| Although long-time insect evolution process,insects need to form a complicated olfactory system to recognize chemical information closely related to their life demands in complex surroundings and further to accomplish a serious of significant behaviors such as mating behavior and oviposition selection.Protaetia brevitarsis Lewis(Coleoptera: Scarabaeidae),is one of the most economically important pests in agriculture and forestry all over the world.Helicoverpa armigera Hübner(Lepidoptera: Noctuidae: Heliothinae),is a worldwide agricultural and forestry pest.In order to explore green and pollution-free management tactics in modern agriculture,we studied on the electroantennogram response of P.brevitarsis to its active component of sex pheromone,and the effects of different feeding experiences on the oviposition behavior of H.armigera,the oviposition preference of H.armigera and the plant volatiles that might induce the oviposition preference on cotton under four conditions(healthy,mechanical wounding,damaging and damaged),developing environmentally friendly and efficient sex attractants for P.brevitarsis,plant originated attractants for H.armigera.The results of this study may provide scientific basis for the green management of P.brevitarsis and H.armigera.The behavior can be divided into four steps,including courting,mounting,copulating and post-copulatory guarding.No courting behavior was observed in the adults aged 1-5 days.Courting and copulating behaviors occurred in the adults aged over 10 days,and peaked in the adults aged 30-35 days.The courting percentage in the adults aged 10-15 days was significantly lower than those in the adults aged 20-25,30-35,and40-45 days.The mating rates in the adults aged 30-35 and 40-45 days were significantly higher than those in the adults aged 10-15 and 20-25 days.Moreover,daily mating mostly occurred during 11:00-14:00,and no mating behavior was observed at night.The duration of copulation ranged from 1 to 12 min,with an average of 7.47 min.53.85% of the observed copulation lasted for 6-9 min.These results indicate that the mating behavior of P.brevitarsis adults has an obvious circadian rhythm,and there exists no significant influence of supplemental feeding on mating success.Based on the mating behavior of P.brevitarsis,abdominal glands were excised from P.brevitarsis virgin females and placeed in a screw top vial containing solvent of Dichloromethane(HPLC)at the peak of mating behavior.The electroantennographic(EAG),gas chromatography coupled with electroantennographic detection(GC-EAD)and gas chromatography coupled with mass spectrometer(GC-MS)techniques were used to identify the physiologically active components from glands of P.brevitarsis.preliminary confirmed that the sex pheromone of P.brevitarsis is 2-(2-aminopropanoylamino).The oviposition behavior of H.armigera fed on artificial diet and cotton was different.The oviposition quantity of H.armigera fed on artificial diet was significantly higher than that fed on cotton,and the egg hatching rate of H.armigera fed on artificial diet was higher than that fed on cotton,but there was no significant difference between the two treatments.Organic adsorbent Porapak Q was used to collect volatiles of cotton under four states by headspace dynamic adsorption method.The headspace volatiles in four states were analyzed qualitatively and quantitatively by GC-MS.Seven compounds from the volatiles of healthy cotton were identified as p-xylene,o-xylene,D-limonene,1-decyne,nonanal,benzaldehyde,β-caryophyllene.Fourteen compounds from the volatiles of mechanical wounding cotton were identified as(-)-β-pinene,p-xylene,o-xylene,1-decyne,1,2-diethyl-benzene,1,4-diethyl-benzene,Z-3-hexen-1-ol,acetate,Z-3-hexen-1-ol,nonanal,E-2-hexen-1-ol,benzaldehyde,β-caryophyllene,naphthalene,1,4-methylphenyl-ethenone.Twenty-three compounds from the volatiles of damaging cotton were identified as α-pinene,camphene,hexanal,(-)-β-pinene,3-hexenal,D-limonene,E-2-hexenal,Z-2-penten-1-ol,acetate,1-decyne,β-ocimene,3-hexenoic acid,methyl ester,2-hexenoic acid,methyl ester,E-4,8-dimethylnona-1,3,7-triene,Z-3-hexenyl acetate,Z-3-hexen-1-ol,E-2-hexen-1-ol,Z-3-hexenyl iso-butyrate,E-Linalool oxide(furanoid),Z-3-hexenyl-α-methyl-butyrate,linalool,β-caryophyllene,1-(1,5-dimethyl-4-hexenyl)-4-methyl-3-Cyclohexen-1-ol,indole.Fourteen compounds from the volatiles of damaged cotton were identified as β-pinene,D-limonene,E-2-hexenal,1-decyne,β-ocimene,E-4,8-Dimethylnona-1,3,7-triene,Z-3-hexen-1-ol,acetate,2,6,11-trimethyl-dodecane,E-2-hexen-1-ol,E-2-methyl-butyl aldoxime,linalool,β-caryophyllene,phenylethyl alcohol,indole.Different states of cotton have their own unique volatiles.1,2-diethyl-benzene,1,4-diethyl-benzene,naphthalene,1,4-methylphenyl-ethenone were only present in the mechanical wounding cotton volatiles.Characteristic volatiles under damaging cotton were α-pinene,camphene,hexanal,3-hexenal,Z-2-penten-1-ol,acetate,Z-3-hexenyl isobutyrate,E-Linalool oxide(furanoid),Z-3-hexenyl-α-methyl-butyrate,1-(1,5-dimethyl-4-hexenyl)-4-methyl-3-Cyclohexen-1-ol.β-pinene,E-2-methyl-butyl aldoxime,phenylethyl alcohol were only present in the damaged cotton volatiles.The release amount of Z-3-hexenol in the damaging state of cotton was more than that in the mechanical wounding state,and there was a significant difference between the two states.The release amount of E-2-hexenol was the highest in cotton under the condition of damaging,followed by the release amount in the condition of damaged,and the least in the condition of mechanical wounding,but there was no significant difference in three states.The release amount of 1-decyne was the highest in the state of damaging,followed by mechanical wounding and damaged,and the least in the healthy state.The release amount in the state of damaging,mechanical wounding and damaged was significantly higher than that in the healthy state,but there was no significant difference in these three states.The release amount of E-2-hexenal in the damaging state was significantly higher than that damaged state.The release amount of(-)-β-pinene in damaging state was higher than that in mechanical wounding state,but there was no significant difference between them.The release amount of linalool and β-ocimene were higher than those damaged,but there was no significant difference.The release amount of β-caryophyllene was the highest under the condition of damaging,followed by damaged and mechanical wounding,and the least under the state of healthy.The release amount of it under the state of damaging was significantly higher than that under the other three states,but there was no significant difference in the release amount under the three states.The release amount of Z-3-hexenyl acetate was the highest in the damaging state,followed by the damaged state,and the lowest in the healthy state,and the release amount of Z-3-hexenyl acetate was significantly higher than that of the other two.There was no significant difference between the damaged and the healthy state.Both E-4,8-dimethylnona-1,3,7-triene and indole were released in the damage state,the release amount of E-4,8-dimethylnona-1,3,7-triene was higher in the damaging state than the damaged state,and the release amount of indole was higher in the damaged state than the damaging state,but there was no significant difference between them.H.armigera in the four states of cotton laying preference for cotton under the state of damaging.According to the results of principal component analysis(PCA)and cluster analysis(CA)of volatiles in four states,β-caryophyllene,E-2-hexenal,E-2-hexenol,and Z-3-hexenol generally exist in the volatiles of host plants of H.armigera,and the contents of these substances in the volatiles of damaging cotton are higher than those of other states,suggesting that these substances may be the key substances of host localization of H.armigera. |
