This data was generated to test how hybridization of an introduced insect biological control agent impacts host use. The data characterize the species composition of individual *Diorhabda spp.* collected across New Mexico and Texas, USA. Species composition of each individual was determined using genomic methods and Structure. Lab reared colonies were tested for host specificity, by measuring feeding preference in 24-hour feeding tests and measuring frass deposited below three host plants. Data on several attributes were also collected, including body mass, fecundity during the 24-hour feeding trial, and oviposition preference. The larval offspring of these individuals were also reared in families for 12 days on the three host plants and larval survival and mass were measured to quantify larval performance on the hosts.