Exploitation of an ant-plant mutualism by a cavity-nesting wasp

Background: stems in an agricultural habitat (oil palm plantation), than in heavily logged forest. We also predict that because wasps nest in the same plant structures as the mutualistic ants, plants with greater numbers of wasps should have smaller ant colonies (although note that ants might also exclude wasps). Any such reduction in ant colony size could then reduce the ability of the mutualistic ants to protect plants from herbivorous insects. Methods: plants. Results: was more frequent in oil palm plantations than in heavily logged forests. We also found that plants colonised by larger numbers of wasps had smaller protective ant colonies, although causal direction remained unclear. There was no evidence for reduced ant protection of plants from herbivores in conjunction with wasp colonisation. Taken together, our results indicate that anthropogenic habitat change can result in colonisation by an exploitative species that potentially disrupts mutualistic interactions through pre-emption of the resources traded by mutualistic partners.