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.