The seasonal activity of Rhipicephalus appendiculatus Neumann 1901 (Acarina: Ixodidae) in the highveld of Zimbabwe Rhodesia.

Rhipicephalus appendiculatus passes through one generation per annum in the highveld of Zimbabwe, Rhodesia and shows a well-defined pattern of seasonal activity. Peak adult activity occurs in the rainy season, whereas peak larval and nymphal activity occurs in the dry season. Adult activity is regulated by the combined influences of temperature, humidity, and day length. Climatic factors have little or no direct influence on the activity of larvae and nymphs. The occurrence of the larval and nymphal activity peaks is determined by the timing of the adult activity peak and the duration of the preceeding developmental periods, which are temperature dependent. In the early rainy season, unfed adults climb to the tips of the grass and enter a period of quiescence prior to becoming active.