The Chironomidae : Biology and ecology of non-biting midges : Springer : 9780412452604 : 041245260X : 31 Dec 1994 : The dipteran family Chironomidae is the most widely distributed and frequently the most abundant group of insects in freshwater, with rep­ resentatives in both terrestrial and marine environments. A very wide range of gradients of temperature, pH, oxygen concentration, salinity, current velocity, depth, productivity, altitude and latitude have been exploited, by at least some chironomid species, and in grossly polluted environments chironomids may be the only insects present. The ability to exist in such a wide range of conditions has been achieved largely by behavioural and physiological adaptations with relatively slight morphological changes. It has been estimated that the number of species world-wide may be as high as 15000. This high species diversity has been attributed to the antiquity of the family, relatively low vagility leading to isolation, and evolutionary pl