Fig. 2

Assessment of initiation of infestation. Simulated mean proportions of landscape cells infested with off-host (potentially host-seeking) tick larvae per hectare on a hypothetical 10,000-ha ranch under weather conditions recorded in Willacy County, Texas, USA, from January 2009 through December 2018 (only week 24, 2009 through week 2, 2010 shown here): (i) on whole ranch (grey dash line), and in (ii) good (black line), (iii) fair (black dash line), and (iv) poor (grey line) tick habitats. Simulations assumed one infested head of cattle (a), white-tailed deer (b) and nilgai (c) was introduced at the intersection of patches of good, fair, and poor tick habitat in an otherwise SCFT-free ranch during week 25 of 2009. Tick hosts present on the ranch included cattle, white-tailed deer and nilgai. Thirty-one percent, 28 percent and 41 percent of the ranch was considered good, fair and poor habitat, respectively, for off-host tick larvae. Relative habitat use preferences of hosts for good, fair and poor tick habitats, respectively, were 0.30, 0.10 and 0.60 for cattle, 0.20, 0.40 and 0.40 for white-tailed deer, and 0.30, 0.10 and 0.60 for nilgai