Ness J. H., A mutualism’s indirect costs: the most aggressive plant bodyguards also deter pollinators, Oikos, 2006, 113(3):506-514, doi: 10.1111/j.2006.0030-1299.14143.x
A study of the relationship of Ferocactus wislizeni with four ant species and flower-visiting bees on Tumamoc Hill in Arizona. It includes worker responses to petals, observations of flower occupation, bee visit duration and seed parameters. It describes the cost of deterring pollinators at different levels of protection. Ant species were compared on naturally occupied plants.