Collective Action Promoted by Key Individuals
2018 (English)In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 192, no 4, p. 401-414Article in journal (Refereed) Published
Abstract [en]
Explaining why individuals participate in risky group behaviors has been a long-term challenge. We experimentally studied the formation of groups of birds (mobs) that aggressively confront predators and avian nest parasites and developed a theoretical model to evaluate the conditions under which mobs arise. We presented taxidermied mounts of predators on adult birds (hawks and owls) and of nest threats (crows and cuckoos) at different distances to nests of Phylloscopus warblers. Even when alone, birds are aggressive toward predators of adult birds, both at and away from their nests. By contrast, birds aggressively confront nest threats alone only when they have a nest nearby. However, strong initial responses by nest owners lead individuals without nearby nests to increase their responses, thereby generating a mob. Building on these findings, we derive the conditions in which individuals are incentivized to invest more when joining a high-gain individual compared to when acting alone. Strong responses of high-gain individuals acting alone tend to reduce the investments of other high-gain individuals that subsequently join. However, individuals that benefit sufficiently little from acting alone increase their investments when joining a high-gain individual and can even be sufficiently incentivized to join in when they would otherwise not act alone. Together, these results suggest an important role for key individuals in the generation of some group behaviors.
Place, publisher, year, edition, pages
UNIV CHICAGO PRESS , 2018. Vol. 192, no 4, p. 401-414
Keywords [en]
antipredator behavior, by-product mutualism, collective action, cooperation, group formation, mobbing behavior
National Category
Zoology
Identifiers
URN: urn:nbn:se:uu:diva-365285DOI: 10.1086/698874ISI: 000444262900003PubMedID: 30205027OAI: oai:DiVA.org:uu-365285DiVA, id: diva2:1262836
2018-11-132018-11-132018-11-13Bibliographically approved