The role of dietary fatty acids in the evolution of spontaneous and facultative hibernation patterns in prairie dogs |
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Authors: | H J Harlow