Midgut Bacterial Communities of Vespa velutina Lepeletier (Hymenoptera: Vespidae)

Abstract

Vespa velutina nigrithorax and Vespa velutina auraria are two subspecies of Vespa velutina Lepeletier. V. velutina preys managed honey bees, other pollinators, and insects. However, the Vespa midgut microbiota of three forms, namely queens, workers, and males have not been reported, thus the objective of this study was to analyze the midgut bacterial diversity of the three forms of V. v. nigrithorax and V. v. auraria. Our results showed that Proteobacteria, Firmicutes, Bacteroidetes, Tenericutes, and Actinobacteria were the most abundant phyla, and Lactobacillus (17.21%) and Sphingomonas (11.39%) were the most abundant genera in the midgut of V. v. nigrithorax and V. v. auraria. We found that the midgut bacterial compositions of the V. velutina males were special, in terms of richness and diversity of bacterial communities, as well as the content of lactic acid bacteria. By comparing the gut bacterial compositions of Vespa from different regions (Japan, South Korea, Italy, and China), it was discovered that the gut bacterial compositions were very similar at the phylum and class level, and Gammaproteobacteria, Bacilli, and Alphaproteobacteria were the most abundant classes of bacteria and consistent in the genus Vespa. Besides, though Vespa from different regions had quite different gut bacterial communities at the genus level, Lactobacillus and other lactic acid bacteria were abundant and played important roles in protection and metabolism in V. velutina collected from different regions. This is the first report of midgut bacterial diversity of three forms queens, workers, and males of V. velutina. Our findings provide insight that Proteobacteria and Firmicutes (especially Lactobacillus and other lactic acid bacteria) are consistent and may play important roles in the genus Vespa. The understanding of the microbiome in the midgut of Vespa and the discovery of the vital bacteria would provide useful information to design pest biological control agents. Thus, the significance of this study is to provide a basis for the study of the relationship between gut microbiota and physiology and health of Vespa, as well as the control of Vespa.

Convivina is a specialised core gut symbiont of the invasive hornet Vespa velutina

“…Our study provided a comprehensive description of the cultivable bacterial community of the crop, midgut and hindgut compartments, as well as the ovaries of the invasive hornet V. velutina . While these results were obtained through the analysis of samples from a single nest of Asian hornets in Belgium, they were largely congruent with 16S rRNA amplicon sequencing data reported in Italy (Cini et al, 2020) and China (Zhang et al, 2022). The results obtained suggested that the Asian hornet bacterial community was dominated by Convivina , Fructobacillus , Lactococcus , Sphingomonas , Spiroplasma and Lactiplantibacillus .…”

“…We subsequently compared the results obtained with those of a 16S rRNA amplicon sequencing analysis of samples of the same nest to provide a more complete image of these bacterial communities, as both approaches have intrinsic biases and limitations (Duthoo et al, 2022; Hong et al, 2009; Lagier et al, 2012; O'Callaghan et al, 2021). Both cultivation‐independent and cultivation‐dependent approaches revealed a dominant occurrence of Bacillota and Pseudomonadota in the hornet's gut microbiota, which was consistent with results from other insect species (Yun et al, 2014), other hornet species (Suenami et al, 2019) and two recent studies of V. velutina (Cini et al, 2020; Zhang et al, 2022). While 16S rRNA gene amplicon sequencing revealed a different gut microbiota composition in each of the sample types (i.e., gut fractions and ovaries), each sample type displayed a similar richness and diversity (Figure S1).…”

“…Together, these data confirmed the presence of Lactococcus , Lactiplantibacillus , Fructobacillus , Sphingomonas and Convivina in the Italian study (Cini et al, 2020). Furthermore, Lactococcus , Lactiplantibacillus , Fructobacillus , Sphingomonas , and Spiroplasma were also reported in the midgut microbiome of V. velutina in the native region China (Zhang et al, 2022).…”

“…The adult stages harboured mainly bacilli and gammaproteobacteria which revealed little similarities to the bacterial community reported in the Korean hornets (Kim et al, 2018). Recently, the midgut bacterial communities in queens, workers, and males of two subspecies of V. velutina , V. velutina nigrithorax and V. velutina auraria , were characterised in China (Zhang et al, 2022). The midgut bacterial communities of the two subspecies were similar and dominated by Lactobacillus and Sphingomonas reads.…”

Gut bacterial diversity in Vespa velutina and implications for potential adaptation in South Korea

“…The gut bacterial communities in the five Vespa species predominantly consisted of Proteobacteria, accompanied by Firmicutes and Bacteroidetes, aligning with previous studies. 31 Inter-species differences in gut bacterial composition at the phylum level may bear ecological and physiological implications. We observed a higher relative abundance of Firmicutes in V. velutina and V. mandarinia than in V. analis, V. crabro, and V. ducalis.…”