| In this paper, I discuss recent evidence concerning the adaptive significance of secondary metabolites in ripe fleshy fruits, and implications for seed dispersal by birds and other vertebrates. Specifically, I revisit a number of adaptive hypotheses originally presented and discussed by Cipollini & Levey in 1997, including the Attraction/Association, Seed Germination Effects, Attraction/Repulsion, Protein Assimilation, Gut Retention Time, Directed and General Toxicity, and Defense Tradeoffs hypotheses. I also present and discuss a new adaptive hypothesis, the Direct Nutritional Benefits hypothesis, posed to reflect recent discoveries concerning the positive dietary effects of some secondary metabolites. From this review, I conclude that focused... |
