Ecological And Biological Characteristics Of Arge Similis Vollenhoven(Hymenoptera:Argidae)

Arge similis Vollenhoven is a serious pest of Ericaceae plants,and the study about it is less neither in China or in other countries.The determination of A.similis larvae instars is the crucial foundation for further research of the pest,such as the biological characteristics,the occurrence,the forecast and prevention.Older inatsr larvae or pupae were collected from outside to the laboratory.I used laboratory maintained healthy larvae to determine the size of various instars.Measurement was done about the head capsule width,body width,and body length.Dyar rule and Crosby rule were used to analyze the data.Results showed that both male and female larvae can be divided into 5 instars.The head capsule width was the most important criterion for determining the instar,and the body width and body length can be used as suppliementary criteria.Observations on mating behavior showed that females calling occurred from 7.5-9h(13:30-15:00)in photophase,and the peak was on 8.5h(14:30)in photophase.Calling rate and times decreased with age.Mating happened mainly on the first three days,and mating duration time also decreased with age.Susceptibility of A.similis larvae and pupae to brief exposure of high tempureatures was tested at 35,38,and 41℃,and were treated for 1 and 4h.The impact to larvae head width and body length was little,it was bigger to older instar larvae when compared to 1st instar larvae.The larvae mortality rate was positively correlated with the temperature and treatment time.At 41℃ for 4h,the 1st instar larvae and older instar larvae suffered 81.67% and 96.67% mortality,respectively.After moved to normal temperature(27℃,as control),the mortality rate also rised.The mortality rate of 35℃ for 4h was 88.24%,and nearly all old larvae of 41℃ dead.High tempetrature treatment caused early pupation and delayed adult emergence.To investigate the impact of larvae group size on the growth and survival of A.similis,I placed 1,5,10,15 and 20 larvae per container.Results showed that 1 larva per container had the shortest papue duration while the 10 larvae per container size had the longest.The pupation rate of 1 and 5 larvae were 100%,for 20 larvae was 98.33%,while those of the other group sizes were under that.The emergencr rates were not significantly different among group sizes.Volatiles from Rhododendron pulchrum Sweet leaves were collected using dynamic headspace collection and analyzed using GC-MS.A total of 15 compounds were identified.The main compounds were: benzaldehyde,4-ethyl-(18.56%),ethanone,1-(4-ethylphenyl)(6.25%),isophthalaldehyde(7.78%),ethanone,1-(3,4-dimethylphenyl)(3.40%).The compounds which caused female EAD responses were: 1-ethyl-3-methyl-benzene,1,2-diethyl-benzene,1,4-diethyl-benzene,and 1-ethenyl-3-ethyl-benzene.