“…Finally, testosterone may suppress immune function (Greives et al, 2006;Martin et al, 2008), either directly or indirectly by influencing the secretion of other hormones (Owen-Ashley et al, 2004;Poiani et al, 2000). This immunosuppressive effect, albeit not universal (Wingfield et al, 2001;Roberts et al, 2004), has led many to regard testosterone as a key mechanism underlying the trade-off between reproductive effort and survival (Folstad and Karter, 1992;Sheldon and Verhulst, 1996;Zera and Harshman, 2001;Hau, 2007).…”