Coexisting good neighbours: acoustic and calling microhabitat niche partitioning in two elusive syntopic species of balloon frogs, Uperodon systoma and U. globulosus (Anura: Microhylidae) and potential of individual vocal signatures

Abstract

Background Most amphibians use a repertoire of acoustic signals to propagate signals in social contexts. The description of these repertoires provides a key towards the understanding of the behaviour of individuals and the evolutionary functions of calls. Here, we assessed the variations in advertisement calls within and between two fossorial sympatric species, Uperodon systoma and Uperodon globulosus, that share their breeding season and breeding sites. For each species, we applied Beecher’s index of total information capacity (HS) for the individual vocal signature, determined the difference in call properties and demonstrated the segregation in the calling microhabitat niche between the two species. Results Our results demonstrated that the advertisement calls of U. systoma are pulsatile with a call rate of 3.00 ± 0.97 calls per second while those of U. globulosus are not pulsatile with a lower call rate of 0.53 ± 0.22 calls per second. For both species, the variations in call properties among individuals was higher than that within individual, a pattern consistent with that of other fossorial anurans. The body condition and air temperature did not significantly impact the call properties of either species. The outcome of the Beecher’s index (HS) showed that the calls of U. systoma can be used to identify 14 different individuals and the calls of U. globulosus can be used to identify 26 different individuals. The statistical analyses on the advertisement call of the two species showed a significant difference in the temporal properties as the call duration, and fall time and rise time were significantly different between the two species. Lastly, we successfully demonstrated that there is a clear segregation in calling site microhabitat between the two species, where U. globulosus calls floating close to the bank of the waterbody while U. systoma calls floating further away from the bank. Conclusion This study highlights the potential for pre-mating isolation, character displacement and assortative mating in two syntopic fossorial anurans, leading to association between acoustic, calling microhabitat niche and body index divergence as important behavioural and ecological traits.

An Isolated and Deeply Divergent Hynobius Species from Fujian, China

“…The call was recorded at a sampling rate of 44.1 kHz with a 16-bit resolution. We analyzed the call properties following the method in Prasad et al [48] using Raven Pro bioacoustics v.1.5 (Center for conservation bioacoustics; Ithaca, NY, USA).…”

Patterns of acoustic phenology in an anuran assemblage of the Yungas Andean forests of Argentina

“…Although there is a behavioural continuum between these two extremes (Wells, 1977;. Several works focused on better describing the breeding acoustic strategies that can be found in anuran species (Chen et al, 2023;Donnelly and Guyer, 1994;Forti et al, 2022;Huang et al, 2001;Prado et al, 2005;Prasad et al, 2022;Bertoluci and Rodrigues, 2002) but there is still missing information mainly for Neotropical anurans. Continuous monitoring of anuran advertisement calls along different spatial-temporal scales, can provide valuable information about the different breeding strategies displayed by each species within an assemblage (Moreira et al, 2007).…”