title: Comparative off-host survival of larval Rocky Mountain Wood Ticks (Dermacentor andersoni) collected from ecologically distinct field populations.
abstract: Dermacentor andersoni (Ixodida: Ixodidae) Stiles, also known as the Rocky Mountain Wood Tick (RMWT), is found throughout the western United States and transmits pathogens of importance to human and animal health. The distributions and activity patterns of RMWTs are shaped by regional climatic variation. However, it is unknown if responses to climatic variation differ across the tick's geographical range. The objective of this narrow study was to test the hypothesis that the responses of RMWTs to abiotic conditions [e.g. temperature and RH (relative humidity)] vary among populations. We collected RMWTs from ecologically distinct field sites in the states of Montana and Oregon (USA). In the laboratory, we tracked weekly survival of tick larvae under four combinations of RH (75% and 98%) and temperature (26 and 32 °C) that reflected the range of conditions observed in the source habitats during spring-summer. For both populations, larval survival time decreased at the higher ambient temperature (50% mortality 1-2 weeks earlier). Differences in RH did not affect the survival time of larvae from Oregon. By contrast, the survival time of larvae from Montana decreased at the lower RH (50% mortality 1 week earlier). These data suggest that the tolerance limits for water stress may differ among populations of D. andersoni.
authors.affiliation: Department of Entomology, Washington State University, Pullman, WA, U.S.A.
authors.forename: J P
authors.initials: JP
authors.lastname: Owen
authors.forename: A
authors.initials: A
authors.lastname: Vander Vliet
authors.forename: G A
authors.initials: GA
authors.lastname: Scoles
mesh_terms: D000818:Animals; D003870:Dermacentor / Q000254:growth & development / Q000502:physiology*; D004777:Environment; D006813:Humidity; D007814:Larva / Q000502:physiology; D008136:Longevity; D009009:Montana; D009922:Oregon; D013312:Stress, Physiological; D016019:Survival Analysis; D013696:Temperature
keywords: Anaplasma; abiotic effects; geographical variation; ixodid tick; stress