Gut microbiota metabolic potential correlates with body size between mulberry‐feeding lepidopteran pest species

Abstract

BACKGROUND Many insect pests rely on microbial symbionts to obtain nutrients or for defence, thereby allowing them to exploit novel food sources and degrade environmental xenobiotics, including pesticides. Although Lepidoptera is one of the most diverse insect taxa and includes important agricultural pests, lepidopteran microbiotas, particularly functional traits, have not been studied widely. Here, we provide a comprehensive characterization of the gut microbiota across multiple mulberry‐feeding lepidopteran species, resolving both community structure and metabolic potential. RESULTS Our results indicate abundant bacteria inside the gut of larval Lepidoptera. However, even though they were fed the same diet, the structures of the bacterial communities differed in four major mulberry pest species, suggesting host‐specific effects on microbial associations. Community‐level metabolic reconstructions further showed that although taxonomic composition varied greatly, carbohydrate and amino acid metabolism and membrane transporter were key functional capabilities of the gut bacteria in all samples, which may play basic roles in the larval gut. In addition, principal coordinate analysis (PCoA) of gut bacterial‐predicted gene ontologies revealed specialized features of the microbiota associated with these mulberry pests, which were divided into two distinct clusters (macrolepidopterans and microlepidopterans). This pattern became even more prominent when further Lepidoptera species were involved. CONCLUSIONS A suite of gut microbiota metabolic functions significantly correlated with larval size; the metabolism of terpenoids and polyketides, xenobiotics biodegradation and metabolism were specifically enriched in large species, while small larvae had enhanced nucleotide metabolism. Our report paves the way for uncovering the correlation between host phenotype and microbial symbiosis in this notorious insect pest group. © 2019 Society of Chemical Industry

Comparison of Gut Bacterial Communities of Grapholita molesta (Lepidoptera: Tortricidae) Reared on Different Host Plants

“…However, in the two treatment groups that fed on an artificial feed and plums, the following four phyla were dominant: Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota. Many studies have reported that Proteobacteria and Firmicutes are the dominant bacterial phyla in insect gut bacterial communities, especially Lepidoptera [34,[41][42][43][44]. They play a key role in carbohydrate metabolism, amino acid metabolism, and membrane transport pathways of the host [20,45,46].…”

Of Cockroaches and Symbionts: Recent Advances in the Characterization of the Relationship between Blattella germanica and Its Dual Symbiotic System

“…Regarding the extracellular gut microbiota, complex microbial communities inhabiting the digestive tracts have also been studied in a wide variety of insects, such as termites [17][18][19], cockroaches, crickets, beetles [20,21], lepidopterans [22,23], hymenopterans [24] and Drosophila [25]. These studies revealed that the nature, diversity, complexity and functions of the gut microbiota are highly variable across the different groups of class Insecta [7].…”

Midgut bacterial diversity of a leaf-mining beetle, Dactylispa xanthospila (Gestro) (Coleoptera: Chrysomelidae: Cassidinae)

“…Insects comprise numerous species, have various habitats and use diverse foods ( Basset et al 2012 , Shi et al 2010 ) and thus have correspondingly evolved diverse gut characteristics and microbiota ( Engel and Moran 2013 ). Some gut microorganisms improve the host’s nutritional, digestive and reproductive fitness and even pathogen defence ( Chen et al 2020 , Douglas 2015 , Engel and Moran 2013 , Liu et al 2020 , Wang et al 2020 ). Gut microbial composition of insects are largely affected by host feeding habits ( Colman et al 2012 , Wang et al 2020 , Liu et al 2020 , Yun et al 2014 ).…”

“…Gut microbial composition of insects are largely affected by host feeding habits ( Colman et al 2012 , Wang et al 2020 , Liu et al 2020 , Yun et al 2014 ). Moreover, gut microbiota can vary when insects feed on different plant parts of the same host species ( Chen et al 2020 ).…”