华北大黑鳃金龟幼虫对3种寄主植物根系分泌物的趋性反应

华北大黑鳃金龟幼虫是我国北方地区为害植物根系的重要土壤害虫,探索寄主根系分泌物对其引诱作用,可以为开发大黑鳃金龟幼虫引诱剂等绿色防控提供理论基础.以纯净空气作为对照,利用“Y”型嗅觉仪分别测定了3龄幼虫对花生、大豆、玉米根系的趋性反应.以正己烷为对照,采用GC-MS分析鉴定3种根系分泌物的成分,观测试虫对其主要成分的嗅觉反应.结果表明: 华北大黑鳃金龟幼虫对花生、大豆和玉米根系都具有显著的趋向性.通过GC-MS分析鉴定发现,根系分泌物主要成分在3种植物中均有20种及以上,而且在不同植物之间除丙三醇、十二醇和乙苯3种共有组分之外,其余组分存在明显差异.分泌物的趋性反应结果显示,供试幼虫对分泌物同一组分不同浓度的趋性反应程度明显不同.在浓度为40和80 μg·mL^-1时,2-丁烯酸、甲基丁二酸、肉豆蔻酸、乙酸和邻苯二甲酸等的引诱虫数显著多于对照;在浓度为100、200 μg·mL^-1时,化合物十四烷和十六烷等的引诱虫数显著多于对照.在浓度为300、500 μg·mL^-1时,供试幼虫对对二甲苯、邻二甲苯和棕榈酸甘油酯等有显著的趋向性反应.可见,植物根系分泌物的主要成分对华北大黑鳃金龟幼虫具有显著的引诱作用.

Behavioral responses of Holotrichia oblita larvae to root exudates from three host plants

The larva of Holotrichia oblita is a serious soil pest that feed with plant roots in north China. To explore the effects of host root exudates on the larva could provide theoretical basis for the development of green prevention and control methods. In order to elucidate the behavioral responses of Holotrichia oblita larva to the roots of peanut, soybean and maize, an experiment was conducted using the Y-olfactometers with the air as control. The constituents of the root exudates from the three host plants were identified by the gas chromatography-mass spectrometer (GC-MS). The olfactory responses of H. oblita larvae to the main components were tested. The results showed that H. oblita larvae had a significant behavioral preference toward the roots of peanut, soybean and maize than the control. The GC-MS analysis showed that the main components of volatile compounds in the three plants had more than twenty compounds, with only three shared ones, which was glycerol, dodecanol, ethyl benzene. The results of the Y-olfactometers showed that at low concentrations (40 to 80 μg·mL^-1), the number of insects attracted by compound 2-butenoic acid, methylsuccinic acid, myristic acid, acetic acid and phthalate was significantly higher than that of control. At the concentrations of 100 μg·mL^-1, 200 μg·mL^-1, compound tetradecane and hexadecane were more attractive to the larvae than the control. The compounds p-xylene, o-xylene, and palmitic acid glycerol were found to significantly induce the larva at the concentration of 300 μg·mL^-1 and 500 μg·mL^-1. In summary, the main components of plant root exudates had a significant luring effect on H. oblita larvae.