Environmental drivers of body size variation in the lesser treefrog (Dendropsophus minutus) across the Amazon-Cerrado gradient

Body size variation and sexual size dimorphism across climatic gradients in the widespread treefrog Scinax fuscovarius (Anura, Hylidae)

“…The same pattern, its inverse, and its absence have been described at the intraspecific and interspecific level (Nevo 1972;Sch€ auble 2004;Olalla-T arraga et al 2009;Yu et al 2010;Bidau et al 2011;Oromi et al 2012;Boaratti & Da Silva 2015;Oyamaguchi et al 2016).…”

“…Several studies have shown that moisture can be more correlated with intraspecific variation in body size of animals than temperature, and anurans usually follow this trend (McDiarmid 1968;Nevo 1972Nevo , 1973Yom-Tov & Geffen 2006;Castellano & Giacoma 1998;Olalla-T arraga et al 2009;Gouveia & Correia 2016;Oromi et al 2012;Oyamaguchi et al 2016; this study). Among anurans, it is expected that because they need to keep their skin moist in order to breath a simple mechanism to achieve this is decreasing the surface-to-volume ratio by increasing body size, a mechanism analogous to the conservation of heat.…”

Seasonality drives body size variation in a widely distributed Neotropical treefrog

“…An interspecific study in the Cerrado ecoregion also found a positive relationship between anurans’ body sizes and water deficit, with larger species inhabiting areas with higher water deficit (Olalla–Tárraga et al , 2009). At the intraspecific level, the same pattern was found in Dendropsopohus minutus (Oyamaguchi et al , 2016) and Scinax fuscovarius (Goldberg et al , 2017), whereas the inverse relationship was found in Boana faber and no relationship was found in Physalaemus cuvieri (Boaratti & da Silva, 2015). According to Gouveia et al (2019), increasing body size to avoid desiccation is a more effective strategy in small size anuran species, because a little increase of size in small species results in a much larger water economy in comparison to large size ones, for which investing in mechanisms to increase skin resistance may be a better strategy.…”

“…This hypothesis is based on the association among the activity of amphibians and high levels of water availability (Ficetola et al , 2010) and contradicts the water conservation hypothesis. A large body in amphibians is advantageous in both, dry climates and also in wet areas (Trochet et al , 2019); however, in this specific case, the analyses support a clearly stronger influence of seasonality over body sizes (Table 1) being in concordance with other Neotropical species (Oyamaguchi et al , 2016; Goldberg et al , 2017).…”

“…In the Neotropical region, the body size variation in amphibians seems to be related to other mechanisms beyond the heat balance (Olalla–Tárraga et al , 2009). Once water availability in the environment is crucial in amphibian’s life (Duellman & Trueb, 1994), environmental variables related to water are highly suspect to drive body size patterns in this group, being observed both intra and interspecifically (Olalla–Tárraga et al , 2009; Oyamaguchi, Oliveira & Smith, 2016). The main invoked hypothesis related to water is the ‘water conservation hypothesis’, which predicts an increase in body size towards drier regions assuming that lower surface‐to‐volume ratio of larger bodies minimizes water loss by evaporation (Ashton, 2002).…”