Climate and Morphology Drive Breeding Periods in Frogs

Aim Climate can have profound effects on reproductive behavior and physiology, especially in ectothermic animals. Breeding periods in amphibians have received little attention despite amphibian reliance on climate and water due to their reproductive biology and ecological diversity. The aim of this study is to determine how global climate impacts breeding periods in ectothermic animals through physiology, body size, and microhabitat. Location All continents, except Antarctica. Time period Breeding periods and climate both dating as far back as 1970. Major taxa studied 497 (7%) anuran species of 41 (76%) families. Methods We used phylogenetic comparative methods to analyze a global dataset of frog breeding periods, climate, body size, and microhabitat for 497 species. Results We found support for a global latitudinal gradient of breeding periods which are longer in the warmer, wetter tropics while shorter in the colder, dryer temperate zone. Latitudinal and non-latitudinal global patterns of breeding period were composites of the same patterns in the temperate and tropical zones. However, the effect of climate and body size in each zone is unique. Breeding periods displayed weak phylogenetic signal and were similar across microhabitats. Main conclusions Breeding periods show a global latitudinal gradient but this concept breaks down within the tropical zone. Our results are consistent with the importance of physiology in driving breeding periods and we describe how breeding period and body size may exhibit trade-offs which make latitudinal gradients context-dependent. Our results set within an ecophysiological framework have broad implications for understanding reproductive diversity in other ectothermic organisms.