The bacterial community associated with adult vine weevil (Otiorhynchus sulcatus) in UK populations growing on strawberry is dominated by Candidatus Nardonella

Abstract

Otiorhynchus sulcatus (Fabricius) (Coleoptera: Curculionidae), commonly known as black vine weevil or simply vine weevil, is an important pest of soft fruit and ornamental crops. This species is endemic to temperate areas of Europe but has spread to many other areas over the last century, including North America and Australasia. The ability of vine weevils to adapt to such different environments is difficult to reconcile with the parthenogenetic reproduction strategy, which is likely to underpin a low genetic diversity. It is therefore tempting to hypothesize that weevil adaptation to different environments is mediated, at least partly, by the microbial communities inhabiting these insects. As a first step towards testing this hypothesis we characterized the composition of the bacterial microbiota in weevils from populations feeding on strawberry plants across four geographically separate locations in the UK. We performed 16S rRNA gene Illumina amplicon sequencing, generating 2 882 853 high‐quality reads. Ecological indices, namely Chao1 and Shannon, revealed that the populations used for this study harboured a low diversity and an uneven bacterial microbiota. Furthermore, β‐diversity analysis failed to identify a clear association between microbiota composition and location. Notably, a single operational taxonomic unit phylogenetically related to Candidatus Nardonella accounted for 81% of the total sequencing reads for all tested insects. Our results indicate that vine weevil bacterial microbiota resembles that of other insects as it has low diversity and it is dominated by few taxa. A prediction of this observation is that location per se may not be a determinant of the microbiota inhabiting weevil populations. Rather, other or additional selective pressures, such as the plant species used as a food source, ultimately shape the weevil bacterial microbiota. Our results will serve as a reference framework to investigate other or additional hypotheses aimed at elucidating vine weevil adaptation to its environment.

A fitness cost resulting from Hamiltonella defensa infection is associated with altered probing and feeding behaviour in Rhopalosiphum padi

“…Infection with facultative (non-essential) endosymbiotic bacteria is widespread within herbivorous arthropod populations, including aphids (Luna et al, 2018), whiteflies (Ghosh et al, 2018), psyllids (Hansen et al, 2012), mites (Zhu et al, 2018) and weevils (Morera-Margarit et al, 2019). Many of these herbivorous arthropods are important agricultural and horticultural pests, and, therefore, understanding the effects of symbiont infection on arthropod fitness, arthropod pest status and the interactions between multiple trophic levels is a dynamic area of research (Oliver et al, 2014;McLean et al, 2016;Zytynska and Meyer, 2019).…”

Could bacterial associations determine the success of weevil species?

“…Various studies have revealed the presence of a core microbiota shared by populations of the same weevil species found at separate geographic locations. This is the case for the gut microbiota of the bark beetles Dendroctonus valens (Le Conte) and Dendroctonus mexicanus (Hopkins) in Mexico (Hernández‐García et al, 2018) and for the whole body microbiota of the vine weevil in the United Kingdom (Morera‐Margarit et al, 2019). For example, mountain pine beetles collected at separate locations shared a similar bacterial community.…”

Geographic origin may not influence vine weevil Otiorhynchus sulcatus (Fabricius) susceptibility to the entomopathogenic fungus Metarhizium brunneum (Petch)

“…To identify population diversity at a microbial level, Morera-Margarit et al (2019) characterised the bacterial community of vine weevils from various locations. The populations tested harboured very similar bacterial community compositions.…”

“…However, the application of the newly developed bioinformatic pipeline QIIME2 could reveal greater between population variation in future investigations. Morera-Margarit et al (2019) used QIIME for the analysis of the vine weevil microbiota. This is an open-source bioinformatics pipeline for performing microbiome analysis from raw DNA sequencing.…”