Abstracts (first author)
Fluctuating temperature leads to evolution of thermal generalism and pre-adaptation to novel environmentsPDF
Climate change scenarios do not only expect elevated temperatures but also increased temperature fluctuations. Environmental fluctuations are suggested to select for low levels of plasticity in fitness that is also hypothesized to increase organisms’ ability to invade novel environments and affect virulence of pathogens. We tested these hypotheses and show that across a range of temperatures, opportunistic bacterial pathogen Serratia marcescens that evolved in fluctuating temperature (daily variation between 24 and 38 °C, mean 31 °C), outperforms strains that evolved in constant temperature (31° C) across all measured temperatures. Their better growth was also evident in novel environments with parasitic viruses and predatory protozoans. However, the strains from fluctuating environment were less virulent to Drosophila melanogaster host. Therefore, whilst supporting the hypothesis that evolution in fluctuating environments is paired with tolerance to several novel environments, our results show that adapting to fluctuating environments can also be costly in terms of reduced virulence. Together these results suggest that thermal fluctuations driven by the climate change could affect not only species thermal tolerance but also species’ invasiveness and virulence.