Meeting Abstract

P3.142  Thursday, Jan. 6  Thermoregulatory cost affects territorial behavior in hummingbirds: A model and its application GONZALEZ-GOMEZ, Paulina L*; RICOTE-MARTINEZ, Natalia ; RAZETO-BARRY, Pablo; COTORAS, Ivania; BOZINOVIC, Francisco; Univ. of California, Davis; Instituto de Filosofia y Ciencias de la Complejidad, Santiago, Chile; CASEB, Pontificia Universidad Catolica de Chile.; Instituto de Filosofia y Ciencias de la Complejidad, Santiago, Chile ; IEB, Facultad de Ciencias, Universidad de Chile.; CASEB, Pontificia Universidad Catolica de Chile. plgonzalezgomez@ucdavis.edu

A common assumption in behavioral ecology is that the valuation of a resource by consumers depends on the energetic value of the resource itself. Nevertheless, the value of a resource may be relative to the condition of the organism, which is in turn related to the abiotic conditions such as ambient temperature. We developed a theoretical model – incorporating these untested assumptions – to predict a functional relation between territorial aggression and ambient temperature for individuals sensitive to daily variations in energy availability. We evaluated our theoretical predictions against a field experiment carried out with the hummingbird Sephanoides sephaniodes . The model predicted a quadratic relation between aggression intensity and ambient temperature. Field data were better explained by a quadratic equation than a linear function, suggesting the existence of lower and upper thresholds of temperature which determine the intensity of territorial defense. Ambient temperature affects energy expenditure for thermoregulation, and therefore it fixes the benefit level that must be produced by the territory to pay the costs of its defense. Our findings strongly suggest that abiotic conditions can change an animal valuation of the yield of a resource, and in turn influence the behavioral strategy which it adopts.