Using environmental factors to predict Rhipicephalus sanguineus s.l. (Acari: Ixodidae) mortality.

Abstract

Rhipicephalus sanguineus s.l. (Latreille, 1806) can establish indoor populations, which increases the risk of pathogen transmission to humans and companion dogs. Rhipicephalus sanguineus s.l. ticks spend most of their life cycle off the host, which subjects developmental timescale to abiotic factors. Previous studies showed that both temperature and relative humidity (RH) influenced R. sanguineus s.l. survival time across all life stages. However, quantified relationships between en3vironmental factors and R. sanguineus s.l. mortality is not currently available. Here, three R. sanguineus s.l. strains were evaluated for mortality under 20 combinations of five temperatures and four RHs. The data obtained were analyzed to quantify the relationship between environmental factors and R. sanguineus s.l. Mortality probabilities did not show a consistent pattern between the three tick strains. Temperature, RH, and their interaction influenced R. sanguineus s.l. mortality probabilities across all life stages, with mortality probability generally increasing with temperature but decreasing with RH. With 50% and lower RH, larvae cannot survive for more than one week. However, mortality probabilities in all strains and stages were more sensitive to temperature than to RH. This study identified the predictive relationship between environmental factors and R. sanguineus s.l. survival, which enables estimations of tick survival time under varied residential situations, allows parameterization of population models, and provides guidance for pest control professionals to develop efficient management strategies.