Titel Deelnemers "Korte inhoud" "The use of bioacoustics in anuran taxonomy: theory, terminology, methods and recommendations for best practice" "Ariel Rodriguez, Philippe Kok, Frank Glaw, Célio Haddad, Mark-Oliver Rödel, Miguel Vences" "Vocalizations of anuran amphibians have received much attention in studies of behavioral ecology and physiology, but also provide informative characters for identifying and delimiting species. We here review the terminology and variation of frog calls from a perspective of integrative taxonomy, and provide hands-on protocols for recording, analyzing, comparing, interpreting and describing these sounds. Our focus is on advertisement calls, which serve as premating isolation mechanisms and, therefore, convey important taxonomic information. We provide recommendations for terminology of frog vocalizations, with call, note and pulse being the fundamental subunits to be used in descriptions and comparisons. However, due to the complexity and diversity of these signals, an unequivocal application of the terms call and note can be challenging. We therefore provide two coherent concepts that either follow a note-centered approach (defining uninterrupted units of sound as notes, and their entirety as call) or a call-centered approach (defining uninterrupted units as call whenever they are separated by long silent intervals) in terminology. Based on surveys of literature, we show that numerous call traits can be highly variable within and between individuals of one species. Despite idiosyncrasies of species and higher taxa, the duration of calls or notes, pulse rate within notes, and number of pulses per note appear to be more static within individuals and somewhat less affected by temperature. Therefore, these variables might often be preferable as tax- onomic characters over call rate or note rate, which are heavily influenced by various factors. Dominant frequency is also comparatively static and only weakly affected by temperature, but depends strongly on body size. As with other taxonomic characters, strong call divergence is typically indicative of species-level differences, whereas call similarities of two populations are no evidence for them being conspecific. Taxonomic conclusions can especially be drawn when the general advertisement call structure of two candidate species is radically different and qualitative call differences are thus observed. On the other hand, quantitative differences in call traits might substantially vary within and among conspecific populations, and require careful evaluation and analysis. We provide guidelines for the taxonomic interpretation of advertisement call differences in sympatric and allopatric situations, and emphasize the need for an integrative use of multiple datasets (bio-acoustics, morphology, genetics), particularly for allopatric scenarios. We show that small-sized frogs often emit calls with frequency components in the ultrasound spectrum, although it is unlikely that these high frequencies are of biological relevance for the majority of them, and we illustrate that detection of upper harmonics depends also on recording distance because higher frequencies are attenuated more strongly. Bioacoustics remains a prime approach in integrative taxonomy of anurans if uncertainty due to possible intraspecific variation and technical artifacts is adequately considered and acknowledged." "A tool for labelling individual sounds from continuous recordings: An application to bio-acoustics" "Vasileios Exadaktylos, Daniel Berckmans" "Bio-acoustics is a common tool for studying health, welfare and behavior of living organisms. Current practice consists of manually extracting and labelling individual sounds out of continuous recordings. This paper presents an application tool for speeding up bio-acoustical analysis. In particular, a semi-automatic tool has been developed that enables the extraction of individual sounds from continuous recordings. Although the approach can be applied to any kind of recordings, in the present study, the focus is on extracting individual pig sounds from recordings within a pig stable. More specifically, the sound extraction is based on the amplitude of the sound signal. The energy envelope of the signal is automatically extracted using the Hilbert transform on the discrete time signals. Subsequently, the individual sounds are presented to the user for manual labelling. The front-end provides the user with tools to adjust the length of the individual sounds since it is understood that in various cases a longer or shorter part of the signal may have been identified as an individual sound. The user also has an overview of the