The prehatch period and larval survival of Boophilus decoloratus (Koch, 1844) (Acarina: Ixodidae) under natural conditions in the Transvaal, South Africa

Abstract

Studies were made on the duration of the prehatch period of Boophilus decoloratus and on the subsequent survival and viability of larvae under natural conditions. The length of the prehatch and larval survival periods was found to be inversely dependent on increased temperature. A high initial temperature at the time of female drop decreased the prehatch period further, resulting in synchronous hatching of eggs laid at different times. Oviposition occurred but no eggs hatched during mid-winter months with mean temperatures below 10°C. Eggs laid after mid-winter hatched because of the higher temperatures during subsequent months. Diapause occurs at the egg stage in areas with mean winter temperatures below 10°C. Larvae survived for 10 - 35 weeks during periods of high and low seasonal temperatures respectively. Larval viability decreased concomitantly with larval survival. The results suggest that pasture spelling alone would be impractical as a control measure for this tick species.