The collapse of Glossina tachinoides populations, within a 27-month period of weekly sampling by means of unbaited biconical traps, in two peridomestic agroecosystems is described. Consistent removal of parous flies through trapping and low recruitment of young flies into the population, were largely responsible for unabated decline in the apparent density of both G. tachinoides populations. Reduction in the size of the resident pig population to below five pigs/week/agroecosystem triggered the collapse of both tsetse populations. Some ecological implications of these findings and their possible application in tsetse control are discussed.