The integration of multiple independent data reveals an unusual response to Pleistocene climatic changes in the hard tick Ixodes ricinus

Department of Ecological and Biological Sciences, Tuscia University, Viterbo, Italy.
Molecular Ecology (Impact Factor: 6.49). 02/2013; 22(6). DOI: 10.1111/mec.12203
Source: PubMed


In the last few years, improved analytical tools and the integration of genetic data with multiple sources of information have shown that temperate species exhibited more complex responses to ice ages than previously thought. In this study, we investigated how Pleistocene climatic changes affected the current distribution and genetic diversity of European populations of the tick Ixodes ricinus, an ectoparasite with high ecological plasticity. We first used mitochondrial and nuclear genetic markers to investigate the phylogeographic structure of the species and its Pleistocene history using coalescent-based methods; then we used species distribution modelling to infer the climatic niche of the species at last glacial maximum; finally, we reviewed the literature on the I. ricinus hosts to identify the locations of their glacial refugia. Our results support the scenario that during the last glacial phase, I. ricinus never experienced a prolonged allopatric divergence in separate glacial refugia, but persisted with interconnected populations across Southern and Central Europe. The generalist behaviour in host choice of I. ricinus would have played a major role in maintaining connections between its populations. Although most of the hosts persisted in separate refugia, from the point of view of I. ricinus, they represented a continuity of 'bridges' among populations. Our study highlights the importance of species-specific ecology in affecting responses to Pleistocene glacial-interglacial cycles. Together with other cases in Europe and elsewhere, it contributes to setting new hypotheses on how species with wide ecological plasticity coped with Pleistocene climatic changes.

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    • "In the last decades advances in molecular techniques have greatly improved our tools to investigate the dynamics of vector populations and of pesticide resistance insurgence [43, 49–53]. More recently, next-generation sequencing technologies have offered unprecedented opportunities to investigate the molecular basis of the interaction between cellular defenses and insecticides [54]. "
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    Parasites & Vectors 07/2014; 7(1):349. DOI:10.1186/1756-3305-7-349 · 3.43 Impact Factor
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    • "In some cases, the trade movements of livestock introduced and spread species far away from the original ranges [51]. We demonstrated that the covariates derived from the harmonic regression better captured the abiotic niche of several species of ticks than did the monthly raw set of descriptors or interpolated gridded climate, which have been traditionally used for this purpose [52-54]. We are aware that the nominal spatial resolution of 0.1° may be too coarse for some applications focusing on local or regional issues, which could require a higher resolution. "
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    Parasites & Vectors 07/2014; 7(1):302. DOI:10.1186/1756-3305-7-302 · 3.43 Impact Factor
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    PLoS ONE 10/2013; 8(10):e76930. DOI:10.1371/journal.pone.0076930 · 3.23 Impact Factor
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