The main goal of this project is to contribute to a fundamental question in biology: how social and cooperative behaviors are maintained by natural selection in vertebrates. The research will attempt to determine if benefits of group living are indirectly obtained by helping close relatives to survive and reproduce or if benefits are directly obtained from mutual interactions between individuals, regardless of kinship. Those hypotheses will be tested in the Ocellated Antbird at La Selva Biological Station, Costa Rica. Ocellated Antbirds are social and feed exclusively on arthropods flushed by marching swarms of nomadic army ants during the day. The ants are difficult to monitor because they often move at night, so that finding them is a problem for the birds. Preliminary data suggest that these birds follow neighbors to find swarms (cooperative food searching). The data also show that foraging birds are aggressive towards some individuals but not others. Mutual tolerance of neighbors at swarms would provide access to food. Cooperative food searching will be tested by removing army ant colonies at night and tracking radio-tagged birds until they find new colonies. Molecular markers are being used to investigate whether neighbors are close relatives. Simulated presence of neighbors and strangers with different degrees of relatedness to focal foraging birds will be accomplished with recorded vocalizations to evaluate whether these birds are able to identify relatives or neighbors and allocate tolerance accordingly.
The intellectual merits of the proposed research are the assessment of benefits of group living and sociality through the evaluation of a novel mechanism of cooperation under natural conditions. In addition, this study will improve current knowledge on the behavior of obligate army-ant-following birds. This information is important because these are the most sensitive birds to forest fragmentation in the tropical forests that they inhabit. Future conservation strategies could be improved by taking their social behavior into account.
This project has broad impacts to society in the form of education. The project has and will continue to provide education and training to students with limited access to research opportunities in science. The investigators of this project have and will continue to offer educational talks to undergraduates that cannot come to La Selva, and to children, teenagers, and local naturalist guides in and around the protected areas. The latter group greatly benefits and appreciates new information coming from biologists working in the same areas where they work, and they pass this information along to the local communities and to ecotourists.
