Project leader: Max Ringler
Collaborators: Robert Höldrich (IEM/KUG), Palmyre Boucherie (Univ. Vienna), Eva Ringler (Univ. Bern)
Funded by the Austrian Science Fund (FWF): https://www.fwf.ac.at/
In the evolution of social behaviour in vertebrates, amphibians take a paradoxical position, as to date no form of so-called ‘higher’ social organisation (e.g. living in social groups, persistent social structures, helper systems, coordinated foraging) is known in any amphibian. This is remarkable, because ‘higher sociality’ occurs in all other major vertebrate taxa. It is featured by several fish species and even more by many tetrapods – mainly birds and mammals, but to a lesser extent also by some reptiles. We hypothesize, that also in amphibians some degree of social organisation is present; that it should evolve sooner or later; or probably is currently in statu nascendi – as it is suggested by the prevalence of several ‘building blocks’ of social and communicative complexity in this group. Such adaptations include individual and kin recognition, structured communication, advanced orientation, temporal and/or spatial memory, prolonged territorial behaviour, high mate selectivity, elaborate mate choice mechanisms, and parental care.
In this project, we want to investigate the level of complexity of amphibian social organisation and thereby also establish a new, amphibian, model species for social behaviour research. We believe that investigating the structures and dynamics of frogs’ communication networks will provide valuable insights to better understand if, and how, frogs are socially organised. We start this investigation in the, in our opinion, most promising taxon – Neotropical poison frogs (Dendrobatidae) – with the intensively studied Brilliant-thighed Poison Frog Allobates femoralis. We employ state-of-the-art acoustic recording technology with sound source localization and individual recognition, combined with field observations, to record and quantify the full acoustic communication of an entire population of free ranging poison frogs. Using social network analysis, we will describe the communication network and evaluate its robustness through time and demographic changes. In a second step, using genetic sampling and pedigree estimation, we will measure the individual reproductive success and correlate it with individual calling activity and position in the CN to determine the role of calling in mate choice, and to identify related fitness effects and selective pressures.
Monitoring the calling activity of an entire poison frog population is only possible with passive acoustic recorders, utilizing sound source localisation, and individual recognition of individuals. To this is end, we are currently developing “SonicSpotter”, a large-scale wireless microphone array based on commercially available hardware (Raspberry Pi & ReSpeaker), in combination with a user-friendly software with a graphical user interface to conduct sound source localization and identify individual calling frogs. The development of the SonicSpotter is a collaboration with the Institute of Electronic Music and Acoustics at the University of Music and Performing Arts, Graz, Austria, and the two companies “sonible” (hardware development; www.sonible.com) and “atmoky” (software development; www.atmoky.com) which are specialised in the reproduction and signal analysis of spatial audio. The system has currently undergone the first field-testing season and a second generation of SonicSpotter nodes has been developed based on field experiences. We are looking forward to deploy the first productive Spotters in our next field season in April-May 2023.
Prof. Robert Höldrich, IEM/KUG