Geographical, seasonal, and growth-related dynamics of gut microbiota in a grapevine pest, Apolygus spinolae (Heteroptera: Miridae) Running title: Gut microbiota of a grapevine pest bug

A number of insects are associated with gut symbiotic microorganisms, wherein symbionts play pivotal metabolic roles such as nutrient supplementation, diet degradation, and pesticide detoxification. Despite the ecological and evolutionary importance of gut microbial communities in insects, their diversity and dynamics remain unclear in many insect species. The green plant bug Apolygus spinolae , a notorious grapevine pest in Japan, damages grape shoots and severely reduces grape berry yield and quality. The plant bug possesses a simple tubular gut housing ~ 10 ⁴ bacteria. Here we investigated geographic, seasonal, and growth-related dynamics of gut microbiota by high-throughput sequencing in 82 individuals (11 nymphs and 71 adults) from five locations in Hokkaido, Japan. In plant bugs, gut microbiota changed dynamically depending on geographic region, season, and developmental stage, in which particularly Serratia and Caballeronia were abundantly detected. Among the gut bacteria, Serratia was consistently and abundantly detected, but significantly affected by seasonal changes. In addition, Caballeronia , known as a specific symbiont of some stinkbug species, was abundantly detected, especially in insects collected in late summer. The increase in Caballeronia was negatively correlated with Serratia , strongly suggesting an antagonistic interaction between gut bacterial members in A. spinolae .