2007 Annual Report 1a.Objectives (from AD-416) To determine whether the host acceptance behavior of aphid parasitoids depends on physiological state variables. 1b.Approach (from AD-416) In laboratory experiments, measure whether aphelinid parasitoids of soybean aphid are more likely to accept low-quality species of hosts when their physiological state (egg load and nutritional status) would suggest that they are unlikely to be able to lay all of their eggs. 3.Progress Report This report documents research conducted under a reimbursable cooperative agreement between ARS and the University of Minnesota. We have identified a population of APHELINUS near GOSSYPII from China as a more appropriate species for this research than APHELINUS ATRIPLICIS, the species proposed originally. APHELINUS near GOSSYPII has a much narrower host range than APHELINUS ATRIPLICIS, and thus lends itself much more to testing the effects of stressing female parasitoids on their acceptance of suboptimal hosts. We are proceeding with recruitment of a post-doctoral research associate. This research relates to Problem Statements A - Understanding Complex Interactions under National Program Component III - Plant, Pest, and Natural Enemy Interactions and Ecology; and Problem Statement A - Traditional Biological Control under National Program Component V - Pest Control Technologies. Monitoring was achieved through frequent telephone calls and emails.