Transcriptome And Cost Analysis Oiarma Chinensis Reared On Insect-free Artificial Diet

Arma chinensis is predaceous insect species that can effectively suppress agricultural and forestpests of Lepidoptera, Coleoptera, Hymenoptera and Hemiptera. This study developed a zoophytogenous,insect-free artificial diet, and sequcenced the transcriptome of A. chinensis reared on pupae of Chineseoak silk moth and artificial diet. Moreover, effect of food on development and cost analysis forcontinuous rearing of A. chinensis for12generations on different food was studied.An artificial diet comprised of pig liver, chicken egg and tuna fish but devoid of insect componentswas developed for the predator A. chinensis for six generations. Weight, body length of eggs and adults,fecundity and egg viability were lower for diet-fed A. chinensis compared to A. chinensis reared onpupae of the factitious host, Chinese oak silk moth Antheraea pernyi. Developmental time from2ndinstar to adult and the preovipositional period were significantly longer for diet-fed A. chinensis.Cannibalism was also higher with diet-fed A. chinensis. Nymphal weight, body length, longevity ofadult, survival from2nd instar to adult, and fertility increased, but the sex ratio (:) decreased, withrearing consecutive generations on the diet. These changes may indicate that the predators experiencesome degree of adaptation to, or selection for, the diet after several consecutive generations. There wereno changes in developmental time of egg and1st instar, or survival from1st to2nd instar withsuccessive generations reared on the artificial diet. Females under all treatments were heavier than themales, and the males lived longer than females.In this study, I sequenced and characterized the transcriptome in artificial diet-fed and Chinese oaksilk moth pupae-fed A. chinensis. Among13,872differentially expressed genes with significantlydifferential expression levels, more genes (10,261) were up-regulated in diet-fed insects. Additionally,many metabolic pathways related to nutrition were up-regulated in diet-fed A. chinensis, in some casesindicating excess quantities of specific nutrients in the diet. This study showed that a nutrigenomicapproach holds promise for deciphering the impact of dietary changes in insects and for improving dietformulations. The changes in gene expression caused by dietary changes were correlated tophysiological differences observed in diet-fed and pupae-fed A. chinensis. Several differentiallyexpressed genes related to these different physiological properties were found, such as heat shockprotein90, seminal fluid protein, juvenile hormone esterase, Cu, Zn-superoxide dismutase, antennalesterase CXE19, and odorant binding protein15. It is worth noting that transcriptome analyses enableddetermination of effects on male performance (e.g., expression of seminal fluid proteins), which is noteasily attained via life history analyses. Also of importance, I found some metabolic pathways related tonutrition and differentially expressed nutrient-controlled genes, from which a more informativefeedback for diet formulation was obtained and the artificial diet could be more efficiently optimized. Inaddition, a number of SNPs and microsatellite markers were predicted, which upon validation couldfacilitate the identification of polymorphisms within A. chinensis populations. The impact of this insect-free artificial diet on the biological characteristics was examined over12consecutive generations for A. chinensis. This study showed that when fed an insect-free artificial dietduring both the nymphal and adult stages, developmental times were prolonged, and the netreproductive rates (R0) and the intrinsic rates of increase (rm) were significantly lower than when fedpupae of Chinese oak silk moth at both nymphal and adult stages. Moreover, the cost to rear A.chinensis on the artificial diet approached1.7times the cost of rearing A. chinensis on secondary prey.Optimizing the artificial diet formula according to the results of transcriptome will potentially save thecost of the zoophytogenous artificial diet for rearing this beneficial pentatomid.