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Advertisement calls are the main communication form of anurans, and other individuals can use it to evaluate several aspects of the calling individual. In this context, environmental disturbances, such as traffic noise, can potentially affect this recognition. Therefore, this study aims to evaluate the response of Aplastodiscus leucopygius to traffic noise in a fragment of Atlantic Forest within the city of São Paulo. The experimentation consisted of recording the calling individual previously, during and after an exposure to urban noise. After that, individuals were measured to evaluate the Scaled Mass Index (SMI), and individual and environmental temperatures were taken. Also, considering that individuals of this species present harmonic shifting, we tried to evaluate which factors (individual, acoustic, or environmental) are associated with this phenomenon. We observed that the individuals showed an increase in call activity after exposure to traffic noise, but none of the evaluated aspects here could explain the harmonic shifting in their calls. Considering that this increasing on call activity also means an increasing of individual’s expense of energy, traffic noise is potentially harmful to the communication of A. leucopygius and, consequently, to its permanence in the site.

Night-time light can have profound ecological effects, even when the source is natural moonlight. The impacts of light can, however, vary substantially by taxon, habitat and geographical region. We used a custom machine learning model built with the Python package Koogu to investigate the in situ effects of moonlight on the calling activity of neotropical forest katydids over multiple years. We prioritised species with calls that were commonly detected in human annotated data, enabling us to evaluate model performance. We focused on eight species of katydids that the model identified with high precision (generally greater than 0.90) and moderate-to-high recall (minimum 0.35), ensuring that detections were generally correct and that many calls were detected. These results suggest that moonlight has modest effects on the amount of calling, with the magnitude and direction of effect varying by species: half of the species showed positive effects of light and half showed negative. These findings emphasize the importance of understanding natural history for anticipating how biological communities respond to moonlight. The methods applied in this project highlight the emerging opportunities for evaluating large quantities of data with machine learning models to address ecological questions over space and time. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.

The vocal activity of males, crucial for successfully mating in many amphibian species, could differ according to different biotic or abiotic factors. In populations living in urbanized areas, calling activity patterns may deviate significantly from their typical patterns in natural environments. Using passive acoustic monitoring during one breeding season, we assessed the calling activity of three rural and three urban populations of Bufotes viridis to consider the effect of the contrasting habitats on breeding phenology. We assessed the relationship between calling activity, i.e., the number of positive minutes per site, and three environmental cues (precipitation, air temperature, and seasonality) revealed air temperature as the main factor affecting species vocalization, which had a negative effect on calling activity. We noted a deviation from the decreasing call activity pattern during the late breeding season in two urban sites in June and July when calling was notably increased, probably reflecting human intervention in the breeding habitats. [ABSTRACT FROM AUTHOR]

Advertisement calls are the main communication form of anurans, and other individuals can use it to evaluate several aspects of the calling individual. In this context, environmental disturbances, such as traffic noise, can potentially affect this recognition. Therefore, this study aims to evaluate the response of Aplastodiscus leucopygius to traffic noise in a fragment of Atlantic Forest within the city of São Paulo. The experimentation consisted of recording the calling individual previously, during and after an exposure to urban noise. After that, individuals were measured to evaluate the Scaled Mass Index (SMI), and individual and environmental temperatures were taken. Also, considering that individuals of this species present harmonic shifting, we tried to evaluate which factors (individual, acoustic, or environmental) are associated with this phenomenon. We observed that the individuals showed an increase in call activity after exposure to traffic noise, but none of the evaluated aspects here could explain the harmonic shifting in their calls. Considering that this increasing on call activity also means an increasing of individual's expense of energy, traffic noise is potentially harmful to the communication of A. leucopygius and, consequently, to its permanence in the site. [ABSTRACT FROM AUTHOR]

