| Plant volatiles play an important role in plant-insect communication,and volatiles from non-host plants can affect multiple behaviors of insects.The Yunnan shoot borer,Tomicus yunnanensis(Coleoptera: Scolytidae),is one of the most important pest,which are indigenous shoot-feeding beetles that attack the Pinus yunnanensis in Southwest of China.Currently,using plenty of chemical pesticides to control the population of pests,which makes the residue,resistance and resurgence effects more and more serious.So,this study used Alnus ferdinandi-coburgii as materials,obtained the active substance of plant volatiles by headspace dynamic method,GC-MS,GC-EAD,and behavioral tests.And used odor active substances to interfere with ovarian development and post-embryonic development of Tomicus yunnanensis.The main results were as follows:(1)Processing-morphology Change for Ovarian Development and larva change in Tomicus yunnanensisThe female reproductive system of Yunnan shoot borer is located in the inferior toward the lateral part of the alimentary canal at the fourth abdominal segment.It consists of a pair of ovaries and two short lateral oviducts,a common oviduct,a spermatheca and two accessory glands.The ovaries have four tubular ovarioles.The terminal filaments extended from the anterior end of each ovariole can adhere to the internal tegument or fat body.According to the morphological changes,the ovarian development was divided into five grades,including transparent period(grade I),terminal elongation period(grade II),previtellogenic(III grade),vitellogenic eggs(grade VI),and ovipositing period(grade V).Each grade of ovarian development could last less than 1 to 4 month,and show a closely related to the nutrient acquisition.The length of ovariole grows slowly in the previous and middle and rapidly in late grades,but the width of ovariole grow rapidly in the previous and late grades.The whole size of ovary increased rapidly with a power-law dependence.At the same time,the width of head capsule of this larvae was used as an indicator to divide the larvae development of Tomicus yunnanensis,the larvae development was divided into three instars,including newly hatched larvae,second instar larvae and third instar larvae.(2)Obtaining the odor-active substance of Alnus ferdinandi-coburgiiWe got 45 kinds of compounds in plant volatiles of Alnus ferdinandi-coburgii,with terpenoids and ketones as main components.GC-EAD analysis confirmed that(Z)-Hex-4-en-1-ol,trans-2-Hexen-1-ol,(1R)-(+)-alpha-pinene,4-Ethylacetophenone and 4-Allylanisole was the important compound,which could cause the antennaeresponse of female insects.Among these compounds,4-Allylanisole had the highest antennae response.Behavioral assays showed that(1R)-(+)-alpha-pinene and 3-carene could attract female insects,and beta-Pinene,(Z)-Hex-4-en-1-ol,trans-2-Hexen-1-ol,4-Ethylacetophenone and 4-Allylanisole could repel female insects.But when3-carene,(1R)-(+)-alpha-pinene and beta-Pinene exist simultaneously,beta-Pinene did not show obvious repellent effect.(3)Effects of the odor-active substance of Alnus ferdinandi-coburgii on the ovary and post-embryonic development of Tomicus yunnanensis.The length of the main galleries of female adults and sub-galleries of larvae were increased after disturbance by odor active substance.The number of eggs did not show significant changes.However,when the odor-active substance was present,the body length and body weight of the larvae of Yunnan shoot borer increased.At the same time,the non-host plant volatiles could reduce the synthesis of yolk protein in female adult larvae of Tomicus yunnanensis.In this study,ovarian development and larva change were confirmed.Defined the active ingredients in the volatiles of Alnus ferdinandi-coburgii.This results can provide scientific guidance for the development of management strategies for the control of this pest and the construction of mixed forest. |
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