PARENT SESSION
Poster Session #62: Parasite-Host Interactions.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Effects of air temperature and relative humidity on diurnal questing of Rhipicephalus pulchellus.

Allan, Brian^*,1, ¹ Mpala Research Centre, Nanyuki, Kenya

ABSTRACT- Tick-borne diseases affecting livestock production cause global losses of US$13.9-18.7 billion annually. The use of acaricides to reduce tick burdens on cattle is the only control method presently available, and is costly and only partially effective. However, studies of tick questing behavior in North America and Africa demonstrate diurnal variation in questing activity in accord with abiotic conditions, suggesting that alternate herding strategies could reduce dependence on acaricides. I test the hypothesis that the abundance of questing Rhipicephalus pulchellus is lowest at mid-day, due to diurnal changes in temperature and relative humidity. I sampled abundances of all life stages of questing ticks by performing hourly walking surveys, 100m in length, during daylight hours, in a location of high tick abundance in central Kenya. Larval and nymphal R. pulchellus demonstrated a significant U-shaped pattern, with higher abundances of juvenile ticks early and late in the day (larvae R² = 0.43, nymphs R² = 0.53). Adult ticks showed a similar but non-significant trend. Because cattle managers in this region move animals into fields early and late in the day, the periods of highest tick activity correspond to the periods of greatest exposure by cattle. These results suggest that changing the timing of livestock movements could reduce disease incidence and dependence on acaricides.

KEY WORDS: Rhipicephalus pulchellus , tick behavior, livestock disease, Ixodidae