Suchergebnisse

A groundbreaking new perspective on collective behavior across biological systemsCollective behavior is everywhere in nature, from gene transcription and cancer cells to ant colonies and human societies. It operates without central control, using local interactions among participants to allow groups to adjust to changing conditions. The Ecology of Collective Behavior brings together ideas from evolutionary biology, network science, and dynamical systems to present an ecological approach to understanding how the interactions of individuals generate collective outcomes.Deborah Gordon argues that the starting point for explaining how collective behavior works in any natural system is to consider how it changes in relation to the changing world around it. She shows how feedback use-the means by which networks of interactions operate-and the organization of interaction networks evolve to reflect the stability and demands of the environment. Ant colonies function collectively, and the enormous diversity of species in different habitats provides opportunities to look for general ecological patterns. Through an in-depth comparison of ant species, Gordon identifies broad trends in how the diversity of collective behavior in many other collective systems reflects the dynamics of the environment.Shedding light on how individual actions give rise to group behavior, The Ecology of Collective Behavior explains the evolution of collective behavior through innovation in participant interactions, offering new insights into how collective responses function in changing conditions

Protection mutualisms mediate trophic interactions in many systems, but their effects on the surrounding community are rarely studied. Ant-plant symbioses are classic examples of protection mutualisms: myrmecophytic plants provide nesting space and food for symbiotic ants in exchange for ant defense. Ant defense should thus reduce the abundance of herbivores, but studies of ant-plant symbioses usually measure damage to the plant without quantifying the herbivores themselves. In this study, we investigated whether geographic variation in the quality of ant defense in a symbiotic mutualism between Cordia alliodora trees and Azteca ants was associated with the abundance and species richness of plant herbivore communities. In three tropical-dry-forest sites in Middle America, we found that the density of Azteca ants within trees was negatively associated with the levels of leaf herbivory. At sites where ants were effective tree defenders, tree herbivores were less abundant and herbivore assemblages on trees exhibited lower species richness than at a site where ants were poor defenders. In addition, in a site where ants reduced herbivory, herbivore communities were less abundant and diverse in the presence of ants than in their absence, where as in a site where ants did not reduce herbivory, there were no differences in herbivore abundance or richness between trees with or without ants. We conclude that geographic variation in the quality of ant defense drives variation in myrmecophytic-plant herbivore communities. Moreover, ant-plant protection mutualisms should have important but rarely considered effects on herbivore population dynamics and food-plant specialization.