Supplementary information from "The role of environmental factors on visual communication in Neotropical anurans"

<b>Aim:</b> Visual signals are a widespread behavioural attribute of communication among vertebrates, often employed during intrasexual competition or mate attraction, ultimately influencing reproductive success. However, the environmental factors driving visual signal evolution remain poorly understood. We investigated how humidity and vegetation heterogeneity predict the richness of species employing visual signals and signal richness in neotropical frogs.<b>Location:</b> Neotropical Region<b>Time Period:</b> Present day<b>Major taxa studied:</b> Anurans<b>Methods:</b> Using a dataset of 236 anuran species with documented visual signals, we conducted spatial and phylogenetic analyses using Aridity Index (AI) and Normalized Difference Vegetation Index (NDVI) as proxies of humidity and environmental heterogeneity, respectively. We analysed the data for all species collectively and subsets categorised by habit (diurnal, nocturnal) and breeding habitat (lotic, non-lotic).<b>Results:</b> Our results highlight that Neotropical forests harbour the greatest species visual-signal species richness, as well as the highest gesture richness. Although we observed significant correlations between visual signal distribution and environmental predictors, their explanatory power was weak and inconsistent in both assemblage- and species-level approaches.<b>Main Conclusions:</b> We propose that visual signals in anurans are predominantly used in water-saturated environments over short distances, which may explain the poor correlations with broad-scaled environmental predictors. Future studies should incorporate finer spatial scales and interpopulational variations to better determine the visual signals evolution in anurans.