Published online by Cambridge University Press: 19 September 2011
Population regulation is briefly explained, and the demographic parameter, r, is identified as a symptom of the dynamic balance between density-independent and density-dependent factors that respectively disturb or regulate population equilibria. Evidence for density-dependence in tsetse populations is reviewed under the general headings of direct and indirect observations. Direct evidence comes from predation experiments on both adults and puparia, and from experiments that measure the feeding success of tsetse on bait animals. Indirect evidence arises from detailed analyses of fly-round records. Natural density-dependence in tsetse populations, when it occurs, is shown to be considerable, and must always be allowed for in control programmes whose effectiveness it at least partly determines.