Ectoparasites in Two Diverse Habitats in Western Oregon I. Ixodes (Acarina: Ixodidae)1

Abstract

A study of the host range and distribution of ticks was undertaken in 2 forested areas of western Oregon. The ticks sampled from a coastal area, Neptune State Park (characterized by 150 to 200-year-old climax Sitka spruce-hemlock forest), were compared to those found in a mixed 2nd growth Douglas fir-oak forest in the Willamette valley. Ixodes angustus Neumann was the most common tick found on the coastal site. Ixodes soricis Gregson was less abundant in this area and I. pacificus Cooley & Kohls was absent. Immature stages of I. pacificus were found in moderate numbers in the valley sampling site in the summer and fall; I. angustus and soricis were also present. I. soricis was found only on shrews and shrew-moles in this study. The shrew tick was not found on other moles although immatures of I. angustus parasitized these hosts. Of the ticks examined in this study, I. pacificus is the only species that quests on vegetation or that feeds on larger animals including man. Immature stages of I. pacificus were collected from small mammal and lizard hosts in the valley sampling site.