Mean flea counts from prairie dogs and their burrows in Utah (2000), New Mexico (2010-2012), and Montana (2016, 2019). Prairie dogs were live-trapped, anesthetized with isoflurane, and combed thoroughly for 30 or 45 seconds to remove and count fleas. Prairie dogs were allowed to recover from anesthesia and released at their trapping locations. Randomly selected prairie dog burrows were swabbed for fleas using a plumber’s snake to insert a white flannel-cloth as deep as possible into each tunnel; the cable was shook ~30 seconds, and the cloth was removed from the burrow and quickly sealed in a re-sealable zipper storage bag. Fleas were later removed from swabs and counted. Mean flea counts were calculated for each sampling site, and sampling interval, as the total number of fleas collected (from prairie dogs or burrows) divided by the total number of sampling occasions (combings or swabbings). Funding and logistical support were provided by the U.S. Geological Survey; Turner Endangered Species Fund; Turner Enterprises Incorporated; Colorado State University; Centers for Disease Control and Prevention; U.S. Fish and Wildlife Service; Charles M. Russell National Wildlife Refuge; Shortgrass Steppe Long-Term Ecological Research Project; National Science Foundation; and the U.S. Department of Defense Strategic Environment Research and Development Program.

Data on prairie dog densities, flea abundance on prairie dogs, and plague epizootics in Montana and Utah, USA, 2003-2005. Prairie dog species (PDspecies in the data file) included black-tailed prairie dogs (PDs) (BTPD, Cynomys ludovicianus) in north-central Montana, white-tailed PDs (WTPD, Cynomys leucurus) in eastern Utah, and Utah PDs (UPD, Cynomys parvidens) in southwestern Utah. Field research was completed by the U.S. Geological Survey, Fort Collins Science Center, and colleagues. We used summertime visual counts as an index to PD densities (Pddensity in the data file). For each plot, we counted PDs using binoculars and/or spotting scopes from a single location outside the plot that gave the best view of the entire plot and repeated these counts on three (usually consecutive) days. We began counts just after sunrise and continued to conduct repeated systematic scans of the plot until the counts declined to about half the peak number (usually by late morning as PDs went below ground for their typical mid-day break). We converted the counts to density estimates (counts per hectare [ha]).The estimate we used to calculate density was the highest count obtained from a plot for the 3 days within a given year. We analyzed data from colonies experiencing a plague epizootic during this particular study (with an epizootic defined as greater than or equal to 90% decline in PD density). We indexed annual population change (PDpopchgProportion in the data file) by subtracting the count density estimate of the year before a plague epizootic (t1) from the density estimate during an epizootic (t2) for each plot, and dividing that by the density estimate from t1 to summarize population change as a proportionate change. We evaluated the correlation between PD population change and PD density in year t1, because negative plague-effects and the intensity of population decline may be greatest when PD densities are high in year t1 (a potential "density dependent" phenomenon discussed in a wide range of literature on disease ecology). We also evaluated the correlation between PD population change and flea abundance in year t1, because rates of plague transmission and, therefore, PD mortality are expected to increase with increasing flea densities. To assess flea abundance (PDfleas in the data file), we combed live-trapped PDs and counted the number of fleas on each PD. The PDs were live-trapped, individually marked with ear tags, and combed as thoroughly as possible for 30 seconds (s) to collect fleas. Prairie dogs were allowed to recover from anesthesia and released at their trapping locations. For each plot and year, we used the average value of flea counts (defined as flea abundance).

