The intake responses of three species of leaf-nosed Neotropical bats.
Flower-visiting bats encounter nectars that vary in both sugar composition and concentration. Because in the new world, the nectars of bat-pollinated flowers tend to be dominated by hexoses, we predicted that at equicaloric concentrations, bats would ingest higher volumes of hexoses than sucrose-containing nectars. We investigated the intake response of three species of Neotropical bats, Leptonycteris curasoae, Glossophaga soricina and Artibeus jamaicensis, to sugar solutions of varying concentrations (292, 438, 584, 730, 876, and 1,022 mmol L(-1)) consisting of either sucrose or 1:1 mixtures of glucose and fructose solutions. Bats did not show differences in their intake response to sucrose and 1:1 glucose-fructose solutions, indicating that digestion and absorption in bat intestines are designed under the principle of symmorphosis, in which no step is more limiting than the other. Our results also suggest that, on the basis of energy intake, bats should not prefer hexoses over sucrose. We used a mathematical model that uses the rate of sucrose hydrolysis measured in vitro and the small intestinal volume of bats to predict the rate of nectar intake as a function of sugar concentration. The model was a good predictor of the intake responses of L. curasoae and G. soricina, but not of A. jamaicensis.
Ayala-Berdon
Jorge
J
Centro de Investigaciónes en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Michoacán, México. jayala@oikos.unam.mx
Schondube
Jorge E
JE
Stoner
Kathryn E
KE
Rodriguez-Peña
Nelly
N
Del Río
Carlos Martínez
CM
D000818:Animals; D001069:Appetite Regulation; D002685:Chiroptera / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000378:metabolism*; D019422:Dietary Sucrose / Q000378:metabolism; D004063:Digestion; D004435:Eating; D002149:Energy Intake; D005247:Feeding Behavior; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D007408:Intestinal Absorption; D008800:Mexico; D008954:Models, Biological; D009994:Osmolar Concentration; D014882:Water-Electrolyte Balance
D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D005632:Fructose; D005947:Glucose