Foraging success is differently affected by local climate in two syntopic forest-dwelling salamanders

Abstract

Amphibians are small ectothermic vertebrates with high permeable skins that are highly constrained by environmental conditions, such as humidity and temperature. Therefore, terrestrial salamanders regulate their surface activity, including foraging, to minimize evaporative water loss. The influence of local micro-climatic factors on the foraging success of European forest dwelling salamanders has rarely been analysed in detail. We examined the role of local climatic conditions on the foraging success, measured by the total number of prey items, of two syntopic forest-dwelling salamanders: Strinati’s cave salamander, Speleomantes strinatii (family Plethodontidae), and Northern spectacled salamander, Salamandrina perspicillata (family Salamandridae). We evaluated the effects of rainfall, temperature and body size on the foraging success of these two species, in eight sampling sites in the Northern Apennines of Italy, for a total of 11 salamander populations. Our findings show that different climatic variables affected the two species differently. Salamandrina perspicillata foraged more intensively during periods of prolonged rainfall with higher temperatures. On the contrary, S. strinatii foraging success was negatively influenced by rising temperature, while rainfall seemed to have no significant effect. Interestingly, body size increased success in S. perspicillata but not in S. strinatii. Overall, our findings show that, when foraging in the same environment, these two species are conditioned by different climatic factors possibly due to their differences in overall body size and their ability to resist dehydration.