Passive evasion by eggs of braconid parasitoid Cardiochiles nigriceps of encapsulation in vitro by haemocytes of host Heliothis virescens. Possible role for fibrous layer in immunity

摘要: Abstract We have utilised a novel in vitro encapsulation system using haemolymph of the host, Heliothis virescens and eggs parasitoid, Cardiochiles nigriceps (as targets for encapsulation) to examine properties egg surface with respect recognition by host haemocytes. Many biotic abiotic were readily encapsulated vitro, exception negatively charged cation exchange beads allogenic tissue. However, mature eggs, which had 0.5 – 1.0 μm thick fibrous layer on their outer surface, not regardless whether they developing, dormant or been killed ultra-violet irradiation. Conversely, immature sheath follicle cells over layer, encapsulated; similarly, experimental removal driselase H. zea also caused elicit an response. Identical responses occur if are injected manually into larvae. The data suggest that C. can evade haemocytes independently other “immunosuppressants” such as calyx fluid/virus, venom teratocytes. It is proposed may, among possible functions, delay until more permanent means suppressing established host.