中红侧沟茧蜂对不同龄期棉铃虫幼虫及其为害棉株的趋性反应

Responses of Microplitis mediator Haliday(Hymenoptera:Braconidae) to different instar larvae of Helicoverpa armigera Hbner(Lepidoptera:Noctuidae) and damaged cotton plants

研究中红侧沟茧蜂Microplitis mediator Haliday对棉铃虫Helicoverpa armigera Hbner幼虫及其为害棉株的趋性行为,可为高效应用中红侧沟茧蜂控制棉铃虫提供理论依据。本研究在实验室内以中红侧沟茧蜂雌蜂、1～5龄棉铃虫幼虫及其为害棉花植株(去虫或未去虫)为试验材料,采用"Y"型昆虫嗅觉仪测定了中红侧沟茧蜂雌蜂对1～5龄棉铃虫幼虫及其为害棉株的趋性行为反应。结果表明:中红侧沟茧蜂对3龄、4龄和5龄棉铃虫幼虫均没有明显的趋向行为反应,1龄和2龄棉铃虫幼虫对中红侧沟茧蜂有显著的引诱作用。此外,1～5龄棉铃虫幼虫为害后去虫棉株与健康棉株均对中红侧沟茧蜂有吸引作用。在未去虫的处理中,虫害诱导棉株比健康植株更能吸引中红侧沟茧蜂,与健康植株差异显著,而且不同龄期棉铃虫幼虫为害处理间差异较大,对中红侧沟茧蜂引诱作用的相对顺序为:5龄为害植株>2龄和4龄为害植株>1龄和3龄为害植株(2龄和4龄为害处理间差异不显著;1龄和3龄为害处理间差异不显著)。本研究结果可为中红侧沟茧蜂在生物防治上的应用提供一定的理论指导和实践依据。

Studying the responses of Microplitis mediator Haliday to different instar larvae of Helicoverpa armigera Hbner and damaged cotton plants could supply the theoretical basis for effectively applying M. mediator to control cotton bollworm （CBW）. In this study,responses of female M. mediator wasps to different instar larvae of CBW and damaged cotton plants were measured by using Y-shaped olfactometer in laboratory. Results showed that CBW larvae of the 3rd,4th and 5th instars had no significant attraction to M. mediator,while CBW larvae of the 1st and 2nd instars had significant attraction. Among the behavioral responses of M. mediator to cotton plants damaged by different instar larvae of CBW,we found that both cotton plants damaged by CBW larvae and the healthy ones （the control） could strongly attract wasps. In tests with no larvae removed,M. mediator wasps had a significantly higher preference for damaged cotton plants plus CBW larvae than for the control,but there were notable differences in attraction among different instars,and the relative selective preference order was as follows：plants infested by 5th instar larvae of CBW 〉plants infested by 2nd and 4th instar larvae of CBW〉 plants infested by 1st and 3rd instar larvae of CBW. The results may provide some theoretical guidance and practical basis for application of M. mediator in biological control strategy.