Abstract
Halyomorpha halys (St & aring;l) (Hemiptera: Pentatomidae) is an invasive pest for agricultural production. It is associated with the primary symbiont "Candidatus Pantoea carbekii", which is essential for the host's fitness. In a laboratory rearing, a significant loss of fitness was observed, but the reasons remained unknown. Since bacterial symbionts are known to have an important impact on the fitness of their hosts, we investigated the gut microbiota of laboratory-reared H. halys individuals based on 16S rRNA gene metabarcoding. We analyzed individuals from different generations and compared their microbiota to field-collected individuals. The results showed significant differences between natural and laboratory-reared insects. Especially, the primary symbiont Pantoea, which was the most abundant taxon in the field, was lost and replaced by unclassified Enterobacteriaceae and Yersiniaceae. Our results indicate that changes in the composition of the microbial community of the laboratory-reared H. halys had a significant negative influence on the fitness in the laboratory and highlight the impact of changing conditions to the microbial community of insects with consequences on their fitness.