https://socictopen.socict.org/files/original/081655b9f115cdd616e4a89cdd156004.pdf b654a4311d13ada6dd3ba7e6b7808b4d Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Agricultura sostenible Description An account of the resource Dominio científico: Agricultura sostenible Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource The integration of diet, physiology, and ecology of nectar-feeding birds La integración de la dieta, fisiología, y ecología en aves nectarívoras Creator An entity primarily responsible for making the resource M. VICTORIA LOPEZ-CALLEJA, TODD J. McWHORTER Description An account of the resource Balance between energy acquisition and expense is critical for the survival and reproductive success of organisms. Energy budgets may be limited by environmental factors as well as by animal design. These restrictions may be especially important for small endotherms such as hummingbirds, which have exceedingly high energy demands. Many nectar-feeding bird species decrease food intake when sugar concentration in food is increased. This feeding response can be explained by two alternative hypotheses: compensatory feeding and physiological constraint. The compensatory feeding hypothesis predicts that if birds vary intake to maintain a constant energy intake to match energy expenditures, then they should increase intake when expenditures are increased. Broad-tailed hummingbirds (Selasphorus platycercus) and Green-backed fire crown hummingbirds (Sephanoides sephaniodes) were presented with diets varying in energy density and exposed to various environmental temperatures. Birds decreased volumetric food intake in response to sugar concentration. However, when they were exposed to lower environmental temperatures, and hence increased thermoregulatory demands, they did not increase their rate of energy consumption and lost mass. These results support the existence of a physiological constraint to the energy budgets of hummingbirds. Digestive and peripheral organ function limitations may impose severe challenges to the energy budgets of these small endotherms, and therefore play a significant role in determining their distribution, ecology, and natural history.El balance entre la adquisición y el uso de energía es crítico para la reproducción y sobrevivencia. Los presupuestos energéticos de los organismos pueden estar limitados tanto por factores ambientales como por su fisiología. Estas restricciones pueden ser especialmente importantes para pequeños endotérmos como los colibríes (picaflores) que tienen costos energéticos altos por unidad de masa. Muchas especies de aves nectarívoras reducen el consumo de alimento cuando la concentración de azúcar aumenta. Esta respuesta puede ser explicada por dos hipótesis alternativas: compensación alimenticia y restricciones fisiológicas. La primera hipótesis predice que las aves varían el consumo para mantener la ingesta de alimento ajustada a sus gastos energéticos. Por ende, cuando los gastos energéticos aumentan, el consumo debe aumentar. Colibríes vibradores (Selasphorus platycercus) y picaflores (Sephanoides sephaniodes) fueron alimentados con dietas de contenido energético variable y expuestos a varias temperaturas ambientales. Las aves redujeron el volumen consumido en respuesta a un incremento en la concentración de azúcar. Sin embargo, cuando fueron expuestos a bajas temperaturas, y por lo tanto a mayores demandas de termoregulación, no aumentaron su consumo de energía y perdieron masa corporal. Estos resultados indican la existencia de una limitante fisiología que restringe a los presupuestos energéticos de los colibríes. Limitaciones funcionales (digestivas o periféricas) pueden imponer seríos dilemas para los presupuestos de energía de estos pequeños endotérmos y por lo tanto jugar un papel significativo en su distribución, ecología, e historia natural. Date A point or period of time associated with an event in the lifecycle of the resource 2000 Subject The topic of the resource Energética, Feeding behavior, Nectarivory, conducta de alimentación, digestion, energetics, hummingbirds, nectarivoría, picaflores Source A related resource from which the described resource is derived Revista Chilena de Historia Natural Publisher An entity responsible for making the resource available BMC Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant Botany, Zoology Relation A related resource <a href="http://www.scielo.cl/scielo.php?script=sci_arttext&amp;pid=S0716-078X2000000300008" target="_blank" rel="noreferrer noopener">http://www.scielo.cl/scielo.php?script=sci_arttext&amp;pid=S0716-078X2000000300008</a>