An experimental manipulation to simulate drought effects (grey columns) on vegetation structure revealed changes in selection acting on body size that were similar to those between naturally wet and dry years (EX and N refer to experimental vegetation removal and natural years respectively). Following experimental removal of vegetation, natural selection became strong and directional, favoring larger male body size (** indicates the significant selection gradient). We detected no significant selection on limb length. However, comparison of slopes revealed significant differences between vegetation removed and natural years (indicated by *).
Calsbeek et al. BMC Evolutionary Biology 2009 9:3 doi:10.1186/1471-2148-9-3