Physiological Response Of The Larvae To Starvation In Hermetia Illucens

The black soldier fly(BSF),Hermetia illucens,is an important insect resource.Its application in organic waste treatment has attracted wide attention.BSF larvae are always supplied food for several times in production to avoid food mildew or caking due to their long developmental duration.Otherwise,the larvae will starve.In addition,the larvae will also starve when they are not supplied food during long transportation.At present,the effect of starvation on BSF has not been reported.Therefore,biological and physiological effects of starvation on BSF larvae were mainly studied in this research.The results can provide basic information for its industrialization development.The main results are as follows:1.Starvation resistance of larvaeNormal fed larvae had the highest daily growth rate at 4-5 d,maximum weight increase at 7-9 d,and maximum weight at 13 d.Head morphology of the prepupae can be used as the main identification character.Median lethal time(LT50)was significantly and positively correlated with age and weight of larvae under starving.2.Biological characters of larvae fed after starvingThe 7 day-old larvae were fed after different starvation time.Prepupae were observed at the 7th day after refeeding in all the treatments.The time of the cumulative quantity about half larvae reached the prepupal stage was 1 day later in the treatment of 30 d starvation than other treatments.Prepupal rate was significantly higher in starvation-experienced larvae than that of the control.Prepupal weight was increased if larvae were starved for 10-30 d.Prepupal weight from the larvae starved for 15 d was the heaviest among all the treatments.Starvationexperience had little effect on oviposition amount of the adults.Hatching rate of the eggs were significantly reduced if the adults were from the larvae starved for 30 d and 40 d.3.Physiological effects of starvation on larvaeAt early stage and the later stage the starved larvae mainly consumed fat and protein,respectively.The similar change of peroxidase activity and total antioxidant capacity was observed in starved larvae.Superoxide dismutase activity was sharply declined from 5 d starvation.Hydrogen peroxide enzyme activity changed rapidly.4.Digital gene expression of starved larvae and consequent prepupaeA total of 38,782 genes were obtained.As compared to the control,differently expressed genes identified from the larvae starved for 5,15,and 30 d were 6879,975,and 10190,respectively.Differently expressed genes identified from consequent prepupae were 3271,3178,and 1534,respectively.In conclusion,this study confirmed that the larvae of different sizes had strong starvation resistance,and the output of prepupae was significantly increased after refeeding of starved larvae.This result can provide the method for the production of BSF.The determination of the changes about physiological substances during starving in the larvae and the determination of the gene expression profiling can provide data support for further study on the starvation resistance of BSF.