Effects of Temperature and Humidity on Ovipositional Biology and Egg Development of the Tropical Horse Tick, Dermacentor (Anocentor) Nitens

The ovipositional biology and egg development of the tropical horse tick, Dermacentor (Anocentor) nitens (Neumann), was observed at four temperatures (20, 25, 30, and 35 degrees C) and relative humidities (40, 61, 75, and 91% RH). Relative humidity had little effect on length of preoviposition and oviposition periods. With increased rearing temperatures, there was a decrease in both preoviposition and oviposition periods. Oviposition rate increased with temperature and was not affected by relative humidity. Instantaneous rates of oviposition were calculated for each temperature by fitting the data to the logistic growth function. High percentage egg hatch was observed in low saturation deficit environments, and decreased when saturation deficit was increased.