Dynamics of symbiotic bacterial community in whole life stage of Harmonia axyridis (Coleoptera: Coccinellidae)

Abstract

IntroductionBacteria play critical roles in the reproduction, metabolism, physiology, and detoxification of their insect hosts. The ladybird beetle (Harmonia axyridis) harbors a myriad of endosymbiotic microbes. However, to date, little is known about how the microbial composition of H. axyridis varies throughout its life cycle.MethodsIn this study, 16S rRNA amplicon sequencing and quantitative PCR were employed to investigate the diversity and dynamics of bacterial symbionts across the egg, larval, pupae, and adults stages of H. axyridis.ResultsHigher bacterial community richness and diversity were observed in eggs, followed by those in adults and pupae. The community richness index differed significantly between second-instar larvae and other developmental stages. Proteobacteria, Firmicutes, and Actinobacteria were the dominant phyla. Staphylococcus, Enterobacter, Glutamicibacter, and Acinetobacter were the dominant bacteria genera; however, their relative abundances fluctuated across host developmental stages. Interestingly, the larval stage harbored high proportions of Firmicutes, whereas the adult microbial community largely consisted of Proteobacteria.DiscussionThis study is the first to determine the symbiotic bacterial composition across key life stages of H. axyridis. These outcomes can foster the development of environmental risk assessments and novel biological control strategies.

Geographical, seasonal, and growth-related dynamics of gut microbiota in a grapevine pest, Apolygus spinolae (Heteroptera: Miridae) Running title: Gut microbiota of a grapevine pest bug

“…In the rearing experiments on Adelphocoris suturatis, the proportion of Serratia increased when the insect was reared under carnivorous or omnivorous conditions [36], suggesting a metabolic function of this bacterial group when plant bugs feed on other insects. In addition, Serratia species are commonly detected in the gut of carnivorous and omnivorous insects, including mosquitoes (Aedes aegypti), fruit y (Drosophila), and ladybugs (Harmonia axyridis) [39][40][41]. Indeed, Serratia species are known to have urea metabolism and secrete highly active proteases and chitinases in insect bodies, suggesting that Serratia support host digestion [42].…”

Geographical, seasonal, and growth-related dynamics of gut microbiota in a grapevine pest, Apolygus spinolae (Heteroptera: Miridae)

“…In the rearing experiments on Adelphocoris suturatis, the proportion of Serratia increased when the insect was reared under carnivorous or omnivorous conditions [35], suggesting a metabolic function of this bacterial group when plant bugs feed on other insects. In addition, Serratia species are commonly detected in the gut of carnivorous and omnivorous insects, including mosquitoes (Aedes aegypti), Anopheles stephensi, fruit y (Drosophila), and ladybugs (Harmonia axyridis) [38][39][40][41]. Indeed, Serratia species are known to have urea metabolism and secrete highly active proteases and chitinases in insect bodies, suggesting that Serratia support host digestion [42].…”

Changes in the bacterial communities of Harmonia axyridis (Coleoptera: Coccinellidae) in response to long-term cold storage and progressive loss of egg viability in cold-stored beetles

“…The reproductive tracts of adult beetles from the LCS group and those from the control group were dissected according to the protocols outlined by Huang et al (2022) and Du et al (2022) . The adult surface was sterilized by immersion in 70% absolute ethanol for 3 min and rinsed three times in sterile phosphate-buffered saline.…”

“…Harmonia axyridis (Pallas) is an important natural enemy of aphids and is also recognized as a notorious invasive species ( Brown et al, 2011 ; Camacho-Cervantes et al, 2017 ). This ladybird beetle harbors a myriad of endosymbiotic microbes throughout life stages, with higher richness and diversity of bacterial community observed in eggs, followed by adults and pupae ( Du et al, 2022 ). In recent years, several studies have been conducted to reveal the response of H. axyridis ’s bacterial community to changes in food source or pesticide pressure.…”