title: The influence of red deer space use on the distribution of Ixodes ricinus ticks in the landscape.
abstract: Many wingless ectoparasites have a limited capacity for active movement and are therefore primarily dependent on hitchhiking on their hosts for transportation. The distribution of the tick Ixodes ricinus is expected to depend mainly on transportation by hosts and tick subsequent survival in areas where they drop off. In Europe, the most important hosts of adult female I. ricinus are cervids. The extensive space use of large hosts provides a much larger dispersal potential for I. ricinus than that of smaller mammalian hosts. We aim to determine the contribution of red deer (Cervus elaphus) space use on the spatial distribution of I. ricinus, after accounting for landscape factors.
  
  
  
  We analysed the spatial distribution of I. ricinus with generalised mixed effects models (GLMMs) based on data from extensive field surveys of questing density in two coastal regions in Norway, from which home range data from 73 red deer with GPS collars were available. Red deer home ranges were derived using the kernel method to identify areas most frequently used by deer. We first fitted a baseline model with tick questing densities relative to landscape features that are likely to affect local climate conditions and hence, survival. We then added deer space use variables to the baseline model with only landscape variables to test whether areas more frequently used by red deer had higher questing tick densities.
  
  
  
  Questing I. ricinus density was predicted by several landscape features, such as elevation, distance to the fjord and topographic slope. In addition, we found that areas more heavily used within the red deer home ranges, correlated with higher questing tick densities. Increased effects of deer space use were additive to the landscape model, suggesting that correlations were more than just shared landscape preferences between deer and ticks.
  
  
  
  Our results imply that the distribution of I. ricinus is controlled by a complex set of factors that include both local conditions related to landscape properties that affect survival and how the large host population redistributes ticks. In particular, we have provided evidence that the local distribution of large hosts, with their extensive space use, redistributes ticks at the local scale.
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Qviller
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway.|Norwegian Veterinary Institute, P.O. Box 750, Sentrum, NO-0106, Oslo, Norway.
authors.forename: Hildegunn
authors.initials: H
authors.lastname: Viljugrein
authors.affiliation: Department of Ecology and Natural Resource Management, Norwegian University of Life Science, P.O. Box 5003, NO-1432, Aas, Norway.
authors.forename: Leif Egil
authors.initials: LE
authors.lastname: Loe
authors.affiliation: Department of Forestry and Forestry resources, Norwegian Institute of Bioeconomy Research, NO-6630, Tingvoll, Norway.
authors.forename: Erling L
authors.initials: EL
authors.lastname: Meisingset
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern, NO-0316, Oslo, Norway. atle.mysterud@ibv.uio.no.
authors.forename: Atle
authors.initials: A
authors.lastname: Mysterud
mesh_terms: D000818:Animals; D002980:Climate; D003670:Deer / Q000469:parasitology*; D018884:Ixodes / Q000254:growth & development*; D009664:Norway; D012621:Seasons; D062206:Spatial Analysis; D013984:Tick Infestations / Q000662:veterinary*
keywords: Cervid home range; Ixodes ricinus; Large hosts; Parasite distribution; Red deer; Risk maps; Spatial distribution; Species distribution modelling (SDM); Tick management; Ticks