关键词: 棉铃虫, 拒食剂, 胡椒碱, 山椒醇, 味觉习惯化, 取食经历

Abstract: 【Objective】Feeding deterrents or anti-feedants are a broad range of chemicals regulating the feeding behaviour via altering the palatability of crops to herbivores. The idea of pest ecological control using feeding deterrents is an alternative strategy to overcome the negative effect of chemical control. However, almost all insect pests can develop experience-dependent adaptivity to various feeding deterrents, especially gustatory habituation, which limited the practical use of these substances. The objective of this study is to elucidate the sensory organs involved in the feeding deterrence of two amides against a generalist herbivore, Helicoverpa armigera (Hübner), and the effect of prior feeding experience of piperine and sanshool on subsequent feeding behaviour of the larvae, providing a scientific basis for large-scale application.【Method】The olfactory approaching response under dual-choice condition with piperine- and sanshool-treated with tobacco leaf discs was tested, respectively, paired with the control leaf disc, and the feeding duration of the larvae after first encounter with the piperine- or sanshool-treated tobacco leaf discs under non-choice condition was measured. Then the effect of larval feeding experience to piperine and sanshool on their subsequent choice feeding behaviour was tested based on the concentrations at 50% feeding deterrence against the fourth instar larvae. 【Result】Piperine and sanshool did not exhibit any repellent effect, and the feeding durations of the larvae after first encounter with piperine- and sanshool-treated tobacco leaf discs were approximately 30 s, significantly shorter than that of the control (longer than 100 s). This feeding duration time was in accordance with the typical post-ingestive response time of a model insect species, Manduca sexta. The concentrations at 50% feeding deterrence to the fourth instar larvae of piperine and sanshool were 0.2259 and 0.4003 mg per tobacco leaf disc (1.5 cm ID), respectively. The bioassay of feeding experience showed that the larvae with piperine- and sanshool-feeding experiences were significantly deterred by the corresponding experienced substances, suggesting that no significant habituation occurred when the two amides were mixed with the artificial diet at the concentrations of 50% feeding deterrence to the fourth instar larva and when larval feeding experience was induced from the third instar to the fifth instar. The larvae experienced with sanshool were also deterred significantly by piperine. However, the larvae experienced piperine developed gustatory habituation to sanshool, demonstrating an asymmetric cross-habituation between these two amides. The binary mixture of piperine and sanshool could not mitigate the gustatory habituation of the larvae, whether considering the difference between the feeding consumption of the treated and control tobacco leaf discs within each experience group, or considering the feeding deterrence rates between of different experience group when tested under the same conditions. The possible reasons were discussed with respect to the induced stage and the mechanism of the tested substances deterring feeding. The binary mixture of piperine and sanshool could not mitigate the decrease in feeding deterrent response following prolonged exposure.【Conclusion】Feeding of H. armigera larvae was deterred by piperine and sanshool via gustatory post-ingestive effect. No significant gustatory habituation occurred when the experienced stimuli paired with the control, and it seems that the binary mixture of piperine and sanshool could not mitigate the habituation. The two amides have a broad prospect in field application.

Key words: Helicoverpa armigera, feeding deterrent, piperine, sanshool, gustatory habituation, feeding experience