Data on flea parasitism and annual re-encounters of Utah prairie dogs at 5 colonies on the Awapa Plateau, Utah, USA, June-August 2013-2016. Utah prairie dogs were live-trapped and sampled on 5 colonies along an elevation gradient from 2,645 m to 2,873 m. Upon first capture each year, we anesthetized each prairie dog and fleas on its body and combed the prairie dog as thoroughly as possible for 30 s to collect fleas. We recorded the age (juvenile/adult), sex, and mass (nearest 5 g) of each prairie dog and marked its ears and body with metal tags and passive integrated transponders, respectively, for permanent identification. We indexed each prairie dog's body condition as the ratio between its weight and hind-foot length (nearest 0.10 cm) (weight:foot). Prairie dogs were allowed to recover from anesthesia and released at their trapping locations. Precipitation data for individual prairie dog colonies each year (February through September) are from the Parameter-Elevation Relationships on Independent Slopes Model (Daly et al. 2008; http://www.prism.oregonstate.edu/). The first set of data, Awapa UPD Fleas, includes data on the abundance of fleas on individual Utah prairie dogs. Each line of data is from an individual animal. Data include Utah prairie dog Age and Sex, prairie dog Condition, abundance of Fleas on the prairie dog, precipitation of the prior year (PriorPRISM), and precipitation of the current year (CurrentPRISM). The second set of data, Awapa UPD Reencounter, includes data on annual reencounters of individual Utah prairie dogs. Each line of data is for an individual prairie dog in a given annual interval; an animal must have been captured at the start of an interval to be included in that interval (e.g., a prairie dog captured in 2013 but not captured in 2014 was included in the interval 2013–2014 but was not included in the interval 2014–2015). The response variable (Reencounter) was binomial (e.g., a prairie dog captured in 2013 and 2014 but not in 2015 received a response of 1 for the interval 2013–2014 and a value of 0 for the interval 2014–2015). Predictor variables included: PriorPRISM, CurrentPRISM, prairie dog Age and Sex, prairie dog Condition, and flea parasitism of the prior year (expressed as detection/non-detection of at least 1 flea on a prairie dog in the prior year = FleaPrev). Data also include a information on trapping effort (i.e., number of trap days on a given colony) in the current year. Funding and logistical support were provided by the U. S. Geological Survey (USGS), Western Association of Fish and Wildlife Agencies, and Colorado State University. This research was also supported by Grant/Cooperative Agreement Number G14AC00403 from the USGS and Grant number RC-2634, Department of Defense Strategic Environmental Research and Development Program. Fieldwork was completed by the USGS Fort Collins Science Center, and lab work and flea identifications were completed by the USGS National Wildlife Health Center.

Data on flea parasitism and annual re-encounters of Utah prairie dogs at 5 colonies on the Awapa Plateau, Utah, USA, June-August 2013-2016. Utah prairie dogs were live-trapped and sampled on 5 colonies along an elevation gradient from 2,645 m to 2,873 m. Upon first capture each year, we anesthetized each prairie dog and fleas on its body and combed the prairie dog as thoroughly as possible for 30 s to collect fleas. We recorded the age (juvenile/adult), sex, and mass (nearest 5 g) of each prairie dog and marked its ears and body with metal tags and passive integrated transponders, respectively, for permanent identification. We indexed each prairie dog's body condition as the ratio between its weight and hind-foot length (nearest 0.10 cm) (weight:foot). Prairie dogs were allowed to recover from anesthesia and released at their trapping locations. Precipitation data for individual prairie dog colonies each year (February through September) are from the Parameter-Elevation Relationships on Independent Slopes Model (Daly et al. 2008; http://www.prism.oregonstate.edu/). The first set of data, Awapa UPD Fleas, includes data on the abundance of fleas on individual Utah prairie dogs. Each line of data is from an individual animal. Data include Utah prairie dog Age and Sex, prairie dog Condition, abundance of Fleas on the prairie dog, precipitation of the prior year (PriorPRISM), and precipitation of the current year (CurrentPRISM). The second set of data, Awapa UPD Reencounter, includes data on annual reencounters of individual Utah prairie dogs. Each line of data is for an individual prairie dog in a given annual interval; an animal must have been captured at the start of an interval to be included in that interval (e.g., a prairie dog captured in 2013 but not captured in 2014 was included in the interval 2013–2014 but was not included in the interval 2014–2015). The response variable (Reencounter) was binomial (e.g., a prairie dog captured in 2013 and 2014 but not in 2015 received a response of 1 for the interval 2013–2014 and a value of 0 for the interval 2014–2015). Predictor variables included: PriorPRISM, CurrentPRISM, prairie dog Age and Sex, prairie dog Condition, and flea parasitism of the prior year (expressed as detection/non-detection of at least 1 flea on a prairie dog in the prior year = FleaPrev). Data also include a information on trapping effort (i.e., number of trap days on a given colony) in the current year. Funding and logistical support were provided by the U. S. Geological Survey (USGS), Western Association of Fish and Wildlife Agencies, and Colorado State University. This research was also supported by Grant/Cooperative Agreement Number G14AC00403 from the USGS and Grant number RC-2634, Department of Defense Strategic Environmental Research and Development Program. Fieldwork was completed by the USGS Fort Collins Science Center, and lab work and flea identifications were completed by the USGS National Wildlife Health Center.

Data on annual population change for prairie dogs in Montana and Utah, USA, 2000-2005. Prairie dog species included black-tailed prairie dogs (PDs) (BTPD, Cynomys ludovicianus) in north-central Montana, white-tailed PDs (WTPD, Cynomys leucurus) in eastern Utah, and Utah PDs (UPD, Cynomys parvidens) in southwestern Utah. Field research was completed by the U.S. Geological Survey, Fort Collins Science Center, and colleagues. Data were collected on paired plots. Each pair included a plot treated annually with deltamethrin dust for flea control and plague mitigation and a plot left untreated as baselines. Paired plots had similar ecological features on the same (split) or nearby (separate) colonies. One plot within each pair was randomly selected for deltamethrin dust treatment. We used summertime visual counts as an index to PD population size.We conducted visual counts annually during June-August, after young PDs were aboveground. We used binoculars and spotting scopes to systematically and repeatedly scan the plots (each plot was 3-9 hectares in area), beginning just after sunrise and continuing until warming temperatures caused a decline in counts. We repeated the procedure for three days, using for analysis the highest count obtained. We counted from the same locations each year, simultaneously counting treated and non-treated plots of each pair. Visual counts were transformed into values of finite population change by dividing the PD count at the end of an annual interval by the count at the beginning of the interval. For example, if year is 2001, then population change was for the interval 2000 to 2001. Primary funding was provided by the U.S. Fish and Wildlife Service, U.S. Geological Survey, and Bureau of Land Management, supplemented by the Utah Division of Wildlife Resources and the Utah Department of Natural Resources Endangered Species Mitigation Fund. In-kind support was provided by the Bryce Canyon National Park, Dixie National Forest and BLM offices in Utah (Vernal, Cedar City, Richfield, and Torrey), Colorado (Meeker), and Montana (Malta). R. Reading and B. Miller of the Denver Zoological Foundation provided logistical support for parts of the study.

Data on annual population change for prairie dogs in Montana and Utah, USA, 2000-2005. Prairie dog species included black-tailed prairie dogs (PDs) (BTPD, Cynomys ludovicianus) in north-central Montana, white-tailed PDs (WTPD, Cynomys leucurus) in eastern Utah, and Utah PDs (UPD, Cynomys parvidens) in southwestern Utah. Field research was completed by the U.S. Geological Survey, Fort Collins Science Center, and colleagues. Data were collected on paired plots. Each pair included a plot treated annually with deltamethrin dust for flea control and plague mitigation and a plot left untreated as baselines. Paired plots had similar ecological features on the same (split) or nearby (separate) colonies. One plot within each pair was randomly selected for deltamethrin dust treatment. We used summertime visual counts as an index to PD population size.We conducted visual counts annually during June-August, after young PDs were aboveground. We used binoculars and spotting scopes to systematically and repeatedly scan the plots (each plot was 3-9 hectares in area), beginning just after sunrise and continuing until warming temperatures caused a decline in counts. We repeated the procedure for three days, using for analysis the highest count obtained. We counted from the same locations each year, simultaneously counting treated and non-treated plots of each pair. Visual counts were transformed into values of finite population change by dividing the PD count at the end of an annual interval by the count at the beginning of the interval. For example, if year is 2001, then population change was for the interval 2000 to 2001. Primary funding was provided by the U.S. Fish and Wildlife Service, U.S. Geological Survey, and Bureau of Land Management, supplemented by the Utah Division of Wildlife Resources and the Utah Department of Natural Resources Endangered Species Mitigation Fund. In-kind support was provided by the Bryce Canyon National Park, Dixie National Forest and BLM offices in Utah (Vernal, Cedar City, Richfield, and Torrey), Colorado (Meeker), and Montana (Malta). R. Reading and B. Miller of the Denver Zoological Foundation provided logistical support for parts of the study.

Data on the degree and duration of deltamethrin flea control on prairie dog colonies, with 3 prairie dog species at 6 sites across 3 US states. Fleas were combed (COMB) from live-trapped prairie dogs or swabbed (SWAB) from prairie dog burrows on non-treated (Non) sites and nearby sites treated with deltamethrin dust for flea control (Dusted). Each line of data is from an individual prairie dog or burrow. The first set of data, Shortterm BACI, includes data from before-after-control-impact (BACI) experiments comparing the abundance of fleas on prairie dogs at paired non-treated and treated sites in 2 time intervals: before treatments (Before) and 2 to 65 days after treatments (After). The second set of data, Moderate 1 year, includes data on the abundance of fleas on prairie dogs at paired non-treated and treated sites 7 to 13 months after treated sites had been treated with deltamethrin dust. The third set of data, Longterm 2 year, includes data on the abundance of fleas on prairie dogs (COMB) and in burrows (SWAB) at paired non-treated and treated sites 21 to 24 months after treated sites had been treated with deltamethrin. The fourth set of data, Dust days and grams, includes data on the abundance of fleas on prairie dogs at treated sites 7 to 13 months after deltamethrin treatments, and is restricted to sites with known amounts of dust (average grams) infused into prairie dog burrows. Funding and logistical support were provided by U. S. Fish and Wildlife Service; U. S. Geological Survey; U. S. Forest Service; Bureau of Land Management; Denver Zoological Foundation; Utah Division of Wildlife Resources and the Utah Department of Natural Resources Endangered Species Mitigation Fund; Bryce Canyon National Park; Badlands National Park; Dixie National Forest; Bureau of Land Management offices in Utah (Vernal, Cedar City, Richfield, and Torrey), Colorado (Meeker), and Montana (Malta); Colorado State University; Prairie Wildlife Research; National Fish and Wildlife Foundation; World Wildlife Fund; and Centers for Disease Control and Prevention.

Data on the degree and duration of deltamethrin flea control on prairie dog colonies, with 3 prairie dog species at 6 sites across 3 US states. Fleas were combed (COMB) from live-trapped prairie dogs or swabbed (SWAB) from prairie dog burrows on non-treated (Non) sites and nearby sites treated with deltamethrin dust for flea control (Dusted). Each line of data is from an individual prairie dog or burrow. The first set of data, Shortterm BACI, includes data from before-after-control-impact (BACI) experiments comparing the abundance of fleas on prairie dogs at paired non-treated and treated sites in 2 time intervals: before treatments (Before) and 2 to 65 days after treatments (After). The second set of data, Moderate 1 year, includes data on the abundance of fleas on prairie dogs at paired non-treated and treated sites 7 to 13 months after treated sites had been treated with deltamethrin dust. The third set of data, Longterm 2 year, includes data on the abundance of fleas on prairie dogs (COMB) and in burrows (SWAB) at paired non-treated and treated sites 21 to 24 months after treated sites had been treated with deltamethrin. The fourth set of data, Dust days and grams, includes data on the abundance of fleas on prairie dogs at treated sites 7 to 13 months after deltamethrin treatments, and is restricted to sites with known amounts of dust (average grams) infused into prairie dog burrows. Funding and logistical support were provided by U. S. Fish and Wildlife Service; U. S. Geological Survey; U. S. Forest Service; Bureau of Land Management; Denver Zoological Foundation; Utah Division of Wildlife Resources and the Utah Department of Natural Resources Endangered Species Mitigation Fund; Bryce Canyon National Park; Badlands National Park; Dixie National Forest; Bureau of Land Management offices in Utah (Vernal, Cedar City, Richfield, and Torrey), Colorado (Meeker), and Montana (Malta); Colorado State University; Prairie Wildlife Research; National Fish and Wildlife Foundation; World Wildlife Fund; and Centers for Disease Control and Prevention.

