| Dastarcus helophoroides belongs to Coleoptera and is an important parasitic natural enemy of longophora pests.Feeding larvae and adults with alternative host and formula feed is a relatively perfect method for artificial population propagation at present.Food is an important source of intestinal microorganisms.Differences in intestinal microbial diversity,community composition and structure have not been reported at different development stages and after feeding different formulations.In this study,we studied the diversity,community structure and functional characteristics of intestinal microorganisms in D helophoroides at different developmental stages and feeding on different feeds,combined with amplified sequencing technology and metagenomic technology.The effects of different artificial diets on the growth,development and reproductive ability of the parents and offspring of D helophoroides were clarified.The relationship between intestinal microorganisms and life activities such as growth,development and reproduction was revealed after feeding different formulations.The main research results are as follows:1.The 16 S rDNA sequences of intestinal bacteria at 9 developmental stages and the ITS sequences of intestinal fungi at 4 developmental stages were obtained.The results of α-diversity of bacteria showed that the species diversity of intestinal bacteria was the highest,followed by adults and larvae.The β diversity showed that the intestinal community of larvae at L1 and L2 stages was quite different.Compared with pupae at P1 and P2 stages,the β diversity of P3 stage was close to that of adults at A1 and A2 stages.The relative abundance of Acinetobacter increased gradually in the pupal stage and decreased in the adult stage.The relative abundance of Enterococcus and Enterobacter increased gradually in the adult stage.KEEG analysis using metagenomic data showed that intestinal microbes play different functions at different developmental stages.The intestinal microbial genes of larvae L1 and adult A4 were mainly enriched in carbohydrate metabolic pathways,and pupa P2 and adult A1 were mainly enriched in amino acid metabolism.The body weight and body length of D.helophoroides adults fed on feed Ⅳ and feed Ⅵ were larger,the pre-oviposition period was shorter,the average number of eggs per female was more,the hatching rate and eclosion rate of the first generation of D.helophoroides were higher,and the D.helophoroides adults fed on feed I and feed Ⅱ were the opposite.On the whole,D.helophoroides fed on feed Ⅳ and feed Ⅵ supplemented with barley insect dry powder showed better growth and reproduction.2.To explore the intestinal microbial diversity and community structure of D.helophoroides fed on different diets on days 10,20 and 40.At the genus level,Lactococcus was the dominant genus in the intestinal tract of newly emerged D.helophoroides and adults fed on different diets.The relative abundance of Lactococcus in the intestinal tract of adults fed on diets Ⅳ and Ⅵ gradually increased with feeding time.The results of bacterial α-diversity analysis showed that the intestinal bacterial diversity and abundance of newly emerged adults were the highest,and feeding different feeds resulted in a decrease in bacterial diversity and abundance.Among them,the intestinal bacterial diversity of newly emerged D.helophoroides adults was the highest,followed by feed Ⅳ,and the diversity of feed Ⅵ was the lowest.The results of bacterial β-diversity analysis showed that the intestinal bacterial community structure of newly emerged D.helophoroides adults was quite different from that of D.helophoroides adults after feeding,but the intestinal bacterial community structure of D.helophoroides adults fed with different formulas was similar.3.The intestinal microbial diversity and community structure of D.helophoroides at different times after feeding on different diets changed compared with newly emerged adults,and the relative abundance of Lactococcus in the intestine of adults fed on diets Ⅳ and Ⅵ gradually increased with feeding time.The results of bacterial α-diversity analysis showed that the intestinal bacterial diversity and richness of newly emerged adults were the highest,and feeding different feeds resulted in a decrease in bacterial diversity and richness.The results of bacterial β-diversity analysis showed that the intestinal bacterial community structure of newly emerged D.helophoroides adults was quite different from that of D.helophoroides adults after feeding,but the intestinal bacterial community structure of D.helophoroides adults fed with different formulas was similar.4.The correlation between the relative abundance of intestinal bacteria and the growth,development and reproduction of the adult showed that the relative abundance of Lactobacillus was positively correlated with the preoviposition time,mortality,parasitism efficiency and cocoon formation rate,and negatively correlated with the body weight,body length and width of the parasite and single female oviposition.The relative abundance of Enterococcus was negatively correlated with the pre-oviposition period,mortality,parasitism efficiency and cocoon formation rate.The relative abundance of Bacillus was positively correlated with the preoviposition period and cocoon formation rate.In conclusion,the growth,development and reproduction of D helophoroides adults were positively correlated with the relative abundance of Lactobacillus and Bacillus,but negatively correlated with the relative abundance of Enterococcus.Based on the growth and development parameters of intestinal microorganisms and insects,the growth and development and reproduction of D.helophoroides fed on feed Ⅳ and feed Ⅵ supplemented with barley insect dry powder were better.From the perspective of growth and development of intestinal microorganisms and insects,this study laid the foundation for optimizing the formula of artificial feed,establishing the artificial feed suitable for long-term indoor breeding and realizing the large expansion of indoor population of D helophoroides. |
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