Hyperolius castaneus, H. glandicolor, Leptopelis kivuensis). Independent of elevation, niche breadth for call features was similar among species and overlap reduced by partitioning the frequency range used. The diel and seasonal niche breadth of specific call activity varied according to the local temperature regime at different altitudes representing the variable part of the acoustic niche. We conclude that communities are indeed species-saturated and acoustic niches differ primarily by the fixed call features remaining locally adaptable by the modulation of the call activity pattern, corroborating the predictions of the stochastic niche theory. [ABSTRACT FROM AUTHOR]

The soundscape is a complex arrangement of sounds originating from animals and the environment. It is considered a reliable proxy for ecosystem niche structure at the community level. Acoustic communities of anuran species include advertising males, which compete in acoustic space for conspecific females. Stochastic niche theory predicts that all local niches are occupied, and the acoustic community is species-saturated. Acoustic niches, which include the spectral and temporal call structure and diel and seasonal patterns of call activity, are of similar breadth with small overlap. We tested these predictions in four communities inhabiting pristine wetlands at 2546–3188 m a.s.l. in the Volcanoes National Park, Rwanda. We sampled 74 days of hourly 5 min recordings of the local soundscape (September 2019–March 2020) using passive automated monitoring devices (Songmeter SM4). We identified species based on the advertisement call features and measured call activity as calls per minute. The communities included 4–6, species depending on wetland structure, with a shared stock of three species (Hyperolius castaneus, H. glandicolor, Leptopelis kivuensis). Independent of elevation, niche breadth for call features was similar among species and overlap reduced by partitioning the frequency range used. The diel and seasonal niche breadth of specific call activity varied according to the local temperature regime at different altitudes representing the variable part of the acoustic niche. We conclude that communities are indeed species-saturated and acoustic niches differ primarily by the fixed call features remaining locally adaptable by the modulation of the call activity pattern, corroborating the predictions of the stochastic niche theory.

The influence of abiotic and biotic factors on the temporal pattern of calling and breeding for many temperate anurans is well understood. However, few studies have documented patterns of reproduction in explosive-breeding tropical frogs or incorporated multiple environmental factors in their analyses, especially across multiple breeding seasons. We combine long-term natural history observations and automated data collection methods with boosted regression tree (BRT) analysis to determine the phenology and determinants of explosive breeding in the gliding treefrog, Agalychnis spurrelli. We monitored breeding for a total of 418 days across three breeding seasons and determined the relative importance of several environmental factors on the probability of calling and breeding activity. Our study population of A. spurrelli on Costa Rica's Osa Peninsula forms breeding aggregations up to 11 times per year during 1–2-day long explosive-breeding events, from late May to mid-September. Calling and breeding activity are strongly and positively related to accumulated rainfall during the previous 24 and 48–24 h before, particularly rainfall during the afternoon and evening. Day-of-year, days since breeding occurred, and lunar phase also influence reproductive activity. This study provides the first description and analysis of the phenology and factors that predict explosive breeding in A. spurrelli and illustrates the value of using automated data collection paired with BRTs for the analysis of complex ecological data. La influencia de factores abióticos y bióticos en el patrón temporal de cantos y reproducción de muchos anuros de zonas templadas es bien conocida. Sin embargo, pocos estudios han documentado patrones de reproducción en ranas tropicales, que se reproducen de manera explosiva, o han incorporado múltiples factores ambientales en sus análisis, especialmente a lo largo de múltiples temporadas de reproducción. Combinamos observaciones de historia natural a largo plazo y métodos automatizados de recolectar datos con análisis de árboles de regresión y técnicas de remuestreo ('boosted regression trees', BRT) para determinar la fenología y los determinantes de la reproducción explosiva en la rana planeadora, Agalychnis spurrelli. Monitoreamos la reproducción durante un total de 418 días a través de tres temporadas de reproducción y determinamos la importancia relativa de varios factores ambientales en la probabilidad de cantos y reproducción. Nuestra población de estudio de A. spurrelli en la Península de Osa en Costa Rica forma agregaciones reproductivas hasta 11 veces por año, los eventos de reproducción explosiva tienen 1 a 2 días de duración, desde finales de mayo hasta mediados de septiembre. Los cantos y la reproducción están fuerte y positivamente relacionados con la acumulación de lluvia en las 24 y 48 a 24 horas anteriores, particularmente durante la tarde y la noche. El día del año, los días desde la última reproducción, y la fase lunar también influyen la reproducción. Este estudio es la primera descripción y análisis de la fenología y los factores que predicen la reproducción explosiva en A. spurrelli e ilustra el valor de utilizar la recolección de datos automatizada junto con BRT para el análisis de datos ecológicos complejos. [ABSTRACT FROM AUTHOR]

