SICB Division of Comparative Physiology and Biochemistry (DCPB)

Researchers Database Entry

Kenneth Welch

Hummingbirds hover using sugar
Ken Welch is an Associate Professor of Comparative Vertebrate Physiology at the University of Toronto Scarborough. The Welch lab is broadly interested in animal energetics and, in particular, how diversity in dietary ecology and locomotor behavior and physiology shape diversity in metabolism and strategies for maintaining energy homeostasis. We employ a range of techniques in both the lab and the field, from genetic and molecular approaches to respirometry and stable isotopic tracer techniques to both unravel mechanism and to understand organismal function within an environmental context. The Welch lab has published on everything from the energetic cost of mounting responses to immune challenges in bats (Otálora-Ardila et al., 2017, 2016) to the cost of digestion as it relates to diet (LaBonte et al., 2011; Welch et al., 2015). We have also examined how the costs of hovering change as air density and temperature vary (Groom et al., 2017; Welch and Suarez, 2008), and how hummingbirds modulate wingbeat kinematics to alter power output in response to such variation in abiotic factors (Altshuler et al., 2010; Mahalingam and Welch, 2013). We have also examined how morphology and flight performance vary among elevational gradients and across species and with size to identify broader evolutionary patterns (Groom et al., 2018; Skandalis et al., 2017). We have pioneered the use of breath stable isotopic (BSI) tracers in combination with respirometry (McCue and Welch, 2016; Welch, 2011; Welch et al., 2016) to show that hummingbirds and nectar bats can each fuel up to 100% of energetically expensive hovering flight with either the glucose or fructose in their nectar (Chen and Welch, 2014; Welch Jr. et al., 2006; Welch et al., 2008; Welch and Suarez, 2007). These feats are unprecedented among vertebrates and reflect numerous adaptations in digestive, cardiovascular, and metabolic physiology that promote some of the fastest rates of sugar transport and oxidation known (Welch and Chen, 2014; Welch and Suarez, 2007).



Altshuler, D.L., Welch, K.C., Cho, B.H., Welch, D.B., Lin, A.F., Dickson, W.B., Dickinson, M.H., 2010. Neuromuscular control of wingbeat kinematics in Anna's hummingbirds (Calypte anna). Journal of Experimental Biology 213, 2507-2514. https://doi.org/10.1242/jeb.043497

Chen, C.C.W., Welch, K.C., 2014. Hummingbirds can fuel expensive hovering flight completely with either exogenous glucose or fructose. Functional Ecology 28, 589-600. https://doi.org/10.1111/1365-2435.12202

Groom, D.J.E., Toledo, M.C.B., Powers, D.R., Tobalske, B.W., Welch, K.C., 2018. Integrating morphology and kinematics in the scaling of hummingbird hovering metabolic rate and efficiency. Proc. R. Soc. B 285, 20172011. https://doi.org/10.1098/rspb.2017.2011

Groom, D.J.E., Toledo, M.C.B., Welch, K.C., 2017. Wingbeat kinematics and energetics during weightlifting in hovering hummingbirds across an elevational gradient. J Comp Physiol B 187, 165-182. https://doi.org/10.1007/s00360-016-1016-y

LaBonte, J.P., Welch, K.C., Suarez, R.K., 2011. Digestive performance in neonatal Southern Pacific Rattlesnakes (Crotalus oreganus helleri). Can. J. Zool. 89, 705-713. https://doi.org/10.1139/z11-034

Mahalingam, S., Welch, K.C., 2013. Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird (Archilochus colubris). Journal of Experimental Biology jeb.089383. https://doi.org/10.1242/jeb.089383

McCue, M.D., Welch, K.C., 2016. 13C-Breath testing in animals: theory, applications, and future directions. J Comp Physiol B 186, 265-285. https://doi.org/10.1007/s00360-015-0950-4

Otálora-Ardila, A., Herrera M., L.G., Flores-Martínez, J.J., Welch, K.C., 2017. The effect of short-term food restriction on the metabolic cost of the acute phase response in the fish-eating Myotis (Myotis vivesi). Mammalian Biology 82, 41-47. https://doi.org/10.1016/j.mambio.2016.11.002

Otálora-Ardila, A., M, L.G.H., Flores-Martínez, J.J., Jr, K.C.W., 2016. Metabolic Cost of the Activation of Immune Response in the Fish-Eating Myotis (Myotis vivesi): The Effects of Inflammation and the Acute Phase Response. PLOS ONE 11, e0164938. https://doi.org/10.1371/journal.pone.0164938

Skandalis, D.A., Segre, P.S., Bahlman, J.W., Groom, D.J.E., Jr, K.C.W., Witt, C.C., McGuire, J.A., Dudley, R., Lentink, D., Altshuler, D.L., 2017. The biomechanical origin of extreme wing allometry in hummingbirds. Nature Communications 8, 1047. https://doi.org/10.1038/s41467-017-01223-x

Welch Jr., K.C., Bakken, B.H., Martínez del Rio, C., Suarez, R.K., 2006. Hummingbirds Fuel Hovering Flight with Newly Ingested Sugar. Physiological and Biochemical Zoology 79, 1082-1087. https://doi.org/10.1086/507665

Welch, K.C., 2011. The power of feeder-mask respirometry as a method for examining hummingbird energetics. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, The challenge of measuring energy expenditure: current field and laboratory methods 158, 276-286. https://doi.org/10.1016/j.cbpa.2010.07.014

Welch, K.C., Chen, C.C.W., 2014. Sugar flux through the flight muscles of hovering vertebrate nectarivores: a review. J Comp Physiol B 184, 945-959. https://doi.org/10.1007/s00360-014-0843-y

Welch, K.C., M, L.G.H., Suarez, R.K., 2008. Dietary sugar as a direct fuel for flight in the nectarivorous bat Glossophaga soricina. Journal of Experimental Biology 211, 310-316. https://doi.org/10.1242/jeb.012252

Welch, K.C., Otálora-Ardila, A., M, L.G.H., Flores-Martínez, J.J., 2015. The cost of digestion in the fish-eating myotis (Myotis vivesi). Journal of Experimental Biology 218, 1180-1187. https://doi.org/10.1242/jeb.115964

Welch, K.C., Péronnet, F., Hatch, K.A., Voigt, C.C., McCue, M.D., 2016. Carbon stable-isotope tracking in breath for comparative studies of fuel use. Annals of the New York Academy of Sciences 1365, 15-32. https://doi.org/10.1111/nyas.12737

Welch, K.C., Suarez, R.K., 2007. Oxidation rate and turnover of ingested sugar in hovering Anna's (Calypte anna) and rufous (Selasphorus rufus) hummingbirds. Journal of Experimental Biology 210, 2154-2162. https://doi.org/10.1242/jeb.005363

Welch, Kenneth C., Suarez, R.K., 2008. Altitude and temperature effects on the energetic cost of hover-feeding in migratory rufous hummingbirds, Selasphorus rufus. Can. J. Zool. 86, 161-169. https://doi.org/10.1139/Z07-127