Feeding Spodoptera exigua larvae with gut-derived Escherichia sp. increases larval juvenile hormone levels inhibiting cannibalism

作者：Xing-Xing Du, Sheng‐Kai Cao, Hua-Yan Xiao, Chang-Jin Yang, Aiping Zeng, Gong Chen, Huan Yu · 发表于：Communications Biology · 年份：2023 · DOI：10.1038/s42003-023-05466-x · 被引用次数：9 · 研究领域：Insect symbiosis and bacterial influences、Mosquito-borne diseases and control、Insect and Arachnid Ecology and Behavior

Abstract Feed quality influences insect cannibalistic behavior and gut microbial communities. In the present study, Spodoptera exigua larvae were fed six different artificial diets, and one of these diets (Diet 3) delayed larval cannibalistic behavior and reduced the cannibalism ratio after ingestion. Diet 3-fed larvae had the highest gut bacterial load (1.396 ± 0.556 × 10 14 bacteria/mg gut), whereas Diet 2-fed larvae had the lowest gut bacterial load (3.076 ± 1.368 × 10 12 bacteria/mg gut). The gut bacterial composition and diversity of different diet-fed S. exigua larvae varied according to the 16S rRNA gene sequence analysis. Enterobacteriaceae was specific to the Diet 3-fed larval gut. Fifteen culturable bacterial isolates were obtained from the midgut of Diet 3-fed larvae. Of these, ten belonged to Escherichia sp . After administration with Diet 1- or 2-fed S. exigua larvae, two bacterial isolates ( SePC-12 and -37 ) delayed cannibalistic behavior in both tested larval groups. Diet 2-fed larvae had the lowest Juvenile hormone (JH) concentration and were more aggressive against intraspecific predation. However, SePC-12 loading increased the JH hormone levels in Diet 2-fed larvae and inhibited their cannibalism. Bacteria in the larval midgut are involved in the stabilization of JH levels, thereby regulating host larval cannibalistic behavior.