Comparative population dynamics of a generalist (Ixodes ricinus) and specialist tick (I. hexagonus) species from European hedgehogs

Abstract

Although the population dynamics of the tick Ixodes ricinus are relatively well studied, those of other Western European tick species are largely unknown. Moreover, there is very little information related to the interactions between I. ricinus and other ticks. Such knowledge, however, is of special interest in respect to the epidemiology of tick-borne pathogens such as Borrelia spp. We compared the dynamics of the generalist I. ricinus with the nest-dwelling hedgehog specialist, I. hexagonus. Both species were collected from hedgehogs from a naturally infested experimental population between 2006 and 2008. Ticks were collected once a month from March to October from each hedgehog counted and the life history stage and species determined. All hedgehogs harboured both tick species. Nymphs, females and males of I. ricinus showed clear bimodal seasonal distributions with peaks in spring and autumn, while larvae peaked only in summer. The density of I. hexagonus life stages was low during the whole investigation period and seasonal fluctuations of population density were much weaker compared to I. ricinus. Nymphs and larvae showed comparatively little change in population size and no consistent period of peak density. Females showed a single peak in summer and males were found only occasionally on hedgehogs. We suggest density-dependent mechanisms regulating the population density of the specialist I. hexagonus but not of the generalist I. ricinus.

Abiotic and Biotic Factors Associated with Tick Population Dynamics on a Mammalian Host: Ixodes hexagonus Infesting Otters, Lutra lutra

“…The prevalence of I. hexagonus on otters is, however, high in comparison to its prevalence on the domestic dog in the UK (5.6%, n = 3534 [34]). Further, the mean intensity (the total number of parasites of a particular species found in a sample divided by the number of infested hosts [35]) of ticks is higher on otters (7.2 per host) than on hedgehogs (3.8 [36]) despite examination of cadavers in the current study and live hosts in the hedgehog study. This suggests that otters are a noteworthy host for I. hexagonus .…”

“…As far as we are aware, there are no previous records of temperature effects on I. hexagonus and the only long-term study on population dynamics of I. hexagonus indicates little seasonal variation and low-level abundance (on hedgehogs [36]). In general, however; temperature has a key role in driving tick development rates [17], [19] and so affects population dynamics [16], [17].…”

Melting pot of tick-borne zoonoses: the European hedgehog contributes to the maintenance of various tick-borne diseases in natural cycles urban and suburban areas

“…Hedgehogs can reach up to nine times higher densities in urban areas with parks and garden, than in rural areas, with lowest densities in forests and open grassland fields and agricultural land without cover such as shrubs or dead wood [30–32]. Since they are one of the most successful urban adapters, hedgehogs and I. hexagonus could contribute to the spread and persistence of pathogens in a (sub) urban habitat via secondary enzootic cycles, even when the contact between I. hexagonus and humans is low [15, 33]. …”

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“…On seeing from dorsal side mouthpart observed in anterior parts, palps and hypostome were short, basis capituli distinctly appeared hexagonal shape and length of palp was nearly equal to basis capituli. Several studies have been conducted worldwide which showed high prevalence of this ectoparasite on hedgehog [10,9,19] . This tick had high tendency to infect wild host and immature stages generally infest hedgehogs, gerbils and rodents [3] .…”