The Bacterial Communities In Two Lady Beetle Species

Microorganisms are not only found in the environment,but also in various tissues and organs of animals including gut.The relationship between gut microbes and host insects is mainly nutrient exchange,defense,detoxification,etc..Microbes also affect the survival and evolution of host insects.Gut microbiota can seriously influence the health status and growth of the host.Previously many studies have been carried on the changes of gut microbial composition,but only a very small number of them are based on individuals.What we can find are some research on Drosophila.For other insects,especially predatory ladybeetles,the investigation of the diversity and structure of the gut microbial flora in individual insects is rarely reported.In this study,we used two predatory ladybeetles species,Harmonia axyridis(Pallas)and Coccinella septempunctata Linnaeus.They are natural enemy insects in the ecosystem and play a key role in controlling major crop pests such as aphids,whiteflies and plant hoppers.The 16 S rDNA high-throughput sequencing method was used to classify and identify the gut microbial flora of these insects collected in the field,and to explore the diversity characteristics of the gut symbiotic bacteria.Here are three main findings:1.The bacterial communities between ladybeetles and their habitats(such as aphids and plants)are significantly different.Some gut microorganisms are not present or extremely low in the environment.This indicates that there are commensal bacteria communities independent of environmental factors in the ladybeetle.At the same time,the species and quantity of gut symbiotic bacteria are non-uniform so there are species-specific dominant bacteria(for instance,the abundance of Proteobacteria in C.septempunctata Linnaeus ladybeetle is higher than H.axyridis(Pallas)ladybeetle).2.H.axyridis(Pallas)ladybeetle and C.septempunctata Linnaeus share the same microbial flora(such as Phytophrenia Phyllobacterium,Stenotrophomonas,Ralstonia,Vibrio,sphingosine,Sphingomonas,Candidatus_Bacilloplasma,Lactobacillus,unidentified_Ruminococcaceae and Buchnera),and they also have their own microbial flora respectively(such as Subdoligranulum,Fusobacterium Etc.in H.axyridis(Pallas),and Enterococcus,Streptococcus,etc.in C.septempunctata Linnaeus).3.The composition of gut microbial flora in the same species affected by the time and place of collection so there was a certain randomness in the composition of gut microbial flora.Overall,the composition of the gut microbial flora in predatory ladybeetles is determined by both species-specific certainty factors and non-deterministic(random)factors.