Evolution of butterfly seasonal plasticity driven by climate change varies across life stages

Photoperiod is a common cue for seasonal plasticity and phenology, but climate change can create cue-environment mismatches for organisms that rely on it. Evolution could potentially correct these mismatches, but phenology often depends on multiple plastic decisions made during different life stages and seasons that may evolve separately. For example, Pararge aegeria (Speckled wood butterfly) has photoperiod-cued seasonal life history plasticity in two different life stages: larval development time and pupal diapause. We tested for climate-change-associated evolution of this plasticity by replicating common garden experiments conducted on two Swedish populations 30 years ago. We found evidence for evolutionary change in the contemporary larval reaction norm—although these changes differed between populations—but no evidence for evolution of the pupal reaction norm. This variation in evolution across life stages demonstrates the need to consider how climate change affects the whole life cycle to understand its impacts on phenology.

Methods
Please see the main paper and readme files for full details on the methods associated with this dataset.

Data on the historic experiment was digitized for this study from the original data sheets associated with Nylin et al 1989, 1995 (see main text for full citations).

Data for the contemporary experiment was generated by the authors for this study, following the methods of the historic experiment.

Temperature data came from the Swedish Hydrological and Meteorological Institute weather stations and was restructured, but otherwise used as provided by SHMI.