麦长管蚜对E-β-法尼烯的嗅觉行为反应

Behavioral responses of Sitobion avenae(Hemiptera: Aphididae) to E-β-farnesene

【目的】测定麦长管蚜Sitobion avenae Fabricius对E-β-法尼烯(E-β-farnesene,EβF)矿物油溶液反应的最低阈值浓度,为EβF的田间应用提供依据。【方法】观察麦长管蚜3龄若蚜对不同浓度EβF的逃逸行为和"Y"型管嗅觉行为反应。每天定时分5次(9:00,11:30,14:00,16:30和19:00)滴加10μL EβF于滤纸上,滤纸用牙签固定于麦苗盆中心,持续处理5 d。每盆麦苗处理前接1龄若蚜15头。记录成蚜翅型及2周后蚜虫总数量。【结果】随着EβF浓度升高,麦长管蚜3龄若蚜3 min内逃离数显著增加,有翅蚜比例显著增加,种群个体数量显著下降,驱避效果明显增强。EβF浓度为200 ng/μL和≥600 ng/μL使蚜虫逃离数显著增加(P<0.05)。"Y"型管选择行为测试结果表明,EβF≥600 ng/μL对3龄若蚜具有极显著的驱避作用(P<0.01)。与对照相比,EβF≥600 ng/μL处理极显著提高了有翅蚜比例(P<0.01);EβF≥400 ng/μL极显著抑制蚜虫种群个体数量增长(P<0.01),但与600 ng/μL处理差异不显著。【结论】600 ng/μL EβF矿物油溶液为麦长管蚜驱避剂的最低阈值浓度。

[ Aim] The objective of this research was to determine the low threshold concentration of E-β- farnesene （EβF） in paraffin oil for repelling the wheat aphid, Sitobion avenae, and to provide a reference for field application of EβF. [ Methods] The effects of different doses of EβF on escaping behavior of the 3rd instar nymphs of S. avenae on wheat seedlings and their behavioral response in Y-tube olfactometer were investigated. Wheat seedlings in a pot were infested with 15 individuals of the 1st instar nymphal aphids. Filter paper strips impregnated with 10 μL of EβF at different concentrations were attached to toothpicks which were placed at the central area of the pot. Filter paper strips were replaced five times every day （9：00, l 1：30, 14：00, 16：30 and 19：00） for consecutive five days, and winged and wingless adult aphids were recorded. After two weeks, the population size of aphids was counted. [ Results ] With the increase of EβF dose, the number of escaping aphids in 3 min increased significantly, while the percent of winged adult aphids increased but the population size of aphids decreased significantly after treatment, and the repelling effects increased significantly. EβF at the concentration of 200 ng/μL and 〉1600 ng/μL caused significant decrease in the population size of aphids （P 〈0.05 ）. Choice behavior bioassay with Y-tube olfactometer indicated that the 3rd instar nymphal aphids were significantly repelled by ≥600 ng/μL EβF （P 〈0.01）. The percent of winged adult aphids in treatments with ≥600 ng/μL EβF was significantly higher than that in the control （P 〈0.01 ）. The aphid population growth was significantly inhibited by ≥400 ng/μL EβF （P 〈 0.01 ）, but there was no statistical difference between treatments with 400 ng/μL and 600 ng/μL EβF. [ Conclusion] We so proposed 600 ng/μL EβF in paraffin oil as the low threshold concentration of EβF for repelling S. avenae.