INVESTIGADORES
GALETTO Leonardo
artículos
Título:
Sugar preferences of the green-backed firecrown hummingbird (Sephanoides sephaniodes, Trochilidae): a field experiment.
Autor/es:
CHALCOFF, V., AIZEN, M. & GALETTO, L.
Revista:
AUK
Editorial:
AMER ORNITHOLOGISTS UNION
Referencias:
Año: 2008 vol. 125 p. 60 - 66
ISSN:
0004-8038
Resumen:
Abstract.?Many flowers associatedwith hummingbirds (Trochilidae) produce nectar rich in sucrose, a characteristic that reflects innate preferences or the metabolic capacities of their putative pollinators or both. However, studies on nectar sugar selectivity by hummingbirds in the field are lacking. Under natural field conditions, we studied the sugar preferences of the Green-backed Firecrown Hummingbird (Sephanoides sephaniodes), the southernmost hummingbird in the world and a key pollinator in the temperate forest of South America. We considered potential differences between males and females and the influence of environmental temperature on those preferences. To free-foraging Green-backed Firecrown Hummingbirds, we simultaneously offered four different sugar solutions with the same concentration (24% wt/wt): (1) sucrose, (2) glucose, (3) fructose, and (4) a 1:1:1 mixture of these three solutions, as well as a control of pure water. The experimental design involved three replicates per treatment assigned to three different ?blocks? of five feeders each, during eight periods of seven days each. We scored the number of Green-backed Firecrown Hummingbirds feeding on each feeder, the number of consumptions made by each individual, and the amount of sugar (g) consumed per sampling period. Greenbacked Firecrown Hummingbirds clearly discriminated against pure water, favoring sugar solutions; of the latter, they preferred sucrose over glucose and fructose.The mixed-sugar solution showed intermediate preference values. Neither sex nor temperature affected sugar preferences. Sugar preferences by the Green-backed Firecrown Hummingbird could influence the nectar composition of the flowers it pollinates through differential selection. Received 14 September 2006, accepted 25 February 2007. South America. We considered potential differences between males and females and the influence of environmental temperature on those preferences. To free-foraging Green-backed Firecrown Hummingbirds, we simultaneously offered four different sugar solutions with the same concentration (24% wt/wt): (1) sucrose, (2) glucose, (3) fructose, and (4) a 1:1:1 mixture of these three solutions, as well as a control of pure water. The experimental design involved three replicates per treatment assigned to three different ?blocks? of five feeders each, during eight periods of seven days each. We scored the number of Green-backed Firecrown Hummingbirds feeding on each feeder, the number of consumptions made by each individual, and the amount of sugar (g) consumed per sampling period. Greenbacked Firecrown Hummingbirds clearly discriminated against pure water, favoring sugar solutions; of the latter, they preferred sucrose over glucose and fructose.The mixed-sugar solution showed intermediate preference values. Neither sex nor temperature affected sugar preferences. Sugar preferences by the Green-backed Firecrown Hummingbird could influence the nectar composition of the flowers it pollinates through differential selection. Received 14 September 2006, accepted 25 February 2007. Sephanoides sephaniodes), the southernmost hummingbird in the world and a key pollinator in the temperate forest of South America. We considered potential differences between males and females and the influence of environmental temperature on those preferences. To free-foraging Green-backed Firecrown Hummingbirds, we simultaneously offered four different sugar solutions with the same concentration (24% wt/wt): (1) sucrose, (2) glucose, (3) fructose, and (4) a 1:1:1 mixture of these three solutions, as well as a control of pure water. The experimental design involved three replicates per treatment assigned to three different ?blocks? of five feeders each, during eight periods of seven days each. We scored the number of Green-backed Firecrown Hummingbirds feeding on each feeder, the number of consumptions made by each individual, and the amount of sugar (g) consumed per sampling period. Greenbacked Firecrown Hummingbirds clearly discriminated against pure water, favoring sugar solutions; of the latter, they preferred sucrose over glucose and fructose.The mixed-sugar solution showed intermediate preference values. Neither sex nor temperature affected sugar preferences. Sugar preferences by the Green-backed Firecrown Hummingbird could influence the nectar composition of the flowers it pollinates through differential selection. Received 14 September 2006, accepted 25 February 2007.Received 14 September 2006, accepted 25 February 2007. Key words: environmental temperature, Green-backed Firecrown Hummingbird, Sephanoides sephaniodes, sex, sugar preferences,Sephanoides sephaniodes, sex, sugar preferences,