Chironomidae (Diptera) of Australia

Abstract

Data on the Chironomidae of Australia are reviewed and related to four broad ecological water types: permanent lentic, ephemeral lentic, lotic, and marine. The information is discussed in terms of three major elements in the composition of the chironomid fauna of Australia: common cosmopolitan genera, endemic genera, and genera with a distribution on southern land masses. The contribution highlights the following six points. (a) Common cosmopolitan genera utilizing lentic waters are reasonably well known; however, information on lotic-water genera is minimal. With ever-increasing impoundment of waters by man, surveys need to be initiated quickly or much basic data on ecology and distribution of lotic-water genera will be lost. (b) Apart from the endemic genera Paraborniella and Allotrissocladlus, which survive in a partly hydrated state in dried-out pools, utilization of ephemeral waters is by opportunistic permanent-water genera, which show no adaptations to resist desiccation and which seek refuge in permanent waters during dry periods. (c) Chironomid populations in streams in the Darling Range, Western Australia, show major temporal changes in composition associated with marked seasonal winter rainfall. It is suggested that adaptation to seasonal winter rain is a marked feature of fauna in southwestern Australia. (d) The Allotrissocladius species complex provides a clear example of a proposed model for in situ speciation of the aquatic fauna in south-western Australia. (e) Among the genera distributed on southern land masses, Archaeochlus and Aphroteniella provide evidence of Gondwanaland connections with South Africa and South America, respectively. (f) Chironomids are the most abundant faunal element in lentic and lotic waters; however, because of the lack of suitable identification for life-history stages, the importance of the family in aquatic ecological studies is underestimated. The need to complete taxonomic studies is stressed.