READ ME for fitness_data.xlsx spreadsheet "rawdata_9months" describes the measurements for "survivorship", for "fecundity", and for "sensus" after 9 months of experimental evolution. This includes the values per replicate, and the mean and standard deviation plotted in Figure 2 of the main manuscript. The sequenced lines are labelled and colored following the same codes as in the main manuscript. spreadsheet "summary_9months" this table summarises all the results from the spreadsheet "rawdata_9months", as they are plotted in Figure 2. spreadsheet "survivorship_timeseries" this contains the raw data for "survivorship" measured at every generation in the left Table, together with the summary used to plot Figure S1.