The value of being a resource specialist: behavioral support for a neural hypothesis.
The neural hypothesis of diet breadth proposes that selecting an appropriate behavior is more efficient if simple or exaggerated cues can be used as a basis of decision making rather than making a choice among many complex sensory inputs. I propose that simple signals overcome the problem of multiple sensory inputs and the consequent need for the brain to decide among inputs from these multiple channels. Experiments on grasshoppers show that there is a significant time cost in having to make a choice, relative to situations in which individuals have grown accustomed to having no choice. Those with a choice were shown to be less decisive by two different measures than those without a choice. It is argued that the data, showing lengthy decision times as a result of having a choice, would involve a significant ecological risk. It is further argued that the reduced risk of quick decisions would favor specialization of resource use. The evolution of resource-specific cues that have often been called sign stimuli are considered critical elements of restricted resource use.
Bernays
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Department of Entomology and Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA.