Data from: Local adaptation drives thermal tolerance among parasite populations: a common garden experiment

Understanding the evolutionary responses of organisms to thermal regimes
is of prime importance to better predict their ability to cope with
ongoing climate change. Although this question has attracted interest in
free-living organisms, whether or not infectious diseases have evolved
heterogeneous responses to climate is still an open question. Here, we ran
a common garden experiment using the fish ectoparasite Tracheliastes
polycolpus, (i) to test whether parasites living in thermally
heterogeneous rivers respond differently to an experimental thermal
gradient, and (ii) to determine the evolutionary processes (natural
selection or genetic drift) underlying these responses. We demonstrated
that the reaction norms involving the survival rate of the parasite larvae
(i.e. the infective stage) across a temperature gradient significantly
varied among six parasite populations. Using a Qst/Fst approach and
phenotype-environment associations, we further showed that the evolution
of survival rate partly depended upon temperature regimes experienced in
situ, and was mostly underlined by diversifying selection, but also -to
some extent- by stabilizing selection and genetic drift. This evolutionary
response led to population divergences in thermal tolerance across the
landscape, which has implications for predicting the effects of future
climate change.