This study describes the ecology and distribution of the only two native Antarctic insects, the chironomid species Parochlus steinenii and Belgica antarctica, both found on Byers Peninsula (Livingston Island, South Shetland Islands). Parochlus steinenii inhabits lakes of the central plateau of Byers Peninsula associated with aquatic mosses on the bottom of lakes and in some streams of the South Beach area. Some streams have stable populations which are able to complete their life cycle while other streams have temporary, unstable populations. Belgica antarctica also inhabits streams running through mosses located in the South Beach area. Our data indicate that this species has a limited dispersal capability which is positively light activated for both adults and pupae. Both Antarctic midge species coexists on Byers Peninsula and share some stretches of streams. Isotopic studies show a non-selective feeding regime for both species with mixed carbon sources associated with both biofilm/microbial mats and mosses.
