LAUSR

The evolutionary stability of fruit-eating birds is linked to their role in dispersing seeds Mutually beneficial interactions between plants and frugivorous birds have evolved for at least 80 million years (1). Now, more than 70% of flowering plants rely on birds to disperse their seeds, and about 56% of bird families consume fruits as part of their diet (2, 3). Plants often have more than one seed disperser, and birds consume different types of fruits from different plant species, thus establishing a complex network of interactions. These networks can change considerably across space and time (4). Over short time spans, seed-dispersal interactions are dynamic and change in response to factors such as competition or abundance of the interacting partner (5, 6). However, the effects of evolutionary processes that take place over deep time are not clear (7). On page 733 of this issue, Burin et al. (8) suggest that evolutionary stability is associated with the specific role of the bird species in seed-dispersal networks.