Data files used for the study "Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines", by Sandra Stålhandske, Philipp Lehmann, Peter Pruisscher and Olof Leimar. The package contains one data file in tab delimited text format and the R code for the analyses. File: "a_card.txt" The file contains parameters of individual pupae concerning post-diapause development. This data file contains both individuals that hatched as adults and those that did not. Column headings: num_id: Numerical ID ind_id: ID code sex: Sex of individual cold_days: Cold duration treatment locality: Locality of origin: A: Ångermanland, Northern Sweden B: Bournemouth, Southern UK D: Durham, Northern UK S: Skåne, Southern Sweden country: Country of origin hatch_YN: Whether the individual hatched as adult or not weight: Initial weight tp: Overall post-winter development time t0: Day of warm treatment on which post-diapause development starts according to the weight-loss definition td: Post-diapause development time rd: Post-diapause development rate File: "ana_hatch.R" R code for a chi square test of hatching in a text file. File: "ana_rd.R" R code for Anova and planned comparison analysis of post-diapause development data in a text file. File: "ana_tp.R" R code for Anova of post-winter development time data in a text file. File: "ana_prop_dia.R" R code for a logistic regression of likelihood of the individual immediately initiating development once in warm conditions. File: "ana_t0.R" R code for Anova of time before development is initiated once the individual has been introduced to warm conditions.