The microbiome of an invasive Antarctic insect, Eretmoptera murphyi (Diptera: Chironomidae), and its potential role in nutrient cycling

Abstract Eretmoptera murphyi is a flightless chironomid midge endemic to South Georgia in the sub-Antarctic. In the 1960s it was accidentally introduced to Signy Island (in the maritime Antarctic), where it is now considered an invasive species. This study set out to assess the archaeal and bacterial microbiome of E. murphyi to enhance understanding of the ecological impacts of this non-native species. Previous work has revealed that the detritivorous larvae of E. murphyi can increase soil nitrogen levels by up to five times compared with similar uncolonized substrates, although the mechanisms involved are not known. As nutrient availability in Antarctic terrestrial habitats is an important limitation to biodiversity and the development of communities, any significant change could impact native microarthropod and plant communities as well as open new pathways for future non-native species establishment. Dominant archaea and bacteria were: Crenarchaeota, Actinobacteriota, Chloroflexi, Proteobacteria and Planctomycetota, many of which have known roles in nutrient cycling. The microbiome of E. murphyi appears to be more diverse than those of the few Antarctic invertebrates studied to date. Further work is required to confirm which microorganisms are true endosymbionts and their specific roles in nutrient cycling in polar terrestrial ecosystems.