西藏簇角缨象天牛对核桃树七种挥发物的EAG和行为反应

EAG and behavioral responses of Cacia cretifera thibetana to seven walnut tree volatiles

【目的】为研究西藏簇角缨象天牛Cacia cretifera thibetana雌雄成虫对寄主核桃树释放的7种挥发性化合物的电生理反应和嗅觉行为反应。【方法】选取寄主三台核桃Juglans sigillata var Santai树释放的7种挥发性成分分别对西藏簇角缨象天牛进行触角电位EAG和"Y"型嗅觉仪行为反应测定。【结果】EAG测试结果表明,7种化合物在测试浓度范围内均能引起西藏簇角缨象天牛雌雄成虫的EAG反应。当化合物的浓度为0.000 4 mol×L^-1时,天牛成虫的EAG反应最弱,当化合物浓度为0.4 mol×L^-1时,天牛的EAG反应最强,其中对壬醛的EAG反应相对值最大,分别为1.84和1.74。"Y"型嗅觉行为反应测试表明,在测试浓度范围内,α-蒎烯、β-蒎烯、1-石竹烯、壬醛、桉叶油醇和反式-2-己烯醛6种化合物对天牛雌雄成虫具有引诱作用,正己醛对天牛雌雄成虫具有趋避作用;当浓度为2 mol×L^-1时,壬醛对雌性天牛成虫、β-蒎烯对雄性天牛成虫的引诱率最高,分别为95%和87%,正己醛对天牛雌雄成虫的趋避率最高为87%和78%。【结论】核桃树释放的7种化合物均能引起西藏簇角缨象天牛雌、雄成虫的EAG反应,且α-蒎烯、β-蒎烯、1-石竹烯、壬醛、桉叶油醇和反式-2-己烯醛对天牛雌雄成虫具有引诱作用,正己醛有趋避作用。该研究结果可为西藏簇角缨象天牛林间引诱剂的研发提供一定的理论依据。

[Objectives] To investigate the electroantennogram and olfactory behavioral responses of male and females of the beetle Cacia cretifera thibetana to seven volatile compounds derived from a host plant of this pest, the walnut Juglans sigillata var ‘Santai’. [Methods] Electroantennogram(EAG) and Y-tube olfactometer assays were employed to investigate the responses of C. cretifera thibetana to seven volatile components from J. sigillata var ‘Santai’. [Results] The EAG results show that the tested concentrations of all seven compounds elicited responses from both male and female beetles. The weakest EAG responses were to volatile concentrations of 0.000 4 mol/L and the highest to concentrations of 0.4 mol/L. The strongest EAG responses by males and females, 1.84 and 1.74, respectively, were elicited by nonanal. Y-tube behavioral assays showed that, within a certain range of concentration, six compounds, including alpha-pinene, beta-pinene, 1-caryophyllene, nonaldehyde, eucalyptus oil alcohol and trans-2-hexenal, were attractive to male and female beetles. N-hexyl aldehydes, however, had a repellent effect on both sexes. At a volatile concentration of 2 mol/L, females were most attracted by nonaldehyde whereas males preferred beta-pinene;chemotaxis rates of each sex for each compound were 95% and 87%, respectively. N-hexaldehyde had a repellent effect on both sexes, eliciting chemotaxis rates of 87% and 78%, respectively. [Conclusion] All seven compounds induced an EAG response, and six, including alpha-pinene, bet-pinene, 1-caryophyllene,nonaldehyde, eucalyptus oil alcohol and trans-2-hexenal, were attractive to both sexes. Only one compound, n-hexenal, had a repellent effect. These results provide a foundation for further research on attractants for C. cretifera thibetana.