We collected fleas from black-tailed prairie dogs (Cynomys ludovicianus) on Buffalo Gap National Grassland and Badlands National Park, South Dakota, 2020-2022. We anesthetized trapped prairie dogs (and their fleas) with isoflurane in induction chambers for processing. We combed each individual with a fine-tooth comb for 30 seconds to remove and count fleas. We released all animals, after they were recovered from anesthesia, at the location where they were captured. Total flea counts from individual prairie dogs were considered an index of flea abundance. During 2018-2020, we provided prairie dogs on 21 sites with grain bait, laced with fipronil (0.005% by weight) by placing 1/2 cup or 1/4 cup of grain at each prairie dog burrow opening on the treated sites; 18 non-treated sites functioned as experimental baselines. In 2020–2022, we live-trapped, anesthetized, and combed prairie dogs for fleas. The data release contains two spreadsheets. The first spreadsheet (FipronilNoneComparison.csv) includes data from captures and combings of individual prairie dogs on treated and non-treated sites and lists the following information for each prairie dog: DATE (date of sampling), TREATMENT (fipronil grain or none), and FLEAS (the number of fleas combed from the prairie dog). These data were used to evaluate the effect of fipronil grain on prairie dog fleas. The second spreadsheet (DaysSinceFipronil.csv) includes data from captures and combings of prairie dogs on the treated sites only, in 2020 and 2022 (when decent numbers of fleas were found on prairie dogs at the treated sites), and lists the following information for each prairie dog: YEAR (2020 or 2022), DAYSSINCE (days since fipronil grain treatment), and FLEAS (the number of fleas combed from the prairie dog). These data were used to evaluate rebounding flea numbers on the treated sites over time (under the question, how long does it take for flea numbers to rebound on sites treated with fipronil grain?). Day of sampling was not included in this analysis, because that variable would have been confounded with DAYSSINCE.

We collected fleas from black-tailed prairie dogs (Cynomys ludovicianus) on Buffalo Gap National Grassland and Badlands National Park, South Dakota, 2020-2022. We anesthetized trapped prairie dogs (and their fleas) with isoflurane in induction chambers for processing. We combed each individual with a fine-tooth comb for 30 seconds to remove and count fleas. We released all animals, after they were recovered from anesthesia, at the location where they were captured. Total flea counts from individual prairie dogs were considered an index of flea abundance. During 2018-2020, we provided prairie dogs on 21 sites with grain bait, laced with fipronil (0.005% by weight) by placing 1/2 cup or 1/4 cup of grain at each prairie dog burrow opening on the treated sites; 18 non-treated sites functioned as experimental baselines. In 2020–2022, we live-trapped, anesthetized, and combed prairie dogs for fleas. The data release contains two spreadsheets. The first spreadsheet (FipronilNoneComparison.csv) includes data from captures and combings of individual prairie dogs on treated and non-treated sites and lists the following information for each prairie dog: DATE (date of sampling), TREATMENT (fipronil grain or none), and FLEAS (the number of fleas combed from the prairie dog). These data were used to evaluate the effect of fipronil grain on prairie dog fleas. The second spreadsheet (DaysSinceFipronil.csv) includes data from captures and combings of prairie dogs on the treated sites only, in 2020 and 2022 (when decent numbers of fleas were found on prairie dogs at the treated sites), and lists the following information for each prairie dog: YEAR (2020 or 2022), DAYSSINCE (days since fipronil grain treatment), and FLEAS (the number of fleas combed from the prairie dog). These data were used to evaluate rebounding flea numbers on the treated sites over time (under the question, how long does it take for flea numbers to rebound on sites treated with fipronil grain?). Day of sampling was not included in this analysis, because that variable would have been confounded with DAYSSINCE.