Abstract:
Huanglongbing (HLB), a devastating citrus disease caused by Candidatus Liberibacter asiaticus, is efficiently vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). Tamarixia radiata (Waterston) plays a crucial role as an ectoparasitoid, preying on D. citri nymphs. By collecting and identifying headspace volatiles from fifth instar nymphs of D. citri using a gas chromatograph-mass spectrometer (GC-MS), we obtained a collection of 9 volatile compounds. These compounds were subsequently chosen to investigate the electrophysiological and behavioral responses of female T. radiata. At a concentration of 10 μg/μl, 9 compounds were compared with cis-3-hexen-1-ol (control), resulting in trans-2-nonenal inducing the highest relative electroantennogram (EAG) value, followed by hexanal, heptanal, n-heptadecane, tetradecanal, n-tetradecane, n-pentadecane, 1-tetradecanol, and 1-dodecanol. The top 5 EAG responses of female T. radiata to these compounds were further investigated through EAG dose-response experiments. The results showed positive dose-responses as concentrations increased from 0.01 to 10 μg/μl. In Y-tube olfactometer bioassays, female T. radiata exhibited a preference for specific compounds. They were significantly attracted to tetradecanal at a concentration of 10 µg/µl and trans-2-nonenal at 0.01 µg/µl, while no significant attraction was observed toward hexanal, heptanal, or n-heptadecane. Our report is the first to demonstrate that volatiles produced by D. citri nymphs attract T. radiata, which suggests that this parasitoid may utilize nymph volatiles to locate its host.
摘要:
黄龙冰(HLB),由亚洲念珠菌引起的毁灭性柑橘病,被亚洲柑橘木虱有效地引导,金雀科(半翅目:Liviidae)。华士顿(Waterston)作为外寄生虫起着至关重要的作用,捕食D.citri若虫.通过使用气相色谱-质谱仪(GC-MS)从D.citri的五龄若虫中收集和鉴定顶空挥发物,我们获得了9种挥发性化合物的集合。随后选择这些化合物来研究雌性T.radiata的电生理和行为反应。浓度为10μg/μl时,9个化合物与顺式-3-己烯-1-醇(对照)比较,导致反式-2-壬烯醛诱导最高的相对触角图(EAG)值,其次是己醛,庚醛,正十七烷,十四烷醛,正十四烷,正十五烷,1-十四醇,和1-十二烷醇。通过EAG剂量反应实验进一步研究了雌性T.radiata对这些化合物的前5个EAG反应。结果显示,随着浓度从0.01μg/μl增加到10μg/μl,阳性剂量-反应。在Y管嗅觉仪生物测定中,雌性T.radiata表现出对特定化合物的偏爱。它们被浓度为10µg/µl的十四烷醛和浓度为0.01µg/µl的反式-2-壬烯醛显著吸引,虽然没有观察到对己醛的显著吸引力,庚醛,或者正十七烷.我们的报告是第一个证明由D.citri若虫产生的挥发物吸引T.radiata,这表明这种寄生虫可能利用若虫挥发物来定位其宿主。