Movement of and (Acari: Ixodidae) adult ticks in chaparral under natural conditions in Northern California, U.S.A.

The movement of and adult ticks down a hill slope under natural conditions was investigated using the mark-release-recapture (MRR) method. We evaluated the movement of host-seeking adult ticks down a hill slope to determine if ticks travel downhill from an uphill area to trail margins below. During the tick seasons in 2016-2018, the ticks were collected by flagging, marked with paint, released at a predetermined location, and recaptured by weekly flagging. Of the 188 female and 114 male marked and released 30 m above the trail in 2016, 11 (5.8%) females and one (0.9%) male were recaptured at the trail. In 2017, of the 71 female and 52 male , none were recaptured. In 2018, nine (3.6%) female and one (0.4%) male were recaptured of the 247 female and 287 males marked and released. Fifteen (18.5%) female and six (7.3%) male were recaptured of the 81 females and 82 males marked and released in 2017. The trail deterred further movement with only 0.6% of and 8.3% of recaptured on the opposite side of the trail. This study demonstrated that some and adults found along the uphill side of trails may have originated from an area 30 m from the trail margin, some travelling at a rate of 1.6-1.9 m/day under natural conditions in chaparral.