The Developmental Performance Of Dastarcus Helophoroides Larvae On Zophobas Atratus

Dastarcus helophoroides is an important ectoparasitic natural enemy insect found to control longicorn pests up to now.It has been released into the forest to control target pests after being artificially propagated in large quantities and achieved good results.D.helophoroides is a parasitic enemy insect which belongs to coleoptera.And it mainly searchs for hosts by larvae and completes the trapping parasitism.However,the parasitic selection and reproduction strategy of this parasitic larvae are still unclear.This study intends to establish a parasitism system of " alternate host chrysalis-parasitism larva",determine the effects of density,age,host weight,parasitism state and pupation age of parasitism larva on its development performance and suitability of eclosion adult,and clarify the effects of intraspecific competition and physiological state of parasitism larva on parasitism selection and reproduction strategy,so as to provide scientific basis for improving propagation efficiency of parasitism larva and enriching parasitism strategy of parasitic natural enemy insect larva.The main results are as follows:1.By comparing the hatching conditions of the eggs under different temperatures,the results show that the hatching rate of the eggs is the highest at 25 ?,reaching 69.55% and the hatching peak of the eggs is earlier and the hatching amount of the eggs at the peak is the highest at 30 ?,reaching 101 eggs.2.By inoculating different numbers of D.helophoroides larvae on barley pupae with different weights,the results showed that the inoculation density was the most important factor affecting the larval development and adult fitness.The larval stage,cocoon stage and number of cocoons were positively correlated with the host weight and inoculation density,while the weight,body length and body width of the adult were negatively correlated with the inoculation density.3.By inoculating different-day-old larvae of D.helophoroides on different-day-old alternative hosts,the results showed that with the increase of the host's age,the larval stage of D.helophoroides increased significantly,and the length,body width and body weight of eclosion adults decreased significantly.The cocoon stage and eclosion rate were significantly different among different treatments,but there was no obvious rule.The larval stage of D.helophoroides is significantly prolonged with the increase of the larval age,and the cocoon forming rate is obviously negatively correlated with the larval age,but the larval age of D.helophoroides has no significant influence on its cocoon stage and adult emergence rate.The body length,body width and the weight of the single-headed adults were significantly different among the treatment groups with the increase of the larval age.The total weight of the adults was negatively correlated with the larval age.4.By inoculating the parasitized alternate host with the larva of D.helophoroides,the results showed that with the increase of parasitization time,the parasitization success rate of D.helophoroides larvae showed an overall upward trend.Among them,the highest success rate of parasitization was 76.67% when the parasitized larvae were inoculated on the alternate host for 2 days.5.By comparing the utilization rate of host resources of D.helophoroides larvae under different conditions,the results showed that when the larval age is 1 day,the utilization rate of host resources of D.helophoroides is the highest,75.55% and the utilization rate of host resources of D.helophoroides larvae had a negative correlation with the day age of D.helophoroides larvae,but had little correlation with the day age of alternative hosts.By analyzing and comparing the effects of inoculation density,larval age and alternative host age on parasitism efficiency,we found that,Inoculation density is the most important factor that affects the parasitism efficiency of D.helophoroides.The 1st instar larvae are the best life state of D.helophoroides larvae.They prefer to parasitize fresh and newly pupated alternate hosts.The utilization rate of host resources is the highest.The development performance of larvae and the fitness of adults are also significantly better than other treatment groups.The results of this study have great reference value for the efficient breeding of D.helophoroides with alternate hosts.