Geographic Variations Of Sex Pheromone Components In Pine Caterpillar Moths, Dendrolimus Puncatus And Dendrolimus Kikuchii (Lepidoptera: Lasiocampidae)

The pine caterpillar moths,Dendrolimus kikuchii and D.punctatus(Lepidoptera:Lasiocampidae),have large geographic distribution range in south of Yangtse River,which are important conifer defoliators in southern China.In order to unveil the sex pheromone responses divergences of different grographical populuations and develop a geographical-specific pheromone lure for more sensitive D.kikuchii and D.punctatus monitoring and control,we focus on the geographic variation analysis of sex pheromone quantity,blend ratio,antennal sensitivity,and biological activity of this two pine caterpillar species,including three populations of D.kikuchii from Hunan,Jiangxi,and Yunnan Provinces,six populations of D.punctatus from Jiangxi,Hunan,Guizhou,and Guangxi,as well as heavy and light damage levels of that from Hongan district of Hubei.Sex pheromones from different populations mentioned above were analyzed by means of Gas chromatography(GC),GC-mass spectrum(MS),Electroantennographic recording(EAG),and field behavioral assays.The major research results are as follows.1.GC analyses of virgin female glands extracts of D.kikuchii demonstrated that(5Z,7E)-5,7-dodecadien-1-yl acetate(Z5,E7-12:OAc),(5Z,7E)-5,7-dodecadien-1-ol(Z5,E7-12: OH)and(5Z)-5-dodecenyl acetate(Z5-12:OAc)were present in all three populations from Hunan,Yunnan,and Jiangxi moth specimens.On average,all populations had a similar and abundant quantity of Z5,E7-12:OAc as well as trace amounts of Z5,E7-12:OH and Z5-12:OAc,the blend ratio and quantities in three populations existed relatively small differences.The three components with a blend ratio of 100:10:25 or 100:10:10.Analysis by EAG test,The proportion of 3 kinds of sex pheromone components showed best EAG reaction in 100:10:25of Hunan population,Yunnan population is 100:10:10,and Jiangxi population is 100:10:10 or100:10:25.Inter forest biological test showed that the 3 sex pheromone components in Hunan population were best in the proportion of 100:10:25,while the Yunnan population and Jiangxi population were 100:10:25 or 100:10:10.2.GC analyses of virgin female glands extracts of D.punctauts from 5 populations demonstrated that Z5,E7-12:OAc,Z5,E7-12:OH and(5Z,7E)-5,7-dodecadien-l-yl propionate(Z5,E7-12:OPr)were detected in different populations of D.punctauts.The contents of sex pheromone components showed relative significant variations in different populations from Jiangxi,Guizhou,Hunan,Guangxi and Hubei provinces,with small variations in different populations from the same collected sites,and the only very weak variations in two populations with heavy-and light-damaged levels from Hong'an district,Hubei provinces.The variation trend of the ratios of the three major sex pheromone components is the same as their contents.The dose-response of male moth antennae from different populations to three sexual pheromones with stimulus loads from 1ng to 10?g showed that the EAG abundance increased with the increasing stimulus loads.The antanne of male moths from light-damaged areas were more sensitive to the three pheromone components than that from heavy-damaged areas.Qili pupulations which was from light-damaged levels and Xinghua populations that in heavy-damaged levels in Hong'an,Hubei province all showed the largest EAG responses to the blend ratio 100:80:40 of the three pheromone components and their responses showed no statistically difference.In the field behavioral tests,the lures formulated with the blend ratio100:80:30 of the three pheromone components demonstrated the best behavioral activity and tap catches in heavy-damaged areas were larger than that in light-damaged areas.The three sex pheromone components in D.kikuchii collected from Hunan,Yunnan,and Jiangxi are Z5,E7-12:OAc,Z5,E7-12:OH,and Z5-12:OAc,which showed minor differences in quantity and ratio.As for D.punctatus,Z5,E7-12:OAc,Z5,E7-12:OH,and Z5,E7-12:OPr are its sex pheromone components,which showed larger differences in ratio from different populations.It may be that in the process of spreading,the pressure of sex selection is weak,but the geographical factors,such as temperature,humidity and topography,still have different effects on the release of the sex pheromone of the female moth of D.kikuchii and the induction of the sex pheromone induced by the male moth.According to the environmental and geographical factors of three regions in Puer,Hunan,Chenzhou and Jiujiang of Jiangxi,the higher the temperature and humidity and the undergrowth of the bottom of the forest layer,themore advantageous to the survival and reproduction of D.kikuchii.The subtle changes in sex pheromone quantities and blend ratios in different geographic populations of D.kikuchii and D.punctatus indicated that some minor genetic variation but did not form completely independent groups might be related to geographic distribution range,hosts,and man-made interference.