Author Contributions
D.S. conceived and financed the project. A.G.R., M.U. and D.S. collected samples in the field. A.G.R. and M.F.R. contributed to lab procedures. A.M.M. performed the data analysis. A.M.M. and A.G.R. interpreted the results. A.G.R. wrote the first draft, O.L. and D.S. revised successive versions, and all authors improved and approved the final manuscript.