A polar insect's tale: observations on the life cycle of Parochlus steinenii, the only winged midge native to Antarctica

Antarctica and the sub-Antarctic islands are considered natural laboratories to study and understand the influence of environmental variable and patterns of variation therein on the biota, including the influences of climate change.  The Antarctic terrestrial fauna consists only of small invertebrates, with just two native species of holometabolous insects, Parochlus steinenii and Belgica antarctica, and two established non-native species, Eretmoptera murphyi and Trichocera maculipennis. Studies of the life history, phenology and stress tolerances of insects are critical to better understand adaptations to natural environmental stress and the ecological consequences of recent and ongoing climate change. In this context, we characterized the habitat preferences, life cycle and phenology of P. steinenii, the winged Antarctic midge, in a lake on King George Island, South Shetland Islands, maritime Antarctic.  Based on the data obtained, we hypothesize that P. steinenii has a multi-year life cycle that may span as much as four years. The species is very restricted in terms of its preferred microhabitat distribution, being highly abundant only at shallow depths close to the edge of the lakes in which it is found. A combination of further field and laboratory studies are now required to assess how the length of P. steinenii life cycle is influenced by the scale of temperature variation typically experienced in its natural habitat, and as predicted under different climate change scenarios, as well investigating the ability and timing of larval movement to take advantage of the conditions of specific microhabitats at different times of year.