There is very little information on the diurnal and seasonal patterns of Cuculidae species' calling activity in subtropical areas. In this study, we used passive acoustic monitoring to investigate the diurnal and seasonal patterns of calling activity of seven Cuculidae species at three sites in eastern China's forest over a year. Our results showed that these species exhibited significant diurnal variations except for Cuculus micropterus. Eudynamys scolopaceus and Cuculus saturatus increased their vocal activity at dawn and dusk, whereas the other four species peaked their calling activity in the morning. Five species showed significant seasonal variations with a peak in vocal activities earlier in the season (late May or early June) and a gradual decline after that, except for Clamator coromandus, which displayed two peaks in seasonal calling activity. As for Cuculus micropterus, its calling activity was not significantly related to the season. Our study has provided basic knowledge about the calling patterns of seven Cuculidae species, and based on seasonal changes in vocal activity we propose that the breeding season of these species in east China begins in late May and ends in July. [ABSTRACT FROM AUTHOR]

Amphibian breeding is often linked to environmental cues. Given accelerating global climate change and habitat alteration, it is important to understand how environmental changes may affect male calling activity, the necessary precursor to mating. Here, we investigate the calling phenology and activity of Geocrinia alba, a critically endangered terrestrial‐breeding frog with a highly restricted distribution in southwestern Australia – a region undergoing significant warming and drying. We investigated whether calling periods differed across eight sites during a single breeding season, and the environmental conditions associated with calling activity at the start, peak and end of the calling period. We found consistent and prolonged calling activity over several months of the austral spring, but the length of the calling period varied two‐fold across sites, ranging from 3 to 6 months. Initiation of calling by G. alba was relatively similar across sites and was associated with warmer temperatures and higher soil water potential. However, the end of the calling period varied from October to January and was significantly associated with decreasing soil water potential. Calling only occurred when soils were close to saturation point, between −8 to −11 kPa, and therefore, breeding opportunities were likely also constrained by the length of time that soils were close to saturation. Changes in the regional climate, such as declining winter rainfall, could result in shorter breeding periods and consequently reduced breeding opportunities. More broadly, our study highlights the sensitivity of amphibians, particularly terrestrial‐breeding species, to changes in soil water potential and temperature, and the importance of maintaining suitable hydrological conditions during the breeding period. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The relative influence of climatic and social factors on sex-specific variation in reproductive behaviour remains poorly understood. Here, we examine the influence of multiple climatic cues in combination with a social cue on the reproductive behaviours of males and females in a terrestrial breeding toadlet (Pseudophryne coriacea). Over a 115-day breeding season, arrival patterns of each sex, and male calling activity, were recorded daily, while climatic variables were logged continuously. Multivariate analysis showed that arrival of males at the breeding site, as well as male nightly calling activity, were most strongly influenced by a climatic variable (rainfall). By contrast, female arrival was strongly correlated with a social variable (male calling activity), with abiotic conditions having no influence, other than a moderate influence of lunar phase (lunar illumination). These results suggest that cues used for breeding are sex specific and provide new evidence that combinations of climatic and social cues can be integrated into breeding decisions. [ABSTRACT FROM AUTHOR]

