Aspects of Host Finding by the Cattle Tick, Boophilus microplus.

Abstract

Experimental and theoretical studies on the rates of host finding by larvae of the cattle tick B. microplus are described. At stocking rates of about two beasts per hectare the cattle picked up between 30 and 70% of the larvae in a week, compared with 50 to 85% with five beasts per hectare. Each beast effectively picked up all the ticks from an area of 0.022-0.075 ha each day. The lower values were associated with lower minimum temperatures, a phenomenon which was attributed to reduced activity of the larvae. A simplified model was developed to investigate the sensitivity of the host-finding component of the tick's life system to the parameters controlling the process. It was found that the total proportion of larvae finding a host could be expressed as a function of the product of the host-finding rate and the median duration of survival of the larvae. Pasture spelling for tick control was also considered in relation to the parameters of the model.