Resumen

ZANOTTO, FLAVIA P.  y  BICUDO, J.E.P.W.. Dietary protein and carbohydrate affect feeding behavior and metabolic regulation in hummingbirds (Melanotrochilus fuscus). Rev. chil. hist. nat. [online]. 2005, vol.78, n.2, pp. 281-294. ISSN 0716-078X.  doi: 10.4067/S0716-078X2005000200012.

The objective of this work was to link hummingbird feeding behavior with metabolic regulation and in addition to assess whether dietary composition would affect entrance into torpor. Hummingbirds were fed a combination of diets with contrasting amounts of protein and carbohydrate. The diets were composed of the following: 2.4 % protein (P) - 12 % sucrose (S) and 0.8 % protein (P) - 36 % sucrose (S). The main findings showed that periods of feeding on each of the diets could be distinguished as separate bouts or feeding events. Hummingbirds presented to high protein-low carbohydrate diets (2.4P-12S) ingested a larger volume of diet, fed for longer (both around 1.7x) and increased the interval between feedings compared with hummingbirds fed diets 0.8P-36S. Physiological regulation between feeding events, on the other hand, was achieved through an increase in metabolic rate for low protein-high sugar diets (0.8P-36S). This response could probably be related to high sucrose assimilation rates through the digestive system of hummingbirds, a process already known to be very efficient in these birds. Additionally, there was a steeper decrease in oxygen consumption for hummingbirds fed diets 2.4P-12S during fasting and a suggestion of a higher torpor incidence in birds fed these diets

Palabras clave : hummingbird feeding; carbohydrate and protein interaction; unbalanced diet; feeding behavior; torpor.