Insects are an integral part of terrestrial ecosystems, but while they are ubiquitous, they can be difficult to census. Passive acoustic recording can provide detailed information on the spatial and temporal distribution of sound-producing insects. We placed recording devices in the forest canopy on Barro Colorado Island in Panamá and identified katydid calls in recordings to assess what species were present, in which seasons they were signaling, and how often they called. Soundscape recordings were collected at a height of 24 m in two replicate sites, sampled at three time-windows per night across five months, spanning both wet and dry seasons. Katydid calls were commonly detected in recordings, but the call repetition rates of many species were quite low, consistent with data from focal recordings of individual insects where calls were also repeated rarely. The soundscape recordings contained 6,789 calls with visible pulse structure. Of these calls, we identified 4,371 to species with the remainder representing calls that could not be identified to species. The identified calls corresponded to 24 species, with 15 of these species detected at both replicate sites. Katydid calls were detected throughout the night. Most species were detected at all three time points in the night, although some species called more just after dusk and just before dawn. The annotated dataset provided here serves as an archival sample of the species diversity and number of calls present in the forest canopy of Barro Colorado Island, Panama. These hand-annotated data will also be key for evaluating automated approaches to detecting and classifying insect calls. In changing forests and with declining insect populations, consistent approaches to insect sampling will be key for generating interpretable and actionable data.

Birds generally produce vocalisations in specific daily temporal windows. Describing diel-calling activity patterns along with taxonomic group and guild membership increase the knowledge about potential factors shaping the behaviour of these animals. This information is also highly relevant for the enhancement of monitoring plans for conservation. We performed a passive acoustic monitoring to describe the diel calling activity patterns of a bird assemblage within the Valdivian temperate rainforest, associating the patterns to taxonomic group and diet guild, and also aiming to contribute to the enhancement of ecological monitoring within this biodiversity hotspot. Our results indicate that high richness levels are detected around sunrise and sunset. Also, within the bird assemblage studied, most birds show diurnal vocal activity, among which several were also active during crepuscular periods, and only two species had nocturnal vocal activity. Among diurnal birds with enough number of detections to perform a detailed description of diel calling patterns, our results did not show clear trends considering diet guild or taxonomic group. We expect that this information encourages future research to increase the understanding on the factors influencing vocal activity patterns, as well as population and community trends from this biodiversity hotspot. [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.

The presence of localized artificial light at night (or ALAN) drastically changes the landscape for organisms by providing areas of darkness and light within an area that was once only dark. This change can influence the behaviors of organisms in many ways. One such behavior is bird song. Many studies have examined how ALAN influences diurnal bird song, but few have examined its influence on nocturnal birds. We examined the influence of lunar illumination and localized artificial light on the calling behavior of the nocturnal Common Poorwill ( Phalaenoptilus nuttallii; hereafter poorwills). To do so, we erected artificial light stations in poorwill territories and then conducted point count surveys at these stations to count poorwill calls with the lights turned on and off. We hypothesized that artificial light would have a similar effect to lunar illumination, and we would see an increase in calling when the lights were on. However, the results we obtained were mixed. We found there was no significant effect of artificial light on calling rate and, as expected, a strong positive effect of moonlight. Surprisingly, however, there was a negative effect of the interaction between moonlight and artificial light, with birds calling less when artificial light was on during nights with high lunar illumination. One possible reason for this result is increased visibility leading to increased predation risk under high levels of ambient illumination.

Background Many factors can influence circadian rhythms in animals. For acoustically communicating species, both abiotic cues (such as light and temperature) and biotic cues (such as the activity of other animals), can influence the timing of signalling activity. Here we compare the 24-h singing activity of the cricket Lebinthus luae in the laboratory and field to assess whether the presence of other singing insects influences circadian rhythm. Methods Acoustic monitors were placed in four localities in Singapore and the number of L. luae calls were counted for 10 min of each hour. Individuals from the same localities were captured and recorded in the laboratory in silence but with similar abiotic conditions (temperature and light cycle) as they experience in the field, and the number of calls over 24 h was quantified. Results The 24-h pattern of L. luae singing was not significantly different between laboratory and field recordings. Singing activity peaked in the morning, with a secondary peak in the afternoon and a smaller peak at night. In the field, L. luae sang in the same locations and at the same time as diurnally singing cicadas, suggesting that the sympatric cicada chorus did not affect the circadian rhythm of communication in this species. Acoustic niche partitioning could potentially explain the ability of this cricket to call alongside cicadas: L. luae sings at higher frequencies than sympatric cicadas, unlike nocturnally singing cricket species that overlap with cicadas in frequency.

