A dipteran from south of the Antarctic Circle: Belgica antarctica (Chironomidae) with a description of its larva

Abstract

Belgica antarctica Jacobs is recorded for the first time from two localities south of the Antarctic circle: Orford Cliff (66"55'S) on the Continental mainland and the Refuge Islands (68"21'S). The larva is described, and measurements of head capsule lengths indicate four instars. The larvae south of the Antarctic circle appear to be slightly smaller than those from within the main distributional range. Bcfgica antarcfica is certainly the earth's southernmost free-living holometabolous insect, but the flea Glaciopyffus antarcficus has been recorded 14 minutes of latitude farther south than the southernmost records of B. anfurctica.

Moist habitats are essential for adults of the Antarctic midge, Belgica antarctica (Diptera: Chironomidae), to avoid dehydration

“…Only two other dipterans, also midges, exist in sub-Antarctic regions: Parochlus steinenii is limited to Tierra del Fuego in South America along with several islands north of Antarctica and Eretmoptera murphyi has recently been introduced accidentally to a northern region of the Antarctic Peninsula (Convey & Block, 1996). The life cycle of B. antarctica has been thoroughly detailed and is highlighted by a two-year period of development (Usher & Edwards, 1984), similar to that observed for both P. steinenii and E. murphyi (Convey & Block, 1996). Wingless adults emerge during the summer after a brief pupal period and mate within aggregations.…”

“…Exact ages of the adults were not known, but considering their short life span and highly synchronized emergence (Sugg et al, 1983;Usher & Edwards, 1984), they were likely to be similar in age. Once collected, the adults were held at 98% RH, 4°C and 20L : 4D for 1 d to eliminate the effects of digestion, secretion and defecation on mass changes (Wharton, 1985).…”

The protective effect of rapid cold-hardening develops more quickly in frozen versus supercooled larvae of the Antarctic midge, Belgica antarctica

“…Endemic to the Antarctic Peninsula, the terrestrial midge Belgica antarctica Jacobs (Diptera: Chironomidae) is the southernmost freeliving species of insect (Sugg et al, 1983;Usher and Edwards, 1984). During its 2-year life cycle, overwintering larvae are encased in a matrix of substrate and ice for up to 7-8months each year.…”

Sobre el carácter alas en Belgica Antartica (Diptera: Chironomidae) registrado erróneamente en la literatura

“…Fue descrito brevemente por Jacobs (1900), sobre la base de una captura de 50 adultos (Usher & Edwards 1984) procedente del estrecho de Gerlache, Antártida chilena. Stuardo (1946), la señala como una de "las especies más australes de nuestra fauna dipterológica".…”