Effect of venom from Diadromus collaris on immunity activity of its natural host and non-target lepidopteran insects

摘要

Venom of parasitoids can regulate host physiology to favor development of the parasitoid. Effects of venom from Diadromus collaris ( Hymenoptera: Ichneumonidae) on the immune system, including hemocytes and phenoloxidase activity, of its natural hostPlutella xylostella ( Lepidoptera: Plutellidae) and non-target lepidopteran insects Pieris rapae (Lepidoptera: Pieridae) and Ostrinia furnacalis ( Lepidoptera: Pyralidae) were studied. The results showed that venom from D. collaris strongly affects hemocytes of its natural host, P. xylostella, less on the non-target host, P. rapae, which feeds on the same plant, Chinese cabbage, and not on the non-target host, 0. furnacalis, that feeds on corn. Spreading and viability of granular from P. xylostella wereboth 50% ±3% after incubation with venom for 3 hours, and that of plasmatocytes were 5% and 20% ± 1%, respectively. Influence on P. rapae was slight, spreading and viability of granular cells were 98% ± 1% and 73% ±4% and that of plasmatocytes were98% ±1% and 65% ±2% respectively, when hemocytes were incubated with venom for 3 hours. Moreover, there was no effect on hemocytes of 0. furnacalis in spreading or viability. The same trend of venom on activity of phenoloxidase was shown. In conclusion, venom effect on immunity of the natural host P. xylostella was prefered and the plasmatocyte are predominant.