Study On The Attractive Effect Of Host Volatiles On The Dioryctria Rubella Hampson Females

In order to study attractive of the volatiles from the host of Pinus tabulaeformis,Dioryctria rubella Hampson was taken as the research object.Scanning electron microscope was used to observe antennal morphology,sensilla of females and males adults of D.rubella clear to microstructure of antennae sensilla of it.The chang of components and contents of volatiles in different parts of Pinus tabulaeformis before and after infested by gas chromatography-mass spectrometry(GC-MS)were analyzed,to screen out volatiles with significant differences,and configured them into different concentration and proportions into different mixtures.Electroantennogram(EAG)and Y-tube olfactometer were used to test the electrophysiology and behavioral responses of D.rubella adults to the main components of the volatiles from Pinus tabulaeformis.Scanning electron microscope was used to observe antennal structure of females and males adults of D.rubella.The results showed that a total of ten kinds of sensilla were discovered in it.Among them,Sensilla trichoidea(Ⅰ,Ⅱ)(ST),Sensilla chaetica(Ⅰ,Ⅱ)(SCH),Sensilla auricillica(SA),Sensilla coeloconica(SCO)and Bohm bristles(BB),were distributed on the antennal of females and males adults;But Sensilla tyloconica(SS)was only discovered on the female,and Sensilla campaniformia(CA)and Sensilla squamiformia(SQ)were only observed on the antennal of male.Most of the antennal sensilla existed in flagellum and lied on the upper and lower surfaces of the antennae.Sexual dimorphism of sensilla in the females and males adults was also apparent.The results of head space absoption and gas chromatography-mass spectrometry(GC-MS)showed that the main components of the infested cones and branches,uninfested cones and branches,infested branches,uninfested branches,infested cones and uninfested cones 6 different parts were roughly the same,but the content of each volatile matter was quite different.Among them,the relative content of 1R-α-pinene and D-limonene,increased after the plant materials were damaged by D.rubella.and the increase was larger.The relative content of β-pinene and β-caryophyllene decreased,and the decrease was more obvious.Myrene was a new substance existed only in the volatile matter of the damaged plant materials.All the 5 volatiles of the host caused different degrees of EAG and behavioral responses of D.rubella.Most of the them caused the strongest EAG response of mated and unmated females at the concentration of 1(v/v),but myrcene and β-pinene at 10-1(v/v)respectively caused the largest absolute value of EAG for mated females and unmated females.The absolute value of EAG of 1(v/v)1R-α-pinene for mated and unmated females reached the maximum in the five volatiles,with maximum EAG of 0.630 mV and 0.620 mV respectively.The second maximum relative EAG responses were observed both from mated and unmated that were 10-1(v/v)Myrene and 1(v/v)D-limonene.Paired T-test showed that only Myrene and D-limonene had a significant difference in EAG responses between mated and unmated females,however there was no significant difference for the other volatiles tested.1(v/v)1 R-α-pinene and 10-1(v/v)myrcene were the most substantial attractants to the mated females,and the attractive rate can reach 75.00%.1(v/v)1R-α-pinene had the strongest effect to the unmated females and the attractive rate reached 74.07%.Myrcene only had a significant effect on the mated females,while D-limonene only attracted the unmated females and reached a significant level.1(v/v)β-pinene had a significant repellent effect,in which the repellent rate for mated females was 76.92%,and unmated females was 71.42%.The results of the electroantennographic(EAG)and behavioral responses of mixtures showed that the strongest electrophysiological stimulation to the mated females was the mixture G.While the strongest stimulation for the unmated females was the mixture F.The absolute value of EAG of them were 1.573 mV and 1.426 mV respectively,compared with other mixtures,there were significant differences.The second was the stimulation of the mixture of E,H and I on the D.rubella females.The stimulation of the four mixtures of A,B,C and D were weak.The strongest attraction to mated females was mixture G,with an attractive rate of 79.31%.The most attractive to unmated females was mixture F,with an attractive rate of 78.60%.Both of which reached extremely significant levels.The mixture G,H,and I attracted both mated females and unmated females,and the attractant rate reached a significant level.The mixture A,C,and D had a weak attraction,and there was no significant difference from the control.