complete recording, the number of identified sounds, and the spread of the sounds within the continuous recording. Finally, the user is allowed to label using a predefined gamut of sounds or adding a sound category that has not been foreseen, making it a flexible tool. The labeling tool also allows the integration of an automatic sound classifier in the future and can be used for both training and/or validating algorithms under development. At a later stage the tool can be connected either online or offline to a web-based database that can allow for a collection of labeled sounds to be created." "Parselmouth for bioacoustics: automated acoustic analysis in Python" "Yannick Jadoul, Bart De Boer, Andrea Ravignani" "Bioacoustics increasingly relies on large datasets and computational methods. The need to batch-process large amounts of data and the increased focus on algorithmic processing require software tools. To optimally assist in a bioacoustician’s workflow, software tools need to be as simple and effective as possible. Five years ago, the Python package Parselmouth was released to provide easy and intuitive access to all functionality in the Praat software. Whereas Praat is principally designed for phonetics and speech processing, plenty of bioacoustics studies have used its advanced acoustic algorithms. Here, we evaluate existing usage of Parselmouth and discuss in detail several studies which used the software library. We argue that Parselmouth has the potential to be used even more in bioacoustics research, and suggest future directions to be pursued with the help of Parselmouth." "BIOACOUSTICS: A TOOL FOR DIAGNOSIS OF RESPIRATORY PATHOLOGIES IN PIG FARMS" "Daniel Berckmans" "Lowland panmixia versus highland disjunction: genetic and bioacoustic differentiation in two species of East African White-eye birds" "Jan Christian Habel, Werner Ulrich, Gustav Peters, Martin Husemann, Luc Lens" "Bio-acoustic tracking and localization using heterogeneous, scalable microphone arrays" "Erik Verreycken, Ralph Simon, Brandt Quirk-Royal, Walter Daems, Jesse Barber, Jan Steckel" "Microphone arrays are an essential tool in the field of bioacoustics as they provide a non-intrusive way to study animal vocalizations and monitor their movement and behavior. Microphone arrays can be used for passive localization and tracking of sound sources while analyzing beamforming or spatial filtering of the emitted sound. Studying free roaming animals usually requires setting up equipment over large areas and attaching a tracking device to the animal which may alter their behavior. However, monitoring vocalizing animals through arrays of microphones, spatially distributed over their habitat has the advantage that unrestricted/unmanipulated animals can be observed. Important insights have been achieved through the use of microphone arrays, such as the convergent acoustic field of view in echolocating bats or context-dependent functions of avian duets. Here we show the development and application of large flexible microphone arrays that can be used to localize and track any vocalizing animal and study their bio-acoustic behavior. In a first experiment with hunting pallid bats the acoustic data acquired from a dense array with 64 microphones revealed details of the bats’ echolocation beam in previously unseen resolution. We also demonstrate the flexibility of the proposed microphone array system in a second experiment, where we used a different array architecture allowing to simultaneously localize several species of vocalizing songbirds in a radius of 75 m. Our technology makes it possible to do longer measurement campaigns over larger areas studying changing habitats and providing new insights for habitat conservation. The flexible nature of the technology also makes it possible to create dense microphone arrays that can enhance our understanding in various fields of bioacoustics and can help to tackle the analytics of complex behaviors of vocalizing animals." "Low-cost synchronization of high-speed audio and video recordings in bio-acoustic experiments" "Dennis Laurijssen, Erik Verreycken, Walter Daems, Herbert Peremans, Jan Steckel" "In this paper, we present a method for synchronizing high-speed audio and video recordings of bio-acoustic experiments. By embedding a random signal into the recorded video and audio data, robust synchronization of a diverse set of sensor streams can be performed without the need to keep detailed records. The synchronization can be performed using recording devices without dedicated synchronization inputs. We demonstrate the efficacy of the approach in two sets of experiments: behavioral experiments on different