Frequencies of developmental morphs of Chaoborus americanus in four fishless bog lakes

Samples of fourth instar larvae of the phantom midge Chaoborus americanus from four fishless lakes were analyzed for frequencies of different developmental morphs. The percentages of fast-developing morphs found were 92.9, 98.3, 19.6 and 39.2. These values did not correlate with lake temperature regimes. Lake temperature was correlated with the rate of pupation of fast-developing morphs.