Amphibians are the most endangered class of vertebrate on Earth. Knowledge of their ecology is crucial to their conservation; however, many species have received scant attention from researchers, particularly in regions that are difficult to access or when traditional monitoring methods are impractical. In recent years, technological advancements in environmental audio collection techniques and signal detection algorithms (i.e., call recognition) have created a new set of tools for examining the ecology of amphibians. This study utilises these recent technological advancements to examine the calling phenology of a poorly known Australian mountain frog (Philoria kundagungan). Audio recordings and meteorological data were collected from six localities across the species range, with recordings made every hour for ten minutes between July 2016 and March 2018. We developed an audio recognition algorithm that detected over 1.8 million P. kundagungan calls in 8760 h of audio recordings with a true positive rate of 95%. Our results suggest that calling activity was driven by substrate temperature and precipitation, which has potential consequences for the species as the climate warms and seasonal precipitation patterns shift under climate change. With this detailed knowledge of P. kundagungan calling phenology, this difficult-to-find species will now be more reliably detected, removing a barrier that has hindered efforts to study and conserve this species.

Bioacoustics is an effective way of recording detailed data during population surveys and monitoring. In the present study, we used an automated digital recorder (ADR) to describe the temporal variation in the calling activity of Scinax fuscomarginatus (Lutz, 1925) in central Brazil. We also evaluated the role of climatic variables (air temperature and precipitation) on calling activity by using a Generalized Additive Model (GAM). We conducted the recordings at five ponds in the Cerrado savanna of Rio Verde Municipality, in Goiás state between November 2013 and October 2014. The analysis of the 43.2 hours of acoustic recording showed that S. fuscomarginatus has a prolonged breeding pattern. The ADR provides a fine-scale description of the nocturnal calling pattern, as well as the oscillations between the rainy and dry seasons. The results of the analytical model also indicate that calling patterns were related to minimum (but not maximum) air temperatures and precipitation, which may be related to their reproductive and thermoregulatory requirements. Based on these findings, we conclude that the ADR method has potentially valuable applications for the collection of data on the natural history of anuran species, as well as supplying important insights for conservation initiatives.

Frogs play an important role in ecological systems, while frog species across the globe are threatened and declining. Therefore, it is valuable to estimate the frog population based on an intelligent computer system. Due to the success of deep learning (DL) in various pattern recognition tasks, previous studies have used DL-based methods for frog call analysis. However, the performance of DL-based systems is highly affected by their input (feature representation). In this study, we develop a frog calling activity detection system for continuous field recordings using a light convolutional neural network (CNN) with multi-view spectrograms. To be specific, a sliding window is first applied to continuous recordings for obtaining audio segments with a fixed duration. Then, the background noise is filtered out. Next, a multi-view spectrogram is used for characterizing those segments, which has more distinctive information than a single-view spectrogram. Finally, a lightweight CNN model is used for the detection of frog calling activity with a twin loss, where different train and test sets are used to validate the model’s robustness. Our experimental results indicate that the highest macro F1-score was 99.6 ± 0.2 and 96.4 ± 2.0 using 2016 and 2017 as the train data respectively, where CNN-GAP is used as the model with multi-view spectrogram as the input.

