Acoustic variability among male gladiator frogs, Boana goiana (Lutz, 1968) (Anura: Hylidae): an 18-year analysis across several reproductive seasons

Abstract

Male anurans emit different call types in specific social contexts. Such calls represent a communication pathway for species recognition, mate choice, and male-male competition mediation. The acoustic parameters of these calls can be under directional and/or stabilizing selection due to female choice, which influences intra- and inter-individual call variation. Herein, we investigated the inter-year variation of the advertisement and aggressive calls of the gladiator frog Boana goiana, analysing a temporal series encompassing 18 years of sampling (1996-2014). We measured and analysed the following acoustic parameters: call duration, call repetition rate, number of pulses, pulse duration, pulse repetition rate, and dominant frequency. For both call types, the dominant frequency was classified as a static parameter (CVintra < 5%), while call duration was a dynamic parameter (CVintra > 12%). The advertisement call of B. goiana presents the attributes that could allow individual recognition in the chorus, and we suggest that the aggressive calls might also be important for the individual recognition process. Pulse duration of the advertisement and aggressive calls decreased over the years, as well as the repetition rate of the aggressive calls, which could be related to male body size decrease over the years probably related to habitat alteration. This study provides data on the variation of anuran acoustic features over the longest time span ever analysed. Such studies are less invasive and useful for conservation purposes, since they can detect changes in the reproductive behaviour of populations that might be under environmental modification pressure.

Neural activities in music frogs reveal call variations and phylogenetic relationships within the genus Nidirana

“…In other words, the more closely related species within the same genus exhibit more similar acoustic attributes, suggesting that some call parameters may present a powerful phylogenetic signal in this genus, similar to findings in other anuran species 23 , 69 . Studies on the concomitant divergence of advertisement calls and genetic characters in anurans have yielded contrasting results, supporting both correspondences between the diverging traits 19 – 23 , 69 and a lack of association between the two domains 28 – 30 . These contrasting results occur because two evolutionary impacts with opposing direction act on the signal system, i.e.…”

“…However, many reports have explored the correlation between the divergence of advertisement calls and geographic distance between populations and/or phylogenetic distance between anuran species, with varying results depending on the species/clades and acoustic parameters. For some clades/acoustic parameters, there is a strong phylogenetic signal 19 – 23 or correlation with geographic distance 24 – 27 , while for other clades/acoustic parameters this is not the case 28 – 35 . For example, signal structures in some anuran species appear to be highly conservative within species, while some closely related species often exhibit similar acoustic signals 19 – 22 .…”

“…For some clades/acoustic parameters, there is a strong phylogenetic signal 19 – 23 or correlation with geographic distance 24 – 27 , while for other clades/acoustic parameters this is not the case 28 – 35 . For example, signal structures in some anuran species appear to be highly conservative within species, while some closely related species often exhibit similar acoustic signals 19 – 22 . Thus, these anuran vocalizations should be related to genetic differences to a certain extent, consistent with the diversity of anurans acoustic signals 23 .…”

Visual Signals Are Not Performed More Frequently by Nocturnal Treefrogs in Naturally Noisier Environments

“…We conducted the study between November 2009 and February 2013 at the National Forest of Silvânia (16°39ʹ32″S, 48°36ʹ29″W), Municipality of Silvânia, Goiás, located within the Cerrado biome, Brazil. The National Forest of Silvânia has a tropical climate with an annual mean temperature of 26℃ and an annual mean rainfall of 1,600 mm (Bastos et al, 2003a). There are two welldefined seasons (Morais et al, 2012): a rainy season (October-March) and a dry season (April-September).…”

“…Boana albopunctata (Fig. 1B) is a common treefrog from Brazil found in lentic environments most of the year (Bastos et al, 2003a). Males perch on marginal vegetation and call in chorus (Bastos et al, 2003a), and both advertisement and territorial calls were redescribed by Toledo et al (2007) and Furtado et al (2016).…”