Factors regulating activity of adult Rhipicephalus appendiculatus ticks were investigated. Observations were made on ticks treated to 100% hydration, 85% hydration and 65% hydration during the hot dry, hot wet (rainy) and cool dry seasons. Two-months old and 6-months old ticks of each sex were released in two different habitats in 25 × 25 cm enclosures.
Comparisons were made between the number of ticks in each group seen on the upper part of the vegetation at intervals of 2 hr during daylight hours only. Although temperature changes seemed to be the cue to tick activity, the immediate activity shown by the 100% hydrated ticks and the delayed activity of the dehydrated groups after release, suggested that only fully hydrated ticks were responsive to temperature changes.
The most commonly recorded temperatures were within the range at which tick activity appeared to be at its maximum. During the daily temperature cycle, reduced activity was observed when the temperature was outside these limits. Activity increased again as soon as the temperature returned to the optimum range.