Preliminary Exploration On Influence Factors Of Host-searching By Fopius Arisanus(Sonan)

From the point of view of insect behavior,this study discussed the factors affecting the host search of Fopius arisanus,and provided the basis for the field application of the parasitoid,laying a foundation for improving the biological control of the parasitoid.On the one hand,by observing and studying the biological habits of Fopius arisanus.Found out the factors that affect the parasitism rate and the sex ratio,which provide a theoretical basis for the field application.The second aspect is to explore the role of host fruit in the search for hosts of Fopius arisanus.Third,by observing the behavioral response of Fopius arisanus to the volatile substances of 10 host plants,we find out the chemicals that can attract them.To further explore the role of host plant volatile substances in the search for hosts of Fopius arisanus.The results are as follows:(1)Studies on spawning behavior and parasitic rate of Fopius arisanus showed an obvious circadian rhythm of spawning behavior,and the peak period of daily egg production was 13:00-1800:00.After 10 days to 20 days,the spawning efficiency was higher,and the female number of offspring was higher than that of male,and the parasitic rate of 15 days was the highest,and the sex ratio was the highest in 10 days.The effect of host egg age on parasitic rate of Fopius arisanus was not obvious.The parasitic rate of Fopius arisanus on host fruit of small fruit flies is Pyrus spp,Psidium guajava,Chaenomelessinensis koehne,Citrus reticulata Blanco,and the sex ratio to offspring is also related to host fruit.The study shows that Psidium guajava is the most suitable for laboratory inoculation of Fopius arisanus.(2)Behavioral responses of Fopius arisanus to four host fruits.The results of Y-type olfactory instrument showed that healthy,mechanically damaged and host fruits which were damaged by Bactrocera dorsalis had significant seductive effects on the Fopius arisanus.In addition,when the host fruit is harmed by the fruit of the Bactrocera dorsalis,the inducement will be enhanced.The selective response to infected fruit was closely related to the time of host fruit damage.Pyrus spp and Citrus reticulata Blanco had the strongest seductive effect after 1 day,Mangifera indica and Amygdalus persica had the strongest seductive effect after 3 days.Citrus reticulata Blanco had the effect of avoiding the Fopius arisanus after 5 days of infection.(3)Behavioral responses of Fopius arisanus to volatile substances of host fruits.The results of six-choice olfactometer showed that the behavioral responses of female and male parasites to 10 different concentrations of volatile substances in host plants were very different.Parasitoids may exhibit different behavioral responses to different concentrations of the same volatile substance.When the concentration of trans-Farneso was 10-1,it was the most attractive to males of Fopius arisanus,10-2 of which was the most attractive to females of Fopius arisanus.Benzaldehyde has a certain tendency to avoid female and male parasites of Fopius arisanus.