This paper describes results from ensembles of hybrid simulations of steady, homogeneous, collisionless plasmas characterized by average solar wind parameters near 1 AU upon which damped, resonant Alfvén-cyclotron fluctuations are imposed. The applied fluctuations propagate parallel to the background magnetic field B _o . The ensembles yield late-time proton and alpha particle responses to such fluctuations as functions of the initial magnitude of the applied fluctuating magnetic field energy and the initial v _αp /v _A (where v _αp is the alpha/proton relative speed and v _A is the Alfvén speed). The simulations show a strong, consistent negative correlation between the alpha temperature anisotropy T _α/T _α (where the directional subscripts refer to directions perpendicular and parallel to B _o ) and v _αp /v _A . On average the simulations also show a weaker, positive correlation between the proton temperature anisotropy and v _αp /v _A . Both correlations are in agreement with statistical observations from the solar wind near 1 AU, thereby confirming earlier conclusions that such observations are signatures of Alfvén-cyclotron scattering of ions in the solar wind.