PRODUCTION OF EARLY EXPRESSED PARASITISM-SPECIFIC PROTEINS IN ALTERNATE SPHINGID HOSTS OF THE BRACONID WASP COTESIA-CONGREGATA

Parasitism of Manduca sexta larvae by the braconid wasp Cotesia congre gata or injection of C. congregata polydnavirus (CcPDV) causes numerou s alterations in host physiology, including developmental arrest, abro gation of host immunity, and the production of three abundant early ex pressed proteins (EP1, EP2, and EP3) that are secreted in large amount s into the host's hemolymph. Here me compare the levels of these prote ins present in the hemolymph of three other sphingid species that vary in their compatibility for C. congregata. Hyles lineata was found to be permissive for C. congregata and EP1, EP2, and EP3 were present in larval hemolymph at levels comparable to those found in hemolymph from parasitized M. sexta larvae. By contrast, the lowest levels of EP pro teins were found in hemolymph from parasitized Pachysphinx occidentali s larvae and this species was found to be completely refractory, since C. congregata eggs were invariably encapsulated. Parasitism of Sphinx vashti by C. congregata resulted in moderate levels of EP production. While the observed immune response was incomplete and some encapsulat ion of C. congregata eggs and/or larvae was observed, low numbers of S . vashti nevertheless were able to complete their development and emer ge as adults. Thus, a correlation was established between host compati bility and induction of synthesis of the three parasitism-specific pro teins, although the linkage between quantitative levels of EP producti on and the extent of encapsulation was variable. (C) 1998 Academic Pre ss.