Phylogenetic analysis of coadaptation in behavior, diet, and body size in the African antelope

Several authors have suggested that African antelope (familyBovidae) exemplify coadaptation of ecological, behavioral,and morphological traits. We tested four hypotheses relatedto the ecology and behavior of 75 species of African antelopeusing both conventional statistical techniques and techniques that account for the nonindependence of species by consideringtheir phylogenetic relationships. Specifically, we tested thehypotheses that (1) dietary selectivity is correlated negativelywith body mass, (2) dietary selectivity is correlated negativelywith group size, (3) gregarious species either flee or counterattackwhen approached by predators, but solitary and pair-livingspecies seek cover to hide, and (4) body mass and group sizeare correlated positively. Each of these hypotheses was examinedfor the global data set (family Bovidae) and, when possible,within the two antelope subfamilies (Antilopinae and Bovinae)and within 7 of the 10 antelope tribes. The results of ourconventional and phylogenetically corrected analyses supportedthe hypotheses that group and body size vary predictably with feeding style and that antipredator behavior varies with groupsize. The hypothesis that body mass and group size are correlatedpositively was supported by conventional statistics, but thesetwo traits were only weakly related using a phylogeneticallycorrected analysis. Moreover, qualitative and quantitativecomparisons within each of the eight major African antelope tribes generally gave little support for the four hypothesestested. Thus, although our analyses at the subfamily levelprovided results that were consistent with prior hypotheses,our analyses at the level of tribes were equivocal. We discussseveral possible explanations for these differences.