Technical Abstract: We combined two protein marking enzyme-linked immunosorbent assays (ELISA) with a predator gut content ELISA to monitor the quality of commercially-purchased Hippodamia convergens Guèrin-Mèneville under realistic field conditions during two field seasons in central Arizona. The protein marking ELISAs were used to differentiate released H. convergens from the native beetles. Commercially-purchased beetles marked with rabbit immunoglobulin G (IgG) were released into cotton fields and chicken IgG marked beetles were released into adjacent cantaloupe fields. Results showed that the overall native beetle population in each crop was about the same size. The recovery rates after 15 days for the released beetles were less than 1.0% over all the releases, indicating that they dispersed readily from the release site. Of the recaptured beetles containing rabbit IgG (cotton), 82.2% were recovered in cotton and 11.8% moved to cantaloupe. Of those containing chicken IgG (cantaloupe), 66.5% were recovered in cantaloupe and 33.5% moved to cotton. A predator gut content ELISA was used to determine if there were differences in the frequency of predation of released versus indigenous H. convergens on the silverleaf whitefly, Bemisia argentifolii Bellows & Perring. The proportion of beetles containing whitefly antigens was always higher for the released beetles than their native counterparts. Our results demonstrate an approach to combine protein marking and predator gut content ELISAs that allows the simultaneous comparison of feeding and intercrop movement of native and commercially-obtained biological control agents.