Phylogenetic signals in ecological properties of parasites

Species evolved from common ancestors often share many features pertaining to a variety of traits (e.g. Hansen & Martins, 1996; Blomberg & Garland, 2002). The tendency for phylogenetically related species to resemble one another has been labelled variously ‘phylogenetic inertia’ (Wilson, 1975), ‘phylogenetic conservatism’ (Ashton, 2001), ‘phylogenetic correlation’ (Gittleman et al., 1996) and ‘phylogenetic effect’ (Derrickson & Ricklefs, 1988). Recently, Blomberg and Garland (2002) and Blomberg et al. (2003) have argued that the use of some of these terms suggests the action of certain evolutionary mechanisms, although such mechanisms cannot be inferred or estimated from comparative data. Instead, Blomberg and Garland (2002) and Blomberg et al. (2003) have recommended the use of the term ‘phylogenetic signal’ for this pattern because it does not imply any evolutionary mechanism or process that could have caused this resemblance. Indeed, simulations have demonstrated that different evolutionary processes may produce similar phylogenetic signals (Revell et al., 2008).