Data package includes 3 files: 1. One text file, named "Population_fitness.txt" 2. One text file, named "Male_fitness.txt" 3. One text file, named "Hermaphrodite_fitness.txt" All authors obtained the data and Henrique Teotónio can be contacted with questions. Description: Each file is a table with measures of fitness as described in the publication. 1. File "Population_fitness.txt" is a table with 108 population fitness measures, given in the collumn named "w". The first 2 columns indicate: 1) the name of the assayed population; 2) the generation of experimental evolution from which the fitness measures were taken. 2. File "Male_fitness.txt" is a table with 84 fitness measures obtained from male competition assays, given in the collumn named "w". The first 2 columns indicate: 1) the name of the assayed population; 2) the generation of experimental evolution from which the fitness measures were taken. 3. File "Hermaphrodite_fitness.txt" is a table with 576 fitness measures obtained from hermaphrodite competition assays, given in the collumns named "w_o" and "w_s". The columns indicate: 1) the name of the assayed population; 2) the generation of experimental evolution from which the fitness measures were taken. 3) hermaphrodite fitness when outcrossed; 4) hermaphrodite fitness when selfed.