Here we provide the data that have been used in the paper ‘Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae).’ We provide three different sets of data: - Raw data: Excel files containing the raw data collected during field observations. This folder contains four files: A.eximius - Marking and Colony Composition A.eximius – Web Maintenance S.sarasinorum – Marking and body sizes S. sarasinorum – Web maintenance Information about column headings are provided as comments directly in the excel file. - R scripts: Scripts that have been used to perform the statistical analysis in R. This folder contains three files: - Extended hypergeometric distribution model - Life Stage composition in A. eximius - Prosoma width in S. sarasinorum Information about the scripts are provided directly into the TinnR files. The Extended hypergeometric distribution model script analyzes attacking behavior in S. sarasinorum. This script is the same that has been used for analyzing attacking and web maintenance behaviors in both S. sarasinorum and A. eximius. - Data files for R: Data files that have been used for the statistical analyses in R. This folder contains four files: - Life stages in A. eximius - Body sizes in S. sarasinorum - Extended hypergeometric Distribution Model - S_sarasinorum_D1_2 - Extended hypergeometric Distribution Model - S_sarasinorum_D2_3 The latter two file contain data regarding attacking behavior in S. sarasinorum extracted from the raw data file (“S.sarasinorum – Marking and body sizes” in the “Raw data” folder) and rearranged in order to be analyzed in R. Data regarding attacking behavior in A. eximius and web maintenance behaviour in both S. sarasinorum and A. eximius had the same structure and have been analyzed using the “Extended hypergeometric distribution model R script”.