Next Article in Journal
Docosahexaenoic Acid Inhibits Cerulein-Induced Acute Pancreatitis in Rats
Previous Article in Journal
Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) Cohort Study
Previous Article in Special Issue
Sugars, Sweet Taste Receptors, and Brain Responses
Open AccessReview

Sugar Metabolism in Hummingbirds and Nectar Bats

Department of Zoology, University of British Columbia, #4200-6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
Department of Biological Sciences, University of Toronto, 1265 Military Trail, Scarborough, ON M1C 1A4, Canada
Author to whom correspondence should be addressed.
Nutrients 2017, 9(7), 743;
Received: 22 April 2017 / Revised: 3 July 2017 / Accepted: 4 July 2017 / Published: 12 July 2017
Hummingbirds and nectar bats coevolved with the plants they visit to feed on floral nectars rich in sugars. The extremely high metabolic costs imposed by small size and hovering flight in combination with reliance upon sugars as their main source of dietary calories resulted in convergent evolution of a suite of structural and functional traits. These allow high rates of aerobic energy metabolism in the flight muscles, fueled almost entirely by the oxidation of dietary sugars, during flight. High intestinal sucrase activities enable high rates of sucrose hydrolysis. Intestinal absorption of glucose and fructose occurs mainly through a paracellular pathway. In the fasted state, energy metabolism during flight relies on the oxidation of fat synthesized from previously-ingested sugar. During repeated bouts of hover-feeding, the enhanced digestive capacities, in combination with high capacities for sugar transport and oxidation in the flight muscles, allow the operation of the “sugar oxidation cascade”, the pathway by which dietary sugars are directly oxidized by flight muscles during exercise. It is suggested that the potentially harmful effects of nectar diets are prevented by locomotory exercise, just as in human hunter-gatherers who consume large quantities of honey. View Full-Text
Keywords: sugar; glucose transport; hexokinase; metabolism; muscle; energetics; evolution; foraging behavior sugar; glucose transport; hexokinase; metabolism; muscle; energetics; evolution; foraging behavior
Show Figures

Figure 1

MDPI and ACS Style

Suarez, R.K.; Welch, K.C. Sugar Metabolism in Hummingbirds and Nectar Bats. Nutrients 2017, 9, 743.

AMA Style

Suarez RK, Welch KC. Sugar Metabolism in Hummingbirds and Nectar Bats. Nutrients. 2017; 9(7):743.

Chicago/Turabian Style

Suarez, Raul K.; Welch, Kenneth C. 2017. "Sugar Metabolism in Hummingbirds and Nectar Bats" Nutrients 9, no. 7: 743.

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Search more from Scilit
Back to TopTop