入侵害虫芒果壮铗普瘿蚊对5种芒果挥发物的电生理反应和行为选择

芒果壮铗普瘿蚊（Procontarinia robusta）是我国外来危险性入侵害虫,坚硬的瘿壳导致药剂防治困难。植食性昆虫主要通过触角接收植物挥发物选择寄主,本研究采用触角电位联用仪（EAG）和“Y”型嗅觉仪观察瘿蚊成虫对芒果叶片挥发物成分（α-蒎烯、3-莰烯、α-石竹烯、异松油烯、乙酸乙酯）的电生理反应和行为选择,结果显示：EAG反应值大小排序依次为α-蒎烯>3-莰烯>α-石竹烯>异松油烯>乙酸乙酯,α-蒎烯处理组显著高于其他挥发物。虽然雌虫对于α-蒎烯、3-莰烯、α-石竹烯3种物质的EAG反应值比雄虫的高,但是雌雄之间对同一挥发物差异不显著（P<0.05）。行为选择结果显示：对瘿蚊吸引率高低依次为：3-莰烯>乙酸乙酯>α-石竹烯>α-蒎烯>异松油烯;3-莰烯对瘿蚊的吸引率最高,达到74.20%,显著高于α-蒎烯和异松油烯,乙酸乙酯吸引率次之,达到66.07%;异松油酯的趋避性最高,达到74.25%,显著高于其他挥发物。实验中也显示浓度阈值现象,α-蒎烯在浓度0.5 mL/L和1 mL/L浓度范围内有显著的趋避效果,在高于或低于此范围内的其他浓度引诱率和趋避率差异不显著。α-石竹烯高浓度（1.0 mL/L and 2.0 mL/L）对芒果壮铗普瘿蚊有显著引诱作用,3-莰烯和α-石竹烯处理组随着浓度的升高对瘿蚊的引诱率增加。研究结果为阐释瘿蚊入侵机理提供理论依据,为开发引诱剂或趋避剂提供技术支撑。

Electroantennographic and Behavioral Responses of Invasive Insect Procontarinia robusta to Five Host Plant Volatiles

Mango midge (Procontarinia robusta) is an invasive agricultural pest with high reproductive potential and controlling larvae is much more difficult because insecticide hardly enters the plant gall tissue upon which the larvae are feeding. Plant volatiles are detected by olfactory receptor neurones in sensillae which are mostly on the insect antennae. In this study, the behavioral and electrophysiological responses of five mango leaf volatiles (α-pinene, 3-camphene, α-caryophyllene, isoterpinene and ethyl acetate) to gall midge adults were observed by the methods of electroantennogram (EAG) and Y- tube olfactometer. The five volatile substances caused significantly EAG responses on both female and male. The order of EAG response value was as follows: α-pinene> 3-camphene > α-carypohylene > terpinene > ethyl acetate. The EAG value of α-pinene treatments was significant higher (P<0.05) than that of the other treatments. Although the EAG response values of female midges to α-pinene, 3-camphene and α-caryophyllene were higher than those of males, there was no significant difference (P>0.05) between the male and female for individual substance. The order of attractive rate in the experiment of behavioral responses was as follows: 3-camphene > ethyl acetate > α-caryophyllene > α-pinene > terpinene. The highest attraction rate (74.20% ) was found in 3-camphene treatments, which was significantly higher (P<0.05) than that in α-pinene and isoterpinene treatments. The attraction rate of ethyl acetate was the second and reaching 66.07%. The highest repellent rate was found in isoterpineate treatments with 74.25%, which was significantly higher (P<0.05) than that in other volatiles. Meanwhile, the experiment showed a concentration threshold phenomenon. It meant that attractant or repellent response worked only within a specific concentration range and there was no response behavioral differences above or below the threshold concentration range. In our study, significant repellent effect was presented in the a-pinene treatment with the concentration range from 0.5 mL/L to 1.0 mL/L, but no significant difference was found in the rest concentration between repellent rate and attractive rate. Higher concentrations (1.0 mL/L and 2.0 mL/L) of α-caryophyllene displayed attractive function to midges compared with lower concentrations. The attractive rate of 3-camphene and a-carypohylene treatments to gall midges increased with the concentration rising. The experimental results would provide a theoretical basis for explaining the invasion mechanisms of gall midges. Our data is helpful to developing attractants or repellent in the aspect of monitoring technology and insect management.