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.