Abstract Both sexes of Indian weta Gryllacropsis sp. communicate acoustically. Females lack an external ovipositor making it difficult to differentiate between the sexes in the field. There is limited ecological information on the species as it is found high up on the trunks of evergreen trees, well camouflaged, and active only at night. The present study was conducted to gain ecological information on this little known yet intriguing species. We tested the hypotheses that (a) calling activity of Indian weta is uniformly distributed throughout the year and (b) there is no difference in morphometric measurements between the sexes. The study was conducted in Bhagwan Mahavir Wildlife Sanctuary and Mollem National Park, Goa, India. Visual scanning of tree trunks followed by vegetation sampling, psychoacoustic sampling, and morphometric analyses was carried out. Resource selection function values, obtained for a total of 52 tree species from 1984 individuals, were less than 0.1 for all plant species indicating no preference by the wetas. Peak calling activity was observed in the month of November (Rayleigh's test, Z = 7.90, p

Ecological interactions, including competition, predation, and environmental conditions, may significantly impact acoustic signalling behaviour. Here we characterise nocturnal signalling patterns in the bladder grasshopper Bullacris unicolor and relate this to biotic and abiotic factors, thus providing insights into ecological drivers of acoustic signalling behaviour. Passive acoustic recorders monitored nocturnal calling activity of the focal species, competitors, and predatory bats across the distribution of B. unicolor. Results indicate that B. unicolor calls preferentially at certain times of the night, but that peak activity period varies across the geographic range. There was a strong relationship between B. unicolor activity and bat activity. Bullacris unicolor populations further north showed an overall avoidance of bat echolocation call period, whereas further south an overlapping of call periods between B. unicolor and bat echolocation was observed. Bats at northern sites showed a distinct activity period early in the night and B. unicolor may thus reduce predation risk by shifting signalling activity to later in the night. In contrast, bats were active throughout the night at southern sites and B. unicolor did not delay calling activity in this region of its distribution, although the species did shift signalling slightly to reduce peak overlap with co-existing pneumorid species. [ABSTRACT FROM AUTHOR]

Amphibians are the most endangered class of vertebrate on Earth. Knowledge of their ecology is crucial to their conservation; however, many species have received scant attention from researchers, particularly in regions that are difficult to access or when traditional monitoring methods are impractical. In recent years, technological advancements in environmental audio collection techniques and signal detection algorithms (i.e., call recognition) have created a new set of tools for examining the ecology of amphibians. This study utilises these recent technological advancements to examine the calling phenology of a poorly known Australian mountain frog (Philoria kundagungan). Audio recordings and meteorological data were collected from six localities across the species range, with recordings made every hour for ten minutes between July 2016 and March 2018. We developed an audio recognition algorithm that detected over 1.8 million P. kundagungan calls in 8760 h of audio recordings with a true positive rate of 95%. Our results suggest that calling activity was driven by substrate temperature and precipitation, which has potential consequences for the species as the climate warms and seasonal precipitation patterns shift under climate change. With this detailed knowledge of P. kundagungan calling phenology, this difficult-to-find species will now be more reliably detected, removing a barrier that has hindered efforts to study and conserve this species. [ABSTRACT FROM AUTHOR]

The quantitative understanding of human behavior is a key issue in modern science. Recently, inhomogeneous human activities have been described by bursts (consecutive activities separated by long periods of inactivity) and characterized by fat-tailed inter-event time (interval between two activities) distributions. However, the dynamics between number of activities and activity duration are still unclear. In this study, we analyzed 133 million toll-free call records from China to study the dynamics between call frequency and call duration. We confirmed that both call frequency and call duration exhibit circadian cycles and weekly cycles. By analyzing intraday patterns of these two metrics, we found the opposite volatility and clustered distributions. Results of clustering analysis showed that calling activity to toll-free numbers can be clustered into four clusters. In the "Work" cluster, the distribution of call duration was significantly different from that in the other clusters. The corresponding time of "Work" cluster was much shorter than estimates based on common sense. Intraday patterns and clustering results showed that both call frequency and call duration are primarily related to circadian cycles, the nature of human beings, and that work is a secondary factor that affects these variables. Moreover, we found a strong positive correlation between call frequency and call duration, as well as polarization of joint probability. The polarization indicates two extremes in inhomogeneous calling activity to toll-free numbers, i.e., either people are very busy or very idle. The empirical probability of the extreme was approximately four times that of random probability. Our findings may have great usage for studying the dynamics of inhomogeneous human behavior.

Data were collected using multimodal monitoring technologies pairing sound recorders with time-lapse camera systems. In the spring of 2015, 2016, and 2017, sound recordings and imagery were collected at a wet meadow and forested slough in the Central Platte River Valley of Nebraska. Boreal chorus frog (Pseudacris maculata) calling activity was obtained from analysing sound recordings. Habitat metrics including vegetation phenology and wet meadow hydropattern were derived from image analysis. This dataset can be used to assess phenology, anuran vocalization activity, and environmental change, as well as to further understanding of wetland ecology. Data are co-submitted with manuscript Brinley Buckley, E. M., Gottesman, B. L., Caven, A. J., Harner, M. J., and Pijanowski, B. C., Assessing ecological and environmental influences on Boreal Chorus Frog (Pseudacris maculata) spring calling phenology using multimodal passive monitoring technologies. Ecological Indicators (In Press).

Anuran calling activity is linked to adequate environmental conditions, especially relative humidity, temperature, and rainfall. Consequently, the breeding season is frequently concomitant to the rainy season for most anuran species. This applies in particular to species that reproduce in temporary water bodies, such as our focal species Leptodactylus flavopictus. We assessed the daily and annual calling activity of L. flavopictus through passive acoustic monitoring during a one-year period at Reserva Betary, southeastern Brazil. We redescribe its advertisement call and tadpole, adding details previously unavailable. Adults of L. flavopictus presented seasonal activity, with calls being detected mostly between August and December. The most intense calling activity (in terms of greater calling rates) was detected during spring between October and November. Calling activity was predominantly nocturnal, with an increase of call rates soon after sunset, peaking about 6 hours after sunset. The advertisement call of L. flavopictus is a short, non-pulsed single, note, low pitched (280-680 Hz), and contains harmonics. The tadpole presented morphological traits similar to those of other leptodactylids from temporary ponds, such as L. vastus, for example. The presence of keratinized mouthparts, the shape of labial tooth, and a simple internal oral morphology suggest that this species is at least facultatively carnivorous. During this study, we collected more than 200 hours of soundscape recordings, which included vocalizations of other animals (as birds, other frogs, and insects) that may be used for future community ecology research. We, therefore, reinforce the use of passive acoustic monitoring for studies on anuran behaviour, and the inclusion of advertisement calls and tadpole descriptions in taxonomic and systematic studies, as these features have shown to be important in elucidating questions on anuran evolution. [ABSTRACT FROM AUTHOR]

Background: Many factors can influence circadian rhythms in animals. For acoustically communicating species, both abiotic cues (such as light and temperature) and biotic cues (such as the activity of other animals), can influence the timing of signalling activity. Here we compare the 24-h singing activity of the cricket Lebinthus luae in the laboratory and field to assess whether the presence of other singing insects influences circadian rhythm., Methods: Acoustic monitors were placed in four localities in Singapore and the number of L. luae calls were counted for 10 min of each hour. Individuals from the same localities were captured and recorded in the laboratory in silence but with similar abiotic conditions (temperature and light cycle) as they experience in the field, and the number of calls over 24 h was quantified., Results: The 24-h pattern of L. luae singing was not significantly different between laboratory and field recordings. Singing activity peaked in the morning, with a secondary peak in the afternoon and a smaller peak at night. In the field, L. luae sang in the same locations and at the same time as diurnally singing cicadas, suggesting that the sympatric cicada chorus did not affect the circadian rhythm of communication in this species. Acoustic niche partitioning could potentially explain the ability of this cricket to call alongside cicadas: L. luae sings at higher frequencies than sympatric cicadas, unlike nocturnally singing cricket species that overlap with cicadas in frequency., Competing Interests: Tony Robillard is an Academic Editor for PeerJ., (© 2023 Tan et al.)