Temporal scale in animal communities is often associated with seasonality, despite the large variation in species activity during a diel cycle. A gap thus remains in understanding the dynamics of short‐term activity in animal communities.Here we assessed calling activity of tropical anurans and addressed how species composition varied during night activity in assemblages along gradients of local and landscape environmental heterogeneity.We investigated 39 anuran assemblages in the Pantanal wetlands (Brazil) with passive acoustic monitoring during the peak of one breeding season, and first determined changes in species composition between night periods (early, mid and late) using two temporal resolutions (1‐ and 3‐hr intervals). Then, we addressed the role of habitat structure (local and landscape heterogeneity variables from field‐based and remote sensing metrics) and ecological context (species richness and phylogenetic relatedness) in determining changes in species composition (a) between night periods and (b) across days.Nocturnal calling activity of anuran assemblages varied more within the 1‐hr resolution than the 3‐hr resolution. Differences in species composition between early‐ and late‐night periods were related to local habitat structure and phylogenetic relatedness, while a low variation in compositional changes across days was associated with low‐heterogeneous landscapes. None of these relationships were observed using the coarser temporal resolution (3 hr).Our findings on the variation of calling activity in tropical anuran assemblages suggest potential trade‐offs mediated by fine‐temporal partitioning. Local and landscape heterogeneity may provide conditions for spatial partitioning, while the relatedness among co‐signalling species provides cues on the ecological overlap of species with similar requirements. These relationships suggest a role of niche dimensional complementarity on the structuring of these anuran assemblages over fine‐temporal scales. We argue that fine‐temporal differences between species in breeding activity can influence the outcome of species interaction and thus, addressing temporal scaling issues can improve our understanding of the dynamics of animal communities. [ABSTRACT FROM AUTHOR]

There is very little information on the diurnal and seasonal patterns of Cuculidae species’ calling activity in subtropical areas. In this study, we used passive acoustic monitoring to investigate the diurnal and seasonal patterns of calling activity of seven Cuculidae species at three sites in eastern China’s forest over a year. Our results showed that these species exhibited significant diurnal variations except for Cuculus micropterus. Eudynamys scolopaceus and Cuculus saturatus increased their vocal activity at dawn and dusk, whereas the other four species peaked their calling activity in the morning. Five species showed significant seasonal variations with a peak in vocal activities earlier in the season (late May or early June) and a gradual decline after that, except for Clamator coromandus, which displayed two peaks in seasonal calling activity. As for Cuculus micropterus, its calling activity was not significantly related to the season. Our study has provided basic knowledge about the calling patterns of seven Cuculidae species, and based on seasonal changes in vocal activity we propose that the breeding season of these species in east China begins in late May and ends in July.

Abstract The reproduction is one of the main events in the life of an organism, and anurans stand out among vertebrates because of the diversity of their reproductive strategies. We studied the reproduction of two syntopic species, Physalaemus aff. albonotatus and P. santafecinus, and comparatively described their reproductive activity pattern, advertisement calls, calling sites, daily calling activity, amplexus behavior, foam nests, and microhabitats in foam nests. In regards to the reproductive activity pattern, both species were defined as prolonged breeders. However, P. santafecinus exhibited a behavior like explosive breeders: it had a faster reproductive response against rains than P. aff. albonotatus. The calling activity was restricted exclusively to night hours in P. santafecinus, whereas P. aff. albonotatus called during both night and day. The advertisement calls of both species showed a rich harmonic structure, and were characterized by a bimodal harmonic dominance. The species differed significantly in microhabitat calling sites, foam nests, and microhabitats in foam nests. Namely, P. santafecinus frequently called and constructed its nests in sites more exposed than those of P. aff. albonotatus. The general differences in reproductive behaviors observed between the species principally agree with their different reproductive activity patterns.

