Tick burden on European roe deer (Capreolus capreolus)

Abstract

In our study we assessed the tick burden on roe deer (Capreolus capreolus L.) in relation to age, physical condition, sex, deer density and season. The main objective was to find predictive parameters for tick burden. In September 2007, May, July, and September 2008, and in May and July 2009 we collected ticks on 142 culled roe deer from nine forest departments in Southern Hesse, Germany. To correlate tick burden and deer density we estimated deer density using line transect sampling that accounts for different detectability in March 2008 and 2009, respectively. We collected more than 8,600 ticks from roe deer heads and necks, 92.6% of which were Ixodes spp., 7.4% Dermacentor spp. Among Ixodes, 3.3% were larvae, 50.5% nymphs, 34.8% females and 11.4% males, with significant seasonal deviation. Total tick infestation was high, with considerable individual variation (from 0 to 270 ticks/deer). Adult tick burden was positively correlated with roe deer body indices (body mass, age, hind foot length). Significantly more nymphs were found on deer from forest departments with high roe deer density indices, indicating a positive correlation with deer abundance. Overall, tick burden was highly variable. Seasonality and large scale spatial characteristics appeared to be the most important factors affecting tick burden on roe deer.

Fig. 1

Location of the study sites in Southern Hesse, Germany

Fig. 2

Screened parts of roe deer (1 = head, 2 = neck). Drawing: W. Tambour

Fig. 3

Numbers of Ixodes (Ix) and Dermacentor (D) larvae, nymphs, females and males (a), and total Ixodes and Dermacentor numbers on roe deer heads vs. necks (b). Figures are given as means + standard errors; n = numbers of investigated roe deer

Fig. 4

Seasonal variation of tick burden on roe deer. Data are given as means with standard error, n _May = 69, n _July = 11, n _September = 42