Multimodal signaling in Boana albopunctata (Anura: Hylidae): reading visual and acoustic cues

Abstract

Multimodal signaling in Boana albopunctata (Anura: Hylidae): reading visual and acoustic cues. The acoustic mode of communication is important for anurans, but visual communication is beginning to be considered essential for some species, genera, and families. This study focuses on visual and acoustic signals in Boana albopunctata (Hylidae: Cophomantinae) in an attempt to increase our understanding of signaling in this nocturnal Neotropical treefrog. Visual signals were assessed to determine whether they are directed toward conspecific opponents, as has already been observed for some diurnal anurans, or associated with potential morphological asymmetries. Associations between visual and acoustic signals were explored. The results suggest that males may combine visual and acoustic signals (multimodal signaling) synergistically, thereby strengthening the efficiency of information transmission. Thus, in nocturnal anuran species, visual signals may function primarily as an alerting component and multimodal signaling may be a relevant way of communication.

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

“…At least 21 nocturnal hylid species are known to perform visual signals during reproductive and/or aggressive contexts (see a review in Furtado et al, 2017). Therefore, our results corroborate previous studies, showing that visual repertoires in nocturnal anuran species can be diverse during social interactions (Hartmann et al, 2005; Starnberger et al, 2011; Furtado and Nomura, 2014; Furtado et al, 2017; Lourenço et al, 2020). However, our findings also suggest that nocturnal anuran species are likely fully adapted to natural variations in the background noises where they breed, overall, not increasing the performance of visual signals when in noisier natural conditions.…”

“…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). Toledo et al (2007), de Sá et al (2014), Furtado et al (2017), and Lourenço et al (2020) previously reported visual signaling by this species. Additionally, we observed males of B. albopunctata performing toe/finger trembling and limb lifting displays in the presence of a conspecific intruder male.…”

“…Thus, multimodal communication using multiple simultaneous signals can send redundant information, which increases accuracy (redundant multimodal signals hypotheses; Partan and Marler, 2005), or different information for the same or different receivers (Johnstone, 1996; Hebets and Papaj, 2005). For anurans, empirical evidence supports the idea that visual displays have redundant communication functions with acoustic signals (e.g., Furtado et al, 2017; Lourenço et al, 2020). For example, limb lifting and upright posture behaviors possibly have a similar functions to that of aggressive calls during agonistic interactions (territorial defense in Hylodes asper [Müller, 1924], Hödl and Amézquita, 2001; Micrixalus saxicola [Jerdon, 1853], Preininger et al, 2013; and Bokermannohyla sapiranga Brandão et al, 2012, Souza, 2014).…”

“…We report for the first time visual displays performed by males of Bokermannohyla sapiranga and Boana goiana, with face wiping being the only visual display previously reported for Bokermannohyla ( Bokermannohyla nanuzae [Bokermann and Sazima, 1973], Lima et al, 2014). We also added one visual display (upright posture) to the previous known visual repertoire of Boana albopunctata (limb lifting and toe/finger trembling were first reported by Toledo et al, 2007, and face wiping and vocal sac display by Lourenço et al, 2020).…”

“…Visual signals in nocturnal frog species are often recognized by the similarity with the known visual signals performed by diurnal frog species, being faster and less ritualized than those emitted by diurnal species (see Hödl and Amézquita, 2001; Lourenço et al, 2020). Exploring multimodal communication, Grafe and Wanger (2007), Preininger et al (2009), and Grafe et al (2012) conducted experiments with Staurois species and showed that calls might have alerting functions for visual signals in diurnal frog species.…”