Spatio-temporal changes in the gut microbiota of Popilla japonica (Coleoptera: Scarabaeidae)

The number of invasive insect species is increasing and once established, they have serious impacts on the environment and economy. Popillia japonica Newman (EPPO Code: POPIJA) (Coleoptera: Scarabaeidae), commonly known as the Japanese beetle, is a highly polyphagous beetle and an EPPO A2 pest (EPPO, 2006). Native to Japan and the far eastern Russian island of Kuril and has become an established pest in North America, the Azores and more recently in Europe. In 2014, was recorded for the first time on the European mainland when an outbreak was reported within the Ticino Valley Natural Park, Italy (EPPO, 2014). Insect-associated P. japonica bacteria have shown to play an important role in their host evolutionary success and adaptation to new environments and food resources. In this study, we investigated the microbiota associated with the three gut regions of different P. japonica developmental stages (i.e., larvae, pupae and adults) in order to address the following main biological questions: i) are the microbiotas associated with semaphoronts diverse? ii) are the bacterial communities associated with the three gut regions different? iii) Does the soil has an impact on shaping the bacterial community associated with different developmental stages of P. japonica (i.e. larvae, pupae and adults)?