Micrometeorologic factors affecting field host-seeking activity of adult Dermacentor variabilis (Acari: Ixodidae)

Fifteen micrometeorologic or microenvironmental parameters, including temperature, moisture, wind, and solar radiation, were repeatedly measured at 1 m and 2.5 cm aboveground, in the litter layer, and in the soil concurrently with drag samples of questing American dog tick, Dermacentor variabilis (Say), in five plots (1 by 10 m) in Delaware County, Ohio. Multivariate statistical analyses of the resultant data showed that ambient temperature was the best general predictor of adult tick host seeking under the observed ranges of the observed parameters. Multivariate procedures included forward stepwise multiple regressions and principal components analyses. Solar radiation was covariant with ambient temperature but was much less predictive. A suppression of questing activity with increased ambient temperature was evident at the highest observed temperatures, implying an upper temperature limit for this activity.