# Ontogenetic Analysis of Chelonus formosanus and Diversity of Its Internal Microbiota

## TL;DR

This study explores the development of a parasitic wasp and its internal bacteria, revealing how its microbiota changes across life stages.

## Contribution

The study provides the first detailed ontogenetic analysis and microbiota characterization of Chelonus formosanus.

## Key findings

- C. formosanus development spans 19.62 days with distinct microbiota at each stage.
- Enterobacter and Enterococcus dominate in larvae and pupae, while Pseudomonas dominates in female adults.
- Male adults are associated with Ralstonia and Achromobacter, with bacteria linked to metabolic pathways.

## Abstract

Chelonus formosanus (Sonan) is an egg–larval parasitoid wasp with enormous potential for the biological control of various Noctuidae pests. However, little is known about its ontogenetic development and the associated microbiota. In this study, we examined the ontogenetic characteristics of C. formosanus. We performed 16S bacterial amplicon sequencing at different developmental stages. This study elucidates the morphological and developmental dynamics of C. formosanus and reveals its microbiota abundance at different developmental stages. Our findings lay a solid foundation for understanding the complexity of core microorganisms colonizing C. formosanus.

Chelonus formosanus is a parasitic wasp capable of parasitizing various Noctuidae pests, including the highly invasive Spodoptera frugiperda, and it demonstrates strong pest control potential. Both egg and larval stages primarily occur within the host organism, and the total developmental time from egg to adult is approximately 19.62 days. To investigate the microbial communities at different stages, we performed 16S rDNA sequencing (V1–V9 region) using PacBio sequencing and identified 404 bacterial species belonging to 61 classes, 116 orders, 182 families, and 308 genera across larval, pupal, female, and male adult stages. Bacterial diversity and richness varied across the stages, with Enterobacter and Enterococcus dominating in larvae and pupae and Pseudomonas emerging as dominant in female adults. In contrast, male adults predominantly resided with Ralstonia and Achromobacter. The predicted functions of bacteria within C. formosanus at different developmental stages are predominantly marked by the high abundance of metabolic pathways. This study provides a comprehensive understanding of the morphology of C. formosanus and contributes to the practical control of host pests. Additionally, our findings preliminarily characterized the microbial community of various developmental stages, laying the groundwork for its functional study.