| Ancylis sativa Liu (Lepidoptera: Tortricidae), is one of the most important pests of Chinese jujube tree (Ziziphus jujube Mill).In recent years, it caused serious damage to Chinese jujube tree in Shaanxi and Shanxi province, and sometimes even cause destruction. In this paper we focused on the plant volatiles interact with the insect. Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS), the electroantennogram recording technique (EAG), insect behavior method and other research methods were used to confirm the mechanism of host selection of A. sativa and host volatiles effect. Whilemean, finding the attraction and aversion composition of volatiles to A. sativa is intended to provide scientific and theoretical basis for the effective control on the damage by A. sativa. The main results showed as follows:The analysis of the volatiles composition of branches and shoots in different physiological status from Ziziphus jujuba Mill.cv.Muzao by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) showed that the volatile compounds comprised mainly a range of terpenes and esters, secondly alcohol. The volatiles composition of branch of Z. jujuba Mill.cv.Muzao consisted of 9 compounds, and shoots 24 compounds. The healthy, artificial and infested damage shoots are detected difference in composition and ratio of volatiles. 4-hexen-1-ol, acetate is an herbivore-induced plant volatile which is emitted rapidly after leaf damaged and may attracts natural enemies. The results of olfactory experiment indicated that the artificial damage shoot showed significant repellency against moth of A. sativa while the shoots whatever healthy and infested damage showed attraction.The volatile compounds of tender leaves from Z. jujuba Mill.cv.Muzao and Ziziphus spinosa were identified in the germination stage by SPME and GC-MS, the results showed that Z. jujuba Mill.cv.Muzao and Z. spinosa were no significantdifferencese; however, the relative content was slightly different. EAG response of A. sativa on Z. jujuba Mill.cv.Muzao and Z. spinosa showed that both of the host plants had strong response in millivolts, and the absolute response in millivolts of the female antenna is general substantially higher than the male on the same host. Oflactory responses showed that A. sativa were strongly attracted by Z. jujuba Mill.cv.Muzao, and the females were attracted more strongly than the males, but they were not attraction by Z. spinosa. The test of insect oviposition showed that more eggs were obtained on the Z. jujuba Mill.cv.Muzao than on the Z. spinosa in the laboratory. Our results showed that the preference of A. sativa was Z. jujuba Mill.cv.Muzao. Furthermore, plant volatiles played a great role in oviposition, as in the A. sativa selection for plant host.The experiment under controlled laboratory conditions showed that oviposition and behavioral responses of A. sativa were different under plant volatile stimulus or not. Compared with other generations, first generation laid most eggs. In different developing period of Z. jujuba Mill.cv.Muzao, A. sativa laid most eggs in young leaf stage. Oflactory responses showed that overwintering and first generations of A. sativa made stronger selection responses, whilemean, selection responses of A. sativa were also stronger in the flower stage or before flower stage.The external morphologies of the antennal sensilla on the antennae of both female and male adults of A. sativa were observed using scanning electron microscopy. The antennae of both sexs of A. sativa were filiform in shape, consisting of the scape, pedicel and 49-52 segments of flagellomeres, and located between the compound eyes. Sensilla trichodea, two types of sensilla chaetica, sensilla coeloclnica, sensilla squamiformia, sensilla styloconica, b?hm bristles and three types of sensilla auricillica were observed on the female and male antennae. Two type of sensilla chaetica occurred only on the female antenna. The numbers of sensilla trichodea on the male were significantly greater than those of the female. However, the numbers of sensilla coeloclnica of the female were significantly more than those of the male.EAG responses of A. sativa to host volatile compounds were recorded. The results were significantly different among Virgin female, male and mate female in EAG responses. Five of the 18 compounds can elicit strong electrophysiological response, and butyl acetate had highest in millivolts, secondly was Trans-2-hexen-1-ol, Trans-3-hexen-1-ol, Cis-3-hexenyl acetate and Trans-2-hexen-1-al to A. sativa. EAG responses of the most of volatiles from low to high concentration to A. sativa showed an upward trend. Oflactory responses showed that trans-2-hexen-1-ol, trans-3-hexen-1-ol, cis-3-hexenyl acetate, trans-2-hexen-1-al, butyl acetate andα-Phellandrene were all significant repellency in host selection of A. sativa at the highest concentration (100μg/μL). But butyl acetate, ocimene and trans-2-hexen-1-ol were the most significant attractive to A. sativa at the 10μg/μL concentration. 1μg/μL concentration was perfect in the lowest concentration of the most compounds in behavioral responses of A. sativa. There were no significant differences on treatment and control among the lower three concentrations (0.1μg/μL, 0.01μg/μL, 0.001μg/μL). Thus, our results showed that trans-2-hexen-1-ol, trans-3-hexen-1-ol, cis-3-hexenyl acetate, ocimene, butyl acetate played important roles in host recognition in A. sativa. |
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