Effects of Sugar Composition and Concentration on Food Selection by Saussure's Long-nosed Bat (Leptonycteris curasoae) and the Long-tongued Bat (Glossophaga soricina)

Rodríguez-Peña, Nelly; Stoner, Kathryn E.; Schondube, Jorge E.; Ayala-Berdon, Jorge; Flores-Ortíz, César Mateo; Rio, Carlos Martı́nez del

doi:10.1644/06-mamm-a-353r1.1

Cited by 29 publications

(20 citation statements)

References 28 publications

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“…As food items, insects have lower water content (per dry mass or energy) than fruit, blood, and nectar (Morton 1973;Breidenstein 1982;Studier and Sevick 1992;National Research Council 2003;Rodríguez-Peña et al 2007). Furthermore, we predicted that water absorption would be highly correlated with arabinose clearance across species (arabinose is a paracellularly absorbed carbohydrate), based on the hypothesis that paracellular absorption is driven primarily by solvent drag (Pappenheimer and Reiss 1987).…”

Section: Introductionmentioning

confidence: 99%

Intestinal Water Absorption Varies with Expected Dietary Water Load among Bats but Does Not Drive Paracellular Nutrient Absorption

Price¹,

Brun²,

Gontero-Fourcade³

et al. 2015

Physiological and Biochemical Zoology

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Rapid absorption and elimination of dietary water should be particularly important to flying species and were predicted to vary with the water content of the natural diet. Additionally, high water absorption capacity was predicted to be associated with high paracellular nutrient absorption due to solvent drag. We compared the water absorption rates of sanguivorous, nectarivorous, frugivorous, and insectivorous bats in intestinal luminal perfusions. High water absorption rates were associated with high expected dietary water load but were not highly correlated with previously measured rates of (paracellular) arabinose clearance. In conjunction with these tests, we measured water absorption and the paracellular absorption of nutrients in the intestine and stomach of vampire bats using luminal perfusions to test the hypothesis that the unique elongated vampire stomach is a critical site of water absorption. Vampire bats' gastric water absorption was high compared to mice but not compared to their intestines. We therefore conclude that (1) dietary water content has influenced the evolution of intestinal water absorption capacity in bats, (2) solvent drag is not the only driver of paracellular nutrient absorption, and (3) the vampire stomach is a capable but not critical location for water absorption.

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Section: Introductionmentioning

confidence: 99%

Intestinal Water Absorption Varies with Expected Dietary Water Load among Bats but Does Not Drive Paracellular Nutrient Absorption

Price¹,

Brun²,

Gontero-Fourcade³

et al. 2015

Physiological and Biochemical Zoology

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“…Diverse groups of nectar-feeding animals such as bees [24]–[26], birds [27]–[29] and bats [23], [30], [31] show a general pattern of preference for sweeter sugar solutions and more precise discrimination at low concentrations. (Discrimination of nectar volume rewards also follows this pattern, so that choice proportions in 2AFC tests can be fitted against the relative intensity of the stimuli [22], [32], [33].)…”

Section: Introductionmentioning

confidence: 99%

Weber’s Law, the Magnitude Effect and Discrimination of Sugar Concentrations in Nectar-Feeding Animals

2013

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Weber’s law quantifies the perception of difference between stimuli. For instance, it can explain why we are less likely to detect the removal of three nuts from a bowl if the bowl is full than if it is nearly empty. This is an example of the magnitude effect – the phenomenon that the subjective perception of a linear difference between a pair of stimuli progressively diminishes when the average magnitude of the stimuli increases. Although discrimination performances of both human and animal subjects in various sensory modalities exhibit the magnitude effect, results sometimes systematically deviate from the quantitative predictions based on Weber’s law. An attempt to reformulate the law to better fit data from acoustic discrimination tasks has been dubbed the “near-miss to Weber’s law”. Here, we tested the gustatory discrimination performance of nectar-feeding bats (Glossophaga soricina), in order to investigate whether the original version of Weber’s law accurately predicts choice behavior in a two-alternative forced choice task. As expected, bats either preferred the sweeter of the two options or showed no preference. In 4 out of 6 bats the near-miss to Weber’s law provided a better fit and Weber’s law underestimated the magnitude effect. In order to test the generality of this observation in nectar-feeders, we reviewed previously published data on bats, hummingbirds, honeybees, and bumblebees. In all groups of animals the near-miss to Weber’s law provided better fits than Weber’s law. Furthermore, whereas the magnitude effect was stronger than predicted by Weber’s law in vertebrates, it was weaker than predicted in insects. Thus nectar-feeding vertebrates and insects seem to differ in how their choice behavior changes as sugar concentration is increased. We discuss the ecological and evolutionary implications of the observed patterns of sugar concentration discrimination.

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“…However, the nectar bats that we recently studied do not discriminate between solutions of sucrose and glucose + fructose of equal energy content (Rodriguez-Pena et al, 2007). Glossophaga soricina does not migrate, unlike some other nectarivorous bat species (Fleming et al, 1993;Morales-Garza et al, 2007), and does not accumulate much body fat (McNab, 1976).…”

Section: Brief History and Ecological Contextmentioning

confidence: 89%

The sugar oxidation cascade: aerial refueling in hummingbirds and nectar bats

Suarez

Welch

2011

Journal of Experimental Biology

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SummaryMost hummingbirds and some species of nectar bats hover while feeding on floral nectar. While doing so, they achieve some of the highest mass-specific V O2 values among vertebrates. This is made possible by enhanced functional capacities of various elements of the 'O 2 transport cascade', the pathway of O 2 from the external environment to muscle mitochondria. Fasted hummingbirds and nectar bats fly with respiratory quotients (RQs; V CO2 /V O2 ) of ~0.7, indicating that fat fuels flight in the fasted state. During repeated hover-feeding on dietary sugar, RQ values progressively climb to ~1.0, indicating a shift from fat to carbohydrate oxidation. Stable carbon isotope experiments reveal that recently ingested sugar directly fuels ~80 and 95% of energy metabolism in hover-feeding nectar bats and hummingbirds, respectively. We name the pathway of carbon flux from flowers, through digestive and cardiovascular systems, muscle membranes and into mitochondria the 'sugar oxidation cascade'. O 2 and sugar oxidation cascades operate in parallel and converge in muscle mitochondria. Foraging behavior that favours the oxidation of dietary sugar avoids the inefficiency of synthesizing fat from sugar and breaking down fat to fuel foraging. Sugar oxidation yields a higher P/O ratio (ATP made per O atom consumed) than fat oxidation, thus requiring lower hovering V O2 per unit mass. We propose that dietary sugar is a premium fuel for flight in nectarivorous, flying animals.

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Effects of Sugar Composition and Concentration on Food Selection by Saussure's Long-nosed Bat (Leptonycteris curasoae) and the Long-tongued Bat (Glossophaga soricina)

Cited by 29 publications

References 28 publications

Intestinal Water Absorption Varies with Expected Dietary Water Load among Bats but Does Not Drive Paracellular Nutrient Absorption

Intestinal Water Absorption Varies with Expected Dietary Water Load among Bats but Does Not Drive Paracellular Nutrient Absorption

Weber’s Law, the Magnitude Effect and Discrimination of Sugar Concentrations in Nectar-Feeding Animals

The sugar oxidation cascade: aerial refueling in hummingbirds and nectar bats

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