Effects Of Dastarcus Helophoroides Larval Density On The Degeneration Of Substitute Host Nutrition And Metabolism

Dastarcus helophoroides is an important parasitic natural enemy insect used to control large and medium-sized Cerambycidae pests.After obtaining a large number of eggs by acquiring the technical problem of the adult artificial fore legs,searching the replacement host with high fitness has become the key to obtaining a large number of D.helophoroides adult population.With the characteristics of moderate size,being rich in nutrition and low cost,pupaes of Zophobas atratus is one of the better substitute hosts for the D.helophoroides adults.However,during the process of artificial breeding of D.helophoroides,the parasitic efficiency decreases with the increase in brooding time of Zophobas atratus pupae.In this study,by inoculating different density D.helophoroides larvaes,founding the rule of the degeneration time of the D.helophoroides larvaes'thoracices and fore legs,and the morphological changes of the larvaes during the parasitism process.After the inoculation we measuring the activity of polyphenol oxidase,trehalose,alginate enzyme,reducing sugar,?-amylase,combined with its developmental performance,protein and glycogen,animal starch,so that the control effect of D.helophoroides on host was revealed,and because of these data the efficiency of using the substitute host to breed D.helophoroides was improved.The main results are as follows:1.The time of the degeneration time of the D.helophoroides larvaes'thoracices and fore legs in different densities.Microscopic was used in order to observe the degeneration of D.helophoroides'thoracices and fore legs.We found the D.helophoroides'thoracices and fore legs began to degenerated at the 2^nd3rd d after,and a few were at the 4^th d,and the peak of the degeneration was found at the 5^th d,and a few were completely degraded at the 4^th d^6th d.The density of D.helophoroides larvaes had no significant effect on the degeneration time of the thoracices and fore legs.2.The effects of D.helophoroides larvaes'density on the biochemical indexes of Z.atratus pupae.After inoculation of D.helophoroides larvae,the immune ability of Z.atratus pupae was enhanceded,and the nutrients such as sugar and protein in the host were gradually consumed with the increase of the pupal period.The activity of trehalase was negatively correlated with trehalose content,and the activity of alpha amylase regulated the change of carbohydrate content.As nutrients are eaten,protein is transformed into other substances and shows a state of continuous rising.By the 5th day,carbohydrates and alpha amylase are basically stable,it shows that the larvae of cashmere are mature and no longer feeding.The higher the density of the inoculated D.helophoroides larvae,the greater the nutritional requirements of the trehalose,glycogen and other carbohydrates of the Z.atratus pupae,and less demand for reducing sugar.3.The fitness of the growth and development of D.helophoroides.With the increase in the inoculation density of larvae,the cocooning rate,adult body length,body width,and body weight were significantly reduced,and the number of eclosion and theparasitic success rate were significantly increased.Comprehensive the factors about scarring rate,number of adult ecloses,individual body length,body width,and body weigh,it can be found that using a single nymph of Z.atratus,The optimum is the inoculated 3 D.helophoroides.The study provides a theoretical basis and technical support for improving the efficiency of artificial breeding of D.helophoroides by inoculating different density of D.helophoroides larvae to study the degenerative patterns of the fore legs thoracic,the nutrient utilization of the Z.atratus and their self growth and performance,finally,optimal inoculation density was selected.