Extraction And Identification Of Sex Pheromone Of Ectropis Obliqua Prout And Correlative Studies On Its Biology

Tea looper, Ectropis oblique Prout (Lepidoptera, Geometridae, Ennominae) is aserious defoliator of tea bushes Camellia sinensis in southeast of China. Outbreakpopulations could defoliate all the bushes completely and rapidly. In China, excessiveusing of organosynthetic pesticides to control this pest had lead to environmental pollution,development of resistance and undesirable pesticide residues in made tea. Efforts are beingdirected towards developing compatible management strategies and methods for anintegrated approach to pest control. The applying of sex pheromones to control tea looperis a practical approach.Based on the theory of insect chemical ecology, we systematically studied the mainmorphology and biology of tea looper, we also carried out work including identification,synthesis of sex pheromone of tea looper by means of environmental scanning electronmicroscope (ESEM),electroantennogram (EAG), gas chromatography-electroantennogram(GC-EAD), gas chromatography-mass spectrometry (GC-MS), organic synthesis and fieldtrapping tests. We aimed to prove up the tea looper’s sex pheromone communicationsystem and its variety, and quest for a new method to control it with sex pheromone.The main study results as the follows:1. Studies on the biology of the tea looper. Biological characteristics and sexualbehavior of the tea looper were observed continuously. Results showed that the ratio offemale to male adults was1:1.22. The emergence mainly occurred from18:00to2:00and copulation mainly occurred from21:00to24:00with the peak at23:00. Female mothcan spawn several times. So the best time to gather sex pheromone is the second day’snight (22:30) after emergence.2. Observation of the ovipositor and antenna of tea looper with ESEM. The resultsshowed that the surface of Intersegmental membrane on the ovipositor distributed papillae,which is the sex pheromone secretion site. There are four types of sensilla on the tealooper’s antenna, incuding Sensilla trichodea, S styloconica, S cheatica and Ssquamiformium. The Sensilla trichodea was most numerous, which are the main sexpheromone-recepting senesilla. There are differences in amount and type of antennalsensilla between female and male.3. Mating strategy and its effect on EAG response to sex pheromone. The effect ofreproduction behavior of tea looper was studied. Results suggested that male was capable of mating several times with females, while vast majority of females mate only once.Mated males can live longer than virgin male. But mating did not influence on the lifeexpectancy of female. Mating did not affect EAG response of male to sex pheromone.Males mated past0,1,2,3,4days remained the same response to sex pheromone as virginmale. While EAG response of male to mated female’s sex gland extract decreasedsignificantly.4. The extracting and identification of active components from sex pheromone gland’sextract. Two active components were obtained from the female sexual gland extracts withhigh EAG value. And this two components were identified as z,z,z-3,6,9-Octadecatriene(Z3Z6Z9-18Hy) and z,z-3,9-6,7-Epoxy-octadecadiene (Z3Z9-6,7epo-18Hy) by means ofGC-MS. The content of each component is1.25±0.41ng/female、0.79±0.48ng/female.The percentages of Z3Z6Z9-18Hy/Z3Z9-6,7epo-18Hy in sexual gland extracts fromindividual females were about1.89.5. Chemical synthesis of sex pheromones. The target product, Z3Z6Z9-18Hy wasobtained successfully from methyl linolenate through Carboxylation and decarboxylation.Purity was98.45%。Then, Z3Z9-6,7epo-18Hy was yield through epoxidation with thepurity of98.2%.6. The EAG test to sex pheromone and standard chemicals. EAG values wereobtained to the standard components. A blend of Z3Z6Z9-18Hy and Z3Z9-6,7epo-18Hy ata ratio of2:8,5:5elicited the higher EAG response at7.816±0.254mV and7.650±0.201mV, respectively. The dosage response curve of each component roughly took an―S‖shape.7. Field trapping test. The results of trapping were consistent to the EAG results.Single component captured only a few male moths. Traps baited test with blend ofZ3Z6Z9-18Hy and Z3Z9-6,7epo-18Hy at different ratio show that at a ratio of2:8produced the highest trap captures and the average captures was35. In the dosage test, thehighest capture numbers was at10μg.We extracted the entire components of tea looper’s sex pheromone for the first timeand the chemical structures were identified successfully. We confirmed that the activecomponents of the sex pheromone and obtained the mixture of the best lure through EAGresponse and field trap test. This study not only enriched the research field of insect sexpheromone, but also offers an efficient, nontoxic, pollution-free, pollution-free methods tomonitor and control the population densities of tea looper.