species of echolocating bats and the recordings of field crickets. We present the general operating principle of the synchronization method, discuss its synchronization strength and provide insights into how to construct such a device using off-the-shelf components." "Distributed low-cost microphone array for 3D localization for bio-acoustic applications" "Erik Verreycken, Walter Daems, Jan Steckel" "In this paper we present a multi-scale microphone array aimed at 3D source localization, with applications in bioacoustic animal tracking. We propose a hardware architecture for wirelessly synchronized sensor nodes consisting of small 5-element microphone arrays. Using this distributed sensor array we set up a probabilistic source localization problem, which we subsequently demonstrate to be able to estimate the position of a bat-like sound source in three dimensions. The proposed hardware architecture allows scalable source localization in a wide variety of application domains." "Cryptic diversity in Amazonian frogs: Integrative taxonomy of the genus Anomaloglossus (Amphibia: Anura: Aromobatidae) reveals a unique case of diversification within the Guiana Shield" "Jean-Pierre Vacher, Philippe Kok, Miguel Trefaut Rodrigues, Jucivaldo Dias Lima, Andy Lorenzini, Quentin Martinez, Manon Fallet, Elodie Courtois, Michel Blanc, Philippe Gaucher, Maël Dewynter, Rawien Jairam, Paul Ouboter, Christophe Thébaud, Antoine Fouquet" "Lack of resolution on species boundaries and distribution can hamper inferences in many fields of biology, notably biogeography and conservation biology. This is particularly true in megadiverse and undersurveyed regions such as Amazonia, where species richness remains vastly underestimated. Integrative approaches using a combination of phenotypic and molecular evidence have proved extremely successful in reducing knowledge gaps in species boundaries, especially in animal groups displaying high levels of cryptic diversity like amphibians. Here we combine molecular data (mitochondrial 16S rRNA and nuclear TYR, POMC, and RAG1) from 522 specimens of Anomaloglossus, a frog genus endemic to the Guiana Shield, including 16 of the 26 nominal species, with morphometrics, bioacoustics, tadpole development mode, and habitat use to evaluate species delineation in two lowlands species groups. Molecular data reveal the existence of 18 major mtDNA lineages among which only six correspond to described species. Combined with other lines of evidence, we confirm the existence of at least 12 Anomaloglossus species in the Guiana Shield lowlands. Anomaloglossus appears to be the only amphibian genus to have largely diversified within the eastern part of the Guiana Shield. Our results also reveal strikingly different phenotypic evolution among lineages. Within the A. degranvillei group, one subclade displays acoustic and morphological conservatism, while the second subclade displays less molecular divergence but clear phenotypic divergence. In the A. stepheni species group, a complex evolutionary diversification in tadpole development is observed, notably with two closely related lineages each displaying exotrophic and endotrophic tadpoles." "A third microendemic to the Iwokrama Mountains of central Guyana: a new ""cryptic"" species of Allobates Zimmerman and Zimmerman, 1988 (Anura: Aromobatidae)." "Philippe Kok, Monique Hoelting, Raffael Ernst" "The aromobatid frog Allobates amissibilis sp. nov. is described from a very limited area in the Iwokrama Mountains at elevations between 160 and 950 m, in central Guyana, South America. The new taxon is diagnosed from other Allobates species by morphology, bioacoustics, and genetics, and can be distinguished readily from known congeners by cryptic colouration, small size (16.3–17.8 mm snout-vent length), absence of distinct dorsal pattern in living adult individuals, presence of a distinctly enlarged tubercle on each eyelid, diffuse broad oblique lateral stripe extending from groin to about midbody length, sexually dimorphic throat colouration (pinkish grey, suffused with dark pigment in male, immaculate cream to yellow in female), belly cream to yellow in both sexes, and distinct vocalisation formed by calls of usually 9–12 notes emitted between silent intervals of usually ca. 2–6 s, with a dominant frequency ranging from 5,064 to 5,845 Hz. The new species is the third microendemic reported from the Iwokrama Mountains together with the caecilian Caecilita iwokramae and the lizard Gonatodes timidus. We recommend considering the conservation status of the new species as Data Deficient, and highlight that environmental impact assessments are needed to refine its IUCN threat status."