DOI: 10.5061/dryad.k6djh9wg9
title: Data from: Responses of juvenile blacklegged ticks (Acari: Ixodidae) to hosts of varying quality

description: Blacklegged ticks (Ixodes scapularis) are the most medically and
 economically important vectors in North America. Each of their three life
 stages requires a bloodmeal from one of many potential host species,
 during which they can acquire or transmit pathogens. Host species,
 however, vary tremendously in their quality for ticks, as measured by
 differences in feeding and molting success. There should be clear fitness
 benefits for ticks that preferentially feed upon high-quality hosts (e.g.,
 white-footed mice, Peromyscus leucopus), or at least avoid feeding on very
 low-quality hosts (e.g., Virginia opossums, Didelphis virginiana). Indeed,
 laboratory experiments have found some evidence of host preferences in I.
 scapularis; but these involve presenting ticks with hosts simultaneously
 and measuring movement towards hosts on a horizontal plane. In nature,
 however, host seeking ticks encounter hosts sequentially and their
 movements are principally in a vertical plane. Here, we present the
 results of a study in which we measured the vertical movements of
 host-seeking juvenile blacklegged ticks before and after a host (P.
 leucopus, Tamias striatus, Sciurus carolinensis, or D. virginiana) was
 present, and whether the strength of their responses vary with host
 quality. We found ticks did not measurably alter the speed of their
 vertical movement in the presence of any hosts, regardless of host
 quality. Both larvae and nymphs quested slightly higher in the presence of
 hosts, but this did not vary by host species. These results call into
 question the existence of active host preferences, at least in this stage
 of the host seeking process. Keywords: Vector Ecology, Ecology &
 Behavior, Ixodidae Entomological Society of America Editorial Office: 170
 Jennifer Road, Suite 230, Annapolis, MD 21401, USA. Editorial Office
 Phone: 1-301-731-4535.
description: # Responses of juvenile blacklegged ticks (Acari: Ixodidae) to hosts of
 varying quality These data come from an experiment designed to determine
 if larval and nymphal blacklegged ticks (*Ixodes scapularis*) alter their
 vertical movements (i.e., "questing") in the presence of hosts,
 and whether any changes in these behaviors scale with the quality of the
 host species. We used wild caught white-footed mice (*Peromyscus
 leucopus*), eastern chipmunks (*Tamias striatus*), gray squirrels
 (*Sciurus carolinensis*), and virginia opossums (*Didelphus virginiana*)
 as our host species, as these species span the spectrum from high-quality
 to very low-quality hosts. We placed ticks on clear, vertical rods, and
 tracked their locations on the rods without a host present, and then after
 a host was placed. ## Description of the data and file structure Data are
 measurements of either the average height or the total distance travelled
 in cm (converted to "speed" within the provided code) in the
 absence or presence of a host. We have separate data files for larva
 height, nymph height, larva speed, and nymph speed (four csvs). Each data
 file has the same structure and columns, with the exception of the columns
 "absent" and "present". The shared columns for each
 data frame are the following: - HostID: A unique identifier for each host
 individual. * TickID: An ID for each tick tracked in a single trial (these
 values are based on tick groups and rod number, they will repeat for
 different host individuals) * Ticks: A unique identifier for a single tick
 responding to a host individual, created by combining HostID & TickID.
 * Group: An ID for the vial ticks in a trial came from. Ticks with the
 same group ID were collected at the same time and held in the same vial
 for the duration of the experiment. * Species: Species of the host used in
 a trial (PL = Peromyscus leucopus, TS = Tamias striatus, SC = Sciurus
 carolinenses, DV = Didelphus virginiana). * Date: Date the trial was
 conducted. dflh.csv includes data measuring the average height of a larval
 tick on the rod in the absence and presence of a host individual. Each row
 is the average questing height of a single tick before and after the
 addition of a host. In addition to the above columns, this csv includes: *
 absent: Average height of a larval tick in the absence of any host. This
 measurement is scaled between 0 and 1, with 0 being the bottom of the rod
 where the clay base meets the water line, and 1 being the top of the rod.
 The rods used in larval experiments were 10cm tall. * present: Average
 height of a larval tick after the addition of a host. This measurement is
 scaled between 0 and 1, with 0 being the bottom of the rod where the clay
 base meets the water line, and 1 being the top of the rod. The rods used
 in larval experiments were 10cm tall. dfnh.csv includes data measuring the
 average height of a nymphal tick on the rod in the absence and presence of
 a host individual. Each row is the average questing height of a single
 tick before and after the addition of a host. In addition to the above
 columns, this csv includes: * absent: Average height of a nymphal tick in
 the absence of any host. This measurement is scaled between 0 and 1, with
 0 being the bottom of the rod where the clay base meets the water line,
 and 1 being the top of the rod. The rods used in nymphal experiments were
 13cm tall. * present: Average height of a nymphal tick after the addition
 of a host. This measurement is scaled between 0 and 1, with 0 being the
 bottom of the rod where the clay base meets the water line, and 1 being
 the top of the rod. The rods used in nymphal experiments were 13cm tall.
 dfls.csv includes data measuring the total distance a larval tick on
 travelled on the rod in the absence and presence of a host individual.
 Each row is the total distance travelled of a single tick before and after
 the addition of a host. In addition to the above columns, this csv
 includes: * absent: Total distance a larval tick travelled (in cm) in the
 absence of any host during the 6 minute observation period. * present:
 Total distance a larval tick travelled (in cm) in the presence of a host
 during the 6 minute observation period. dfns.csv includes data measuring
 the total distance a nymphal tick on travelled on the rod in the absence
 and presence of a host individual. Each row is the total distance
 travelled of a single tick before and after the addition of a host. In
 addition to the above columns, this csv includes: * absent: Total distance
 a nymphal tick travelled (in cm) in the absence of any host during the 6
 minute observation period. * present: Total distance a nymphal tick
 travelled (in cm) in the presence of a host during the 6 minute
 observation period. ## Code/Software All models are specified using Stan
 code (_.stan files) which are run in R. The Stan models are as follows: *
 mh1.stan: Height model with species specific host effect. * mh2.stan:
 Height model with generic (not species specific) host effect. * mh3.stan:
 Height model with no host effect. * ms1.stan: Speed model with species
 specific host effect. * ms2.stan: Speed model with generic host effect. *
 ms3.stan: Speed model with no host effect. The TickQuestingBehaviors.pdf
 and similar files contain the R code to run the above Stan models and
 generate paper figures.