Comparative study of the gut microbial community structure of and (Lepidoptera).

BACKGROUND

, the fall armyworm is a destructive invasive pest, and the tobacco cutworm, is a native species closely related to . The gut microbiota plays a vital role in insect growth, development, metabolism and immune system. Research on the competition between invasive species and closely related native species has focused on differences in the adaptability of insects to the environment. Little is known about gut symbiotic microbe composition and its role in influencing competitive differences between these two insects.

METHODS

We used a culture-independent approach targeting the 16S rRNA gene of gut bacteria of 5th instar larvae of and . Larvae were reared continuously on maize leaves for five generations. We analyzed the composition, abundance, diversity, and metabolic function of gut microbiomes of and larvae.

RESULTS

Firmicutes, Proteobacteria, and Bacteroidetes were the dominant bacterial phyla in both species. , , , , and were the genera with the highest abundance in . , , , , and had the highest abundance in . According to -diversity analysis, the gut bacterial diversity of was significantly higher than that of . KEGG analysis showed 15 significant differences in metabolic pathways between and gut bacteria, including transcription, cell growth and death, excretory system and circulatory system pathways.

CONCLUSION

In the same habitat, the larvae of and showed significant differences in gut bacterial diversity and community composition. Regarding the composition and function of gut bacteria, the invasive species may have a competitive advantage over . This study provides a foundation for developing control strategies for and .