Eating eggplants as a cucurbit feeder: Dietary shifts affect the gut microbiome of the melon fly Zeugodacus cucurbitae (Diptera, Tephritidae)

All raw sequence read data are available from the European Nucleotide Archive under the accession number PRJEB49793: https://www.ebi.ac.uk/ena/browser/view/PRJEB49793. Sample data set, sample metadata, and codes for analysis are available on GitHub: https://github.com/wouterhendrycks/tephritid_microbiome_host_switch_project and in Zenodo: https://doi.org/10.5281/zenodo.6810766.Supporting Information table (Differential abundance analysis of bacterial genera between larval microbiomes from larvae between different host plants and between different sites using ALDEx2) is available in the Zenodo repository at https://doi.org/10.5281/zenodo.6811204).; International audience; Graphical Abstract:We investigated how the gut microbiome composition changes in a cucurbit-feeding fly Zeugodacus cucurbitae when it feeds on atypical solanaceous hosts instead of typical cucurbit hosts. Wild parental (F0) adults and semiwild first filial (F1) larvae of Z. cucurbitae collected from two locations in Réunion Island showed heterogeneous microbiome responses across host plants. This study shows how local processes and host plants can strongly affect the composition of the insect microbiome and the importance of using adequately sampled populations. Figure: https://onlinelibrary.wiley.com/cms/asset/10ec8f92-c6b0-4f27-aaf0-0ed246f23aa9/mbo31307-gra-0001-m.jpgAbstract: While contemporary changes in feeding preferences have been documented in phytophagous insects, the mechanisms behind these processes remain to be fully clarified. In this context, the insect gut microbiome plays a central role in adaptation to novel host plants. The cucurbit frugivorous fruit fly Zeugodacus cucurbitae (Diptera, Tephritidae) has occasionally been reported on "unconventional" host plants from different families, including Solanaceae. In this study, we focus on wild parental (F-0) adults and semiwild first filial (F-1) larvae of Z. cucurbitae from multiple sites in La Reunion and explore how the gut microbiome composition changes when this fly is feeding on a noncucurbit host (Solanum melongena). Our analyses show nonobvious gut microbiome responses following the F-0-F-1 host shift and the importance of not just diet but also local effects, which heavily affected the diversity and composition of microbiomes. We identified the main bacterial genera responsible for differences between treatments. These data further stress the importance of a careful approach when drawing general conclusions based on laboratory populations or inadequately replicated field samples.