CATASTROPHIC CHANGE IN BUTTERFLY POPULATION

A scheme for monitoring and conserving the species of butterflies at 4-5 sites in Kanpur has been described with indices of abundance in different seasons. There are marked differences between the species in the scale of seasonal fluctuations. The species show correlation between successive index values e.g. the summer generation index of Pieris brassicae is highly correlated with the spring generation. The adverse climate is believed to have severely depressed the population of many species in cold winter. The data do not indicate any general fall in butterfly numbers over the period at the sites in the acheme. The sites are representative only for a number of species not for a whole.