Parasites and wildlife in a changing world: The vector-host- pathogen interaction as a learning case

Rizzoli, Annapaola; Tagliapietra, Valentina; Cagnacci, Francesca; Marini, Giovanni; Arnoldi, Daniele; Rosso, Fausta; Rosà, Roberto

Two other parameters determining the vectorial capacity, namely the extrinsic incubation period and the biting rate, are strongly influenced by temperature. In fact, the extrinsic incubation period n is shorter and the biting rate a is larger with warmer conditions (Reisen et al., 2006; Ewing et al., 2016) . Since some mosquito species are generalist and express opportunistic feeding behaviour, while others are specialists and feed preferentially on selected hosts (Burkett-Cadena et al., 2008; Farajollahi et al., 2011) , we remark that the mosquito biting rate can also be influenced by the avian density and heterogeneity, which are sensitive to environmental changes as we have observed above. Studies of mosquito feeding preferences have been essential to understand the ecology of WNV. In fact, at a population level, such feeding preferences may enhance or reduce transmission if vectors feed on competent or incompetent hosts, respectively (Carver et al., 2009; Marini et al., 2017) . Combining analysis of host preference, abundance, host behaviour and reservoir competence, Kilpatrick et al. (2006) demonstrated that the American robin (Turdus migratorius) acted as an unexpected 'super-spreader' of the WNV in North America. In Europe, for the first time, Rizzoli et al. (2015) demonstrated a clear feeding preference for the common blackbird (Turdus merula), both for wild collected specimens and in the lab, suggesting a potential important role for this species in the WNV epidemiology in Northern Italy. In addition, they found that later in the mosquitoes activity season (from July to October), the abundance of blackbird drops significantly and Cx. pipiens s.l. preferences shift toward the Eurasian magpie (Pica pica), especially in sites closer to human settlements, indicating that this species may contribute to WNV seasonal spill-over events to human and domestic animal species .