First assessment of ectoparasite prevalence in Apennine populations of Eurasian red squirrel: does habitat fragmentation affect parasite presence?

Although habitat fragmentation is widely reported to affect species survival anddistribution, its effect in terms of host-parasite interactions in small mammal communitiesis poorly studied yet. Using information collected from carcasses of 34 road-killand two preyed-upon individuals, we present the first comprehensive study dealingwith the relationship between habitat fragmentation and the presence of differentectoparasite species infecting a small Sciurus vulgaris population inhabiting theApennine ridge. We predicted that the probability to find individuals infested by parasiteswould be lower in highly fragmented areas because of the trade-off effects overboth mammal and ectoparasite communities. Our findings showed that the mostfrequent ectoparasites were the squirrel fleas Ceratophyllus sciurorum and hard ticksIxodes ricinus. Males showed higher presence of ectoparasites than females, probablybecause of different behaviour in space use and higher hormone levels, which maycompromise host's resistance to infection. As to the relationship with habitat fragmentation,we did not find support that individuals in highly fragmented areas would be lesssusceptible to C. sciurorum infestation because of lower red squirrel relative density.The presence of highly suitable habitat patches in fragmented habitats may havefavoured the presence of squirrels, hence promoting C. sciurorum transmissionamong specimens. Similarly, we did not find support that habitat fragmentationwould have reduced the likelihood of generalist ectoparasites transmission amongsquirrels. This finding may be explained by the increasing tolerance of generalistectoparasites towards habitat fragmentation because of the presence of species (e.g.,roe deer Capreolus capreolus) able to better exploit ecotonal areas. We believe that ourresearch provides interesting preliminary results on ectoparasites infesting red squirrelsin the Apennine area, and of the potential impact which habitat fragmentation mayhave on them. Nevertheless, the effect of habitat fragmentation over parasite communitiesis still poorly considered, and further researches are needed.