Abstract
Microplitis demolitor is a polydnavirus-carrying parasitoid that attacks the larval stage of Pseudoplusia includens and other noctuids. Parasitism or injection of wasp components like polydnavirus and teratocytes has a juvenilizing effect on P. includens development. Here we measured hemolymph juvenile hormone (JH) titers and juvenile hormone esterase activity in P. includens larvae after parasitism or injection of wasp components. Results were compared to nonparasitized larvae. During the fifth stadium, JH titers of nonparasitized larvae fluctuated between 0.08 and 0.50 ng/ml, whereas titers in parasitized larvae never fell below 2 ng/ml. P. includens larvae injected with calyx fluid plus venom or calyx fluid plus venom and teratocytes exhibited JH titers intermediate between parasitized and nonparasitized larvae. Nonparasitized larvae exhibited two peaks of JH esterase activity. The first occurred between 12 and 48 h in association with cessation of larval feeding, while the second occurred immediately before pupation. In contrast, levels of JH metabolism remained at low levels in parasitized larvae and larvae injected with calyx fluid plus venom or calyx fluid, venom and teratocytes. Only trace amounts of JH were detected in in vitro assays of teratocytes or M. demolitor larvae suggesting neither released JH into the hemolymph of parasitized larvae. Although calyx fluid plus venom and teratocytes did not elevate JH titers to the levels measured in parasitized larvae, their effects on formation of larval-pupal intermediates by P. includens were similar to those generated by exogenous application of methoprene or JH.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.