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Amphibians and reptiles are ectothermic animals and therefore depend on environmental temperatures to maintain their physiological functions. Despite being poorly documented, data on thermal behavioral thresholds to avoid overheating in their habitats are essential to improve the understanding of their thermal ecology and physiology. Here we provide a data set of 312 individual voluntary thermal maximum (VTMax) values, the maximum temperature tolerated by individuals before actively moving to a colder place, for 53 species of amphibians and reptiles of the Atlantic Forest and Cerrado savannas of southeastern South America. Voluntary thermal maximum values were recorded as the body temperature at which the individuals exited a heating box experimental setup. This data set comprises 25 species of 15 genera and eight families of amphibians and 28 species of 24 genera and 12 families of reptiles. Of the total number of individual records, 67.9% derived from the Cerrado and 32.0% derived from the Atlantic Forest ecoregions. Overall, lizards had higher VTMax than amphibians and snakes, and individuals in the Atlantic Forest had overall higher VTMax values than the ones in Cerrado. This data set is the first to compile VTMax values for South American herpetofauna, along with detailed experimental information such as heating rates and time to reach VTMax. This data set provides a baseline for understanding thermal tolerances and requirements of Neotropical ectothermic vertebrate species, which might be useful for future research on the impact of climate change and to test novel ecological hypotheses. There are no copyright or proprietary restrictions except that this data paper should be cited when data are used for publications. In addition, the authors would appreciated being informed of research projects or teaching purposes when these data are used. [ABSTRACT FROM AUTHOR]

Extrinsic environmental factors influence the distribution and population dynamics of many organisms, including insects that are of concern for human health and agriculture. This is particularly true for vector-borne infectious diseases like malaria, which is a major source of morbidity and mortality in humans. Understanding the mechanistic links between environment and population processes for these diseases is key to predicting the consequences of climate change on transmission and for developing effective interventions. An important measure of the intensity of disease transmission is the reproductive number R0. However, understanding the mechanisms linking R0 and temperature, an environmental factor driving disease risk, can be challenging because the data available for parameterization are often poor. To address this, we show how a Bayesian approach can help identify critical uncertainties in components of R0 and how this uncertainty is propagated into the estimate of R0. Most notably, we find that different parameters dominate the uncertainty at different temperature regimes: bite rate from 15°C to 25°C; fecundity across all temperatures, but especially ~25-32°C; mortality from 20°C to 30°C; parasite development rate at ~15-16°C and again at ~33-35°C. Focusing empirical studies on these parameters and corresponding temperature ranges would be the most efficient way to improve estimates of R0. While we focus on malaria, our methods apply to improving process-based models more generally, including epidemiological, physiological niche, and species distribution models. [ABSTRACT FROM AUTHOR]

Environmental temperature variation can influence physiology, biogeography, and life history, with large consequences for ecology, evolution, and the impacts of climate change. Based on the seasonality hypothesis, greater annual temperature variation at high latitudes should result in greater thermal tolerance and, consequently, larger elevational ranges in temperate compared to tropical species. Despite the mechanistic nature of this hypothesis, most research has used latitude as a proxy for seasonality, failing to directly examine the impact of temperature variation on physiology and range size. We used phylogenetically matched beetles from locations spanning 60° of latitude to explore links between seasonality, physiology and elevational range. Thermal tolerance increased with seasonality across all beetle groups, but realized seasonality (temperature variation restricted to the months species are active) was a better predictor of thermal tolerance than was annual seasonality. Additionally, beetles with greater thermal tolerance had larger elevational ranges. Our results support a mechanistic framework linking variation in realized temperature to physiology and distributions [ABSTRACT FROM AUTHOR]

Ecologists and epidemiologists worry that global warming will increase disease prevalence. These fears arise because several direct and indirect mechanisms link warming to disease, and because parasite outbreaks are increasing in many taxa. However, this outcome is not a foregone conclusion, as physiological and community-interaction-based mechanisms may inhibit epidemics at warmer temperatures. Here, we explore this thermal-community-ecology-based mechanism, centering on fish predators that selectively prey upon Daphnia infected with a fungal parasite. We used an interplay between a simple model built around this system's biology and laboratory experiments designed to parameterize the model. Through this data-model interaction, we found that a given density of predators can inhibit epidemics as temperatures rise when thermal physiology of the predator scales more steeply than that of the host. This case is met in our fish Daphnia-fungus system. Furthermore, the combination of steeply scaling parasite physiology and predation-induced mortality can inhibit epidemics at lower temperatures. This effect may terminate fungal epidemics of Daphnia as lakes cool in autumn. Thus, predation and physiology could constrain epidemics to intermediate temperatures (a pattern that we see in our system). More generally, these results accentuate the possibility that warmer temperatures might actually enhance predator control of parasites. [ABSTRACT FROM AUTHOR]