Study On Antennal Sensilla Ultrastructure,and Screening Of Functional Compounds Of Ambrostoma Quadriimpressum Motschulsky

Ambrostoma quadriimpressum Motschulsky(Coleoptera: Chrysomelidae)is a major destructive forest pest.Currently,there is no effective and non-polluting method has been discovered to control this pest.This study focus on antenna sensilla ultrastructure were observed under scanning electron microscopy(SEM),moreover,through Electroantennography(EAG)and three groups of behavioural bioassays screen bio-functional volatiles for control of A.quadriimpressum.Electroantennography(EAG)tests with 13 candidate semiochemicals.(1)The observations of antennal sensilla ultrastructure:There is no sexual dimorphism founded in the segmentation and sensilla types of antenna in A.quadriimpressum.Antenna of female and male A.quadriimpressum is linear,and composed of 11 segments.This research found 8 class 13 types antennal sensilla,4 types of them are olfactory sensilla with pores in the cuticle of antennal sensilla,which were Sensilla basiconica 1(SB 1),Sensilla basiconica 2(SB 2),Sensilla trichodea 2(ST 2)and grooved peg(GP).9 types other bio-functional sensilla were identified including Sensilla chaetica 1(SC 1),Sensilla chaetica 2(SC 2),Sensilla trichodea 1(ST 1),Sensilla trichodea 3(ST 3),Sensilla trichodea 4(ST 4),Styloconic sensilla(SS),Sensilla cavity(SCa),B?hm bristles(BB)and Sensilla Coeloconic(SCo).Distribution of antennal sensilla are different between 11 segments.3 types of antennal sensilla are distributed throughout theantenna,including Sensilla chaetica 1(SC 1),Sensilla chaetica 2(SC 2)and Sensilla trichodea 3(ST 3),quantityof Sensilla trichodea 3(ST 3)is the most.There are 5 types of antennal sensilla that females’ amount of types antennal sensilla significant(P< 0.05)more than males’,including Sensilla chaetica 2(SC 2),Sensilla trichodea 1(ST 1),Sensilla trichodea 2(ST 2),Sensilla trichodea 3(ST 3)and Sensilla basiconica 1(SB 1).(2)The EAG response results of A.quadriimpressum to exogenous volatiles:At concentration of 10μg/μl indicated,5 volatiles(cinnamaldehyde,phenol,methanol,Dimethyl naphthalene,1-undecene)elicited the significant(p< 0.01)EAG responses in females,and 4 volatiles(Cinnamaldehyde,Di-n-octyl phthalate,Dimethyl naphthalene,Phenol)elicited the significant(p< 0.01)EAG responses in males.Cinnamaldehyde elicited the highest EAG responses in both males and females.The EAG response results of A.quadriimpressumare differences between different doses of the same compounds.Both females and males EAG responses to cinnamaldehyde rose with increasing stimulus concentration.(3)The behavioural bioassays results of A.quadriimpressum:Screening of semiochemicals experiment showed that cinnamaldehyde had substantial repellent effects on both male and female at 1 μg/μl.Y-tube olfactometer experiment showed that cinnamaldehyde exhibited significant(p< 0.05)repellent effect to female at 1 μg/μl,and rate of repellent was 70%.Cinnamaldehyde exhibited significant(p< 0.05)repellent effect to male at 10μg/μl,and rate of repellent was 70%.Foraging choices under the influence of cinnamaldehyde experiment showed that cinnamaldehyde exhibited significant(p< 0.05)antifeedants effect at 10μg/μl,rate of food refusal was 90%.Because of A.quadriimpressum’s monophagy,it was most probably correlated with the host specificity.This study provided theoretical basis for the exploration of environmentally-friendly chemical control methods.