Do black colobus in mixed-species groups benefit from increased foraging efficiency?

Seed-eating in the African colobines varies according to species and site. Because seeds are more palatable than leaves, seed-eating is considered to result from a positive choice by colobines. A year-long study of the diet of Colobus satanas in Central Gabon confirmed that this species eats a significant amount of seeds. Furthermore, despite large variations in fruit availability, this amount consistently increases when colobines feed in mixed-species troops including frugivorous cercopithecines and mangabeys. Our results show that colobines benefit when feeding in mixed troops and suggest that polyspecific associations are an adaptive strategy that could have positive effects on colobine populations, especially during the period of fruit shortage.