Potoos (Nyctibius spp.) are nocturnal Neotropical canopy-dwelling birds, making them one of the most enigmatic and least known avian families. The Common Potoo (Nyctibius griseus) and the Great Potoo (Nyctibius grandis) are the most widespread species, but little information on their life histories is available. We evaluated the utility of autonomous recording units, coupled with automated signal recognition software, to monitor the calling behavior of both species for the first time over a complete annual cycle at six different sites in the Brazilian Pantanal. Their diel activity was restricted to the night, with higher calling rates after midnight. The breeding season of the Common Potoo, according to seasonal changes in vocal activity, seems to occur between July and November, while the breeding period of the Great Potoo extended from July to December. The reproduction periods proposed for each potoo in this study correspond mainly with the dry season in the study area and are in agreement with the few historical nest site observations from Brazil. The maximum calling activity of both species occurred between 1 and 5 a.m. September was the month with the maximum vocal activity of the Common Potoo, while the Great Potoo was most vocally during October. The vocal activity of neither potoo was related to night temperature. The Great Potoo was more vocally active during nights with high moon illumination. Our results will be useful in future monitoring programs for these species. Acoustic monitoring has proven to be a helpful tool for monitoring the presence and calling seasonality of the Common Potoo and the Great Potoo, mainly due to their naturally low vocal activity rates. Acoustic monitoring should be evaluated and used to increase our knowledge about the ethology and ecology of this enigmatic avian family. [ABSTRACT FROM AUTHOR]

Acoustic monitoring provides the opportunity to study ecological processes that are difficult to assess with traditional surveys. Elachistocleis matogrosso is an anuran species, described in 2010, for which limited biological information is available. This study investigated the calling activity of the species in the north-eastern portion of the Pantanal, Brazil, a wetland area with marked seasonality between the dry and wet seasons. The calling activity of E. matogrosso was monitored using automated digital recorders in combination with automated signal recognition software over two different annual cycles. The species was vocally active only during the wet season (October – April), with a peak in November-December during the 2013–2014 annual cycle and in February-March during the 2015–2016 annual cycle. The peak calling activity occurred at dusk. This species has nocturnal habits and an explosive breeding activity. The detection of the species was intermittent, which suggests that environmental predictors or site-specific conditions might play an important role in species detection. Moreover, this intermittent occupancy indicated that surveys that employ traditional field techniques would likely fail to detect this species. We describe an effective protocol for detecting E. matogrosso with acoustic monitoring, which requires recording during 20 days in February from 17:01 to 05:00. Our procedure would be easy to adapt to other anuran species, and it could be used for investigating new localities and assessing population changes over time. [ABSTRACT FROM AUTHOR]

Fishes communicate acoustically under ecological constraints which may modify or hinder signal transmission and detection and may also be risky. This makes it important to know if and to what degree fishes can modify acoustic signalling when key ecological factors—predation pressure, noise and ambient temperature—vary. This paper reviews short‐time effects of the first two factors; the third has been reviewed recently (Ladich,). Numerous studies have investigated the effects of predators on fish behaviour, but only a few report changes in calling activity when hearing predator calls as demonstrated when fish responded to played‐back dolphin sounds. Furthermore, swimming sounds of schooling fish may affect predators. Our knowledge on adaptations to natural changes in ambient noise, for example caused by wind or migration between quiet and noisier habitats, is limited. Hearing abilities decrease when ambient noise levels increase (termed masking), in particular in taxa possessing enhanced hearing abilities. High natural and anthropogenic noise regimes, for example vessel noise, alter calling activity in the field and laboratory. Increases in sound pressure levels (Lombard effect) and altered temporal call patterns were also observed, but no switches to higher sound frequencies. In summary, effects of predator calls and noise on sound communication are described in fishes, yet sparsely in contrast to songbirds or whales. Major gaps in our knowledge on potential negative effects of noise on acoustic communication call for more detailed investigation because fishes are keystone species in many aquatic habitats and constitute a major source of protein for humans. [ABSTRACT FROM AUTHOR]

Acoustic segregation is a way to reduce competition and allows for species coexistence within anuran communities. Thus, separation in at least one acoustic niche dimension is expected, which also contributes to achieving effective communication among frogs. Here we studied an assemblage of five terrestrial egg-laying anuran species, all in the genus Eleutherodactylus , in a montane rainforest in eastern Cuba. Our aim was to determine if partitioning exists between these species in any dimension (time, signal frequency or space) of the acoustic niche. The studied assemblage had the following characteristics: (1) there was one diurnal species, two species with calling activity throughout the day and two species that call at night; (2) only two species overlapped in call frequencies and most had different calls, both in terms of dominant frequencies and in temporal characteristics; and (3) males of the species that overlapped in vocalizing time or signal frequency used different calling microhabitats or heights. This study provides evidence for the acoustic niche hypothesis in anurans, showing low probabilities of interference in sound communication among these frogs. The five species were separated in at least one of the three acoustic dimensions (calling time, frequency and site) as it occurs in mainland communities with more sympatric species of several genera. Conversely, species in single-genus communities studied in Puerto Rico overlapped completely in calling times. This seems to be due to the higher number of sympatric species at our site. [ABSTRACT FROM AUTHOR]

Abstract: Temperature affects peripheral and central mechanisms of signal production and detection in ectothermic animals. This study reviews for the first time the effects of temperature on acoustic communication in fishes and analyses whether changes in sound properties are coupled to changes in auditory sensitivities. Effects of temperature on sound production have been studied in approximately one dozen families of teleosts. Calling activity increased or was unaffected by temperature, in the latter case probably because seasonal, daily and lunar rhythms also influence mating behaviour and calling. Sound characteristics (pulse repetition rate, fundamental frequency) are positively correlated with temperature if pulses are directly based on sonic muscle contractions. In fishes possessing other sonic mechanisms, the dominant frequency of their pulsatile pectoral sounds may increase as well. Auditory sensitivities were mainly determined in otophysines, which possess enhanced hearing abilities. Studies revealed that hearing increased with temperature, in particular at higher frequencies. We know close to nothing about whether temperature‐dependent changes in sound characteristics are coupled to changes in auditory sensitivity or mate choice. Female midshipman toadfish appear to choose males based on call frequency, which varies with temperature. Future studies need to address several topics: (i) temperature effects on sound production have to be separated from other sources of variation; (ii) effects on hearing need to be studied in many more taxa; (iii) potential negative effects of global warming on acoustic communication (because of temperature coupling) need to be investigated because fish constitute a major source of protein for humans. [ABSTRACT FROM AUTHOR]

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We describe the breeding biology and the advertisement call of the horned leaf-frog, Proceratophrys appendiculata (Günther, 1873) in the Parque Nacional da Serra dos Órgãos, municipality of Teresópolis. The reproductive period of P. appendiculata is short and is associated with the end of the winter and the beginning of the spring, when males call night and day under large rocks in sandy bottom rock streams. The amplexus is axillary and one female laid about 656 viscous eggs. The advertisement call of P. appendiculata is unique among congeners. The call lasts approximately two seconds, with about 85 pulses/call at a rate of 45 pulses/s and frequency around 0.620 kHz. It is one of the longest calls and lowest in dominant frequency. Moreover, the call of P. appendiculata is characterized by the greatest number of pulses so far registered, reaching 129 pulses in a single call.

Temporary pools are important resources for animals that have aquatic stages during their life history, and particularly for those living in dry climate regions. We investigated the breeding activity of an anuran assemblage in a small temporary pond in the Ampijoroa dry forest of Ankarafantsika National Park, northwestern Madagascar, during the first half of the rainy season from 2000 to 2001 and during the entire rainy season and the beginning of the dry season from 2003 to 2004. We also surveyed the anuran fauna of Ampijoroa throughout the long-term research conducted from 1999 to 2014. We estimated the breeding activity based on the calling intensity of male frogs. A total of 12 species of frogs was recorded, and eight out of them were confirmed to breed in the temporary pond. These eight species consisted of five families, including one introduced species. The initiation of calling activity seemed to be affected by rainfall in several species. Five of the eight species ( Ptychadena mascareniensis, Boophis doulioti, Blommersia wittei, Heterixalus luteostriatus and H. tricolor) were considered prolonged breeders, and the other three ( Laliostoma labrosum, Hoplobatrachus tigerinus, and Dyscophus insularis) were considered explosive breeders. Two species ( Mantidactylus ulcerosus and Stumpffia sp.) were not observed to use the temporary pond for their breeding sites. Neither calls nor breeding sites of the remaining two species ( Scaphiophryne calcarata and Mantella ebenaui) were confirmed, although they have been described to breed in stagnant water. This study indicates that temporary ponds in the Ampijoroa forest, which are quite limited in number, provide important habitat for reproduction of frogs, which are living in a harsh environment. [ABSTRACT FROM AUTHOR]

Frogs are immediately associated to their conspicuous vocalizations emitted during the breeding season. Therefore, many scientists were inspired to study their acoustic communication. Nowadays, many types of calls are described and we felt the need of reviewing the terminology currently and historically applied. As a result, we proposed the classification of anuran vocalization into three major categories: reproductive, aggressive, and defensive calls. These categories are subdivided according to the social context of emission mostly reflecting also acoustic differences among call types. Some call types are here proposed to be synonymies of the mostly used and inclusive terms. We also suggest terminologies for basic bioacoustical analyses, mostly applied in call descriptions. Furthermore, we present cases of complex calls, including call gradation. Finally, based on novel data (such as an unusual case of juvenile vocalizations), we discuss situations in which it is difficult to classify call types, reflecting the need of experimental studies. [ABSTRACT FROM AUTHOR]

Amphibian populations have been declining worldwide over the last few decades due to causes like habitat modification, climate change, and emergent diseases.Hyla suweonensis, a treefrog species endemic to Korea, has disappeared from much of its historic distributional range. Past studies reported this species to breed exclusively in man-made rice paddies. This study reports the habitat characteristics of a seminatural site forH. suweonensis. Out of 100 sites whereH. suweonensiswas present, only one was not a rice paddy. This seminatural site was characterized by a network of swamps bordered with forests of willow trees.H. suweonensisindividuals located on willow trees called from 0.2 to 1.50 m above ground at the edge of the forest near the swamps. The seminatural site has a large percentage of rice paddies with a very low percentage of urban areas, a feature consistent with findings of a previous study.H. suweonensiswas found calling with two other amphibian species. Although extracted from a single site, the information from this study is important for the management and the conservation of the species. [ABSTRACT FROM AUTHOR]

Differences in advertisement calls and calling sites are important mechanisms that regulate interactions in anuran assemblages. Individuals might have preferences for ranges of acoustic parameters and calling sites that reduce overlap and ensure coexistence. Herein, acoustic and ecological data were used to investigate the relationships among 12 anurans that co-occur in temporary ponds in the Caatinga, Cabaceiras municipality, Paraíba state, Brazil. Anurans exhibited calling activity correlated with rainfall, but were also spatially dispersed. High overlap levels in calling microhabitats and acoustic parameters were observed, especially among pairs of closely related species. Analysis of null models showed a lack of structure in the spatial and acoustic niche, indicating the lack of detected competition. Results suggest that the calling activity of the species is strongly influenced by rainfall, moreover, the temporal partition appears to ensure coexistence. Finally, strong historical effects were detected in Leiuperinae, Leptodactylidae and in the partition Hylidae–Leptodactyliformes. [ABSTRACT FROM PUBLISHER]

A comparison between localities currently occupied by a species and localities where the species recently underwent local extinction is a powerful way to understand the causes of population decline. Two closely related treefrog species occur in the Republic of Korea: Hyla japonica , which is distributed widely throughout northeastern Asia, and H. suweonensis , which occurs sympatrically on a narrow strip of the western coastal plains in Korea. Males of both species produce species-specific advertisement calls. To determine the spatiotemporal distributions of H. suweonensis and H. japonica during their breeding seasons, auditory monitoring was conducted in 70 localities throughout the historic range of H. suweonensis . A group of volunteers conducted the monitoring, supplemented with call recordings for validation. The endangered H. suweonensis was found in only 14 of 70 localities, designated as syntopic, whereas H. japonica occurred in all 70 localities. The calling activity of H. japonica was constantly vigorous throughout the study period, whereas the calling activity of H. suweonensis was generally weak. The analysis of binary logistic regression identified the percentage of rice-paddy field as the significant variable. The syntopic localities had much higher percentages of the rice-paddy field than the non-syntopic localities did. Localities where the rice-paddy fields are fragmented and isolated by commercial and residential complexes are not likely to harbor the H. suweonensis populations. The spatiotemporal distributions of the two treefrog species throughout the breeding seasons confirm that H. suweonensis is indeed rare and requires swift and decisive measures, including the establishment of protected areas. [ABSTRACT FROM AUTHOR]

Environmental and social factors are critical to determine the timing and duration of lekking behavior since they provide species with signs to maximize benefits over costs in sexual displays. However, these factors have rarely been studied under different environmental conditions, and thus, it remains unclear whether exogenous factors affecting group displays show a general species-specific pattern or whether they are population-specific. Using audio-trapping techniques, we compared factors influencing the daily occurrence and duration of lekking behavior in two populations of Hyla molleri and two populations of Hyla meridionalis located at the thermal extremes (coldest vs. hottest) of their Iberian distribution range. From 12,240 hourly recordings over one season, multimodel inference revealed that the major determinants of chorus occurrence were similar between populations and species (i.e., chorus size the previous day, daytime air temperature, relative humidity, and barometric pressure), and accounted for 51-79 % of its deviance. In contrast, the major determinants of chorus duration differed between populations and species (i.e., chorus size, number of day, and air temperature and relative humidity at the onset of the chorus), and accounted for 38-69 % of its variance. Our findings suggest that the decision making related to lek attendance is environment-dependent, takes place at time between lekking events, and is associated with exogenous factors that may be both stable across species ranges and population-specific when populations are under different climatic conditions. This intraspecific variation might be underlain by plasticity mechanisms providing tree frogs with means to cope with changing environments. Moreover, social facilitation related to male-male acoustic competition seems to play a relevant role on the daily time invested by males in lek attendance. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Conservation Science is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The phenology of calling activity and reproduction of a neotropical anuran community in French Guiana was studied during one rainy season. We investigated the correlation between calling activity, rainfall, temperature and water level in two ponds and recorded the occurrence of tadpoles of pond-breeding species. The study site contained 31 calling frog species, which were divided into groups according to reproductive mode. Increased rainfall was associated with increased reproductive activity in all groups, but temporal patterns in calling activity varied significantly between groups. Species with aquatic oviposition exhibited sporadic acoustic activity, aggregating into explosive breeding events following heavy rainfall. Species laying eggs in foam nests had the peak of calling activity at the start of the rainy season. Taxa with embryonic development on vegetation called mainly from middle to late wet season, being the only group which showed a significant correlation of calling with increasing water level. Dendrobatids with terrestrial oviposition and subsequent parental tadpole transportation were continuously active. Species with direct development or with non-feeding larvae were mainly active at the beginning of the rainy season. It is concluded that phenologies of calling activity in South American tropical anuran species are strongly influenced by abiotic factors like rainfall and availability of breeding sites. The temporal limitation of the rainy season forces species to adjust calling and reproductive activity according to their reproductive modes. [ABSTRACT FROM PUBLISHER]

Male Teleogryllus oceanicus (Orthoptera: Gryllidae) produce a conspicuous calling song to attract females. In some populations, the song also attracts the phonotactic parasitoid fly Ormia ochracea (Diptera: Tachinidae). I examined the factors affecting calling song by characterizing the calling behavior of caged crickets from an area where the fly occurs. Calling activity (proportion of time spent calling) was repeatable and a significant predictor of female attraction. However, calling activity in the parasitized population was lower than in an unparasitized Moorea population (Orsak, 1988), suggesting a compromise between high activity to attract females and low activity to avoid flies. Calling activity peaked simultaneously with fly searching, so crickets did not shift to calling when the fly is less active. Males harboring larvae did not call less than unparasitized males; however, a more controlled study of the effects of parasitization on calling behavior is needed to evaluate this result. The results are discussed in the context of other studies of the evolutionary consequences of sexual and natural selection on cricket calling behavior. [ABSTRACT FROM AUTHOR]

Both fat and glycogen are present in abundance in the larynx muscles of anurans. To clarify their role, the Musculus dilatator laryngis of the male fire-bellied toad, Bombina bombina was studied. In untreated males, the mean fat content of this larynx muscle was 14%; the muscle contained glycogen amounting to 57% of that measured in the liver tissue of the same animal. After thirteen days of continual calling activity induced by administration of a gonadotropin, the fat content fell to 6%, the glycogen to 34%. The fat content was essentially unchanged (13%) by four hours of electrical stimulation of the muscle; the glycogen content, however, had fallen to 42% after this treatment. Neither component was altered in amount by castration, the fat content being about 13% and that of glycogen, 52%. Nor did treatment with gonadotropic hormone reduce either the fat content (13%) or the amount of glycogen (59%). From these results it was concluded that fats represent a direct source of energy for the larynx muscles, which is used up gradually over long periods of calling. The glycogen in these muscles, on the other hand, is a short-term store sufficient to supply energy for only a few hours of calling activity. [ABSTRACT FROM AUTHOR]

In the recent decades, calling activities have been studied from different perspectives in social physics field. In diverse studies, call frequencies and call durations have been widely used to quantify calling activity. However, they have been rarely studied. In this work, long-term correlations as well as the multifractality of toll-free call frequency (TFCF) and toll-free call duration (TFCD) time series were investigated with multifractal detrended fluctuation analysis (MFDFA). The results show that these two time series have a similar crossover, which is approximately 36 h, and they have different long-term correlations as well as sophisticated multifractality below and above the crossover. The TFCF time series below the crossover is non-stationary and small fluctuations contribute more to its strong multifractality than large fluctuations. The TFCF time series above the crossover is stationary with long-term anti-correlation and its weak multifractality is only caused by small fluctuations. The TFCD time series below the crossover is non-stationary and large fluctuations contribute more to its strong multifractality than small fluctuations. The TFCD time series above the crossover is stationary with long-term correlation and its weak multifractality is mainly caused by small fluctuations. Moreover, we found that the multifractality of the TFCF time series is primarily caused by correlations, but that of the TFCD time series is caused by a combination of correlations and broad distribution of data. We also discussed the possible factors in the sophisticated multifractality with comparative analysis. • TFCF and TFCD time series have a similar crossover (36 h).. • For blow the crossover, they have strong multifractality with opposite sided multifractal spectra. • For above the crossover, they have weak multifractality and inverse long-term correlations. • Sources of multifractality have been found. [ABSTRACT FROM AUTHOR]

Sound communication is affected by ambient temperature in ectothermic animals including fishes. The present study examines the effects of temperature on acoustic signaling in a fish species possessing two different sound-generating mechanisms. The Amazonian Pictus catfish Pimelodus pictus produces low-frequency harmonic sounds (swimbladder drumming muscles) and high-frequency stridulation sounds (rubbing pectoral fin spines in the pectoral girdle). Sounds of 15 juveniles were recorded when hand-held after three weeks of acclimation at 30 °C, 22 °C and again 30 °C. The following sound characteristics were investigated: calling activity, sound duration, fundamental frequency of drumming sounds and dominant frequency of stridulation sounds. The number of both sound types produced within the first minute of experiments did not change with temperature. In contrast, sound duration was significantly shorter at 30 °C than at 22 °C (drumming: 78–560 ms; stridulation: 23–96 ms). The fundamental frequency of drumming sounds and thus the drumming muscle contraction rate varied from 127 Hz to 242 Hz and increased with temperature. The dominant frequency of broadband stridulation sounds ranged from 1.67 kHz to 3.39 kHz and was unaffected by temperature changes. Our data demonstrate that temperature affects acoustic signaling in P. pictus , although the changes differed between sound characteristics and sound type. The effects vary from no change in calling activity and dominant frequency, to an increase in fundamental frequency and shortened duration of both sound types. Together with the known effects of temperature on hearing in the Pictus cat, the present results indicate that global warming may affect acoustic communication in fishes. Unlabelled Image • Acoustic signaling in fishes is variously influenced by ambient temperature. • Pictus catfish emit low-frequency drumming and high-frequency stridulation sounds. • Number of emitted drumming and stridulation sounds did not change with temperature. • Temporal sound characteristics were similarly, spectral properties differently affected. • Temperature effects depend on sound characteristic and sonic mechanism in Pictus cats. [ABSTRACT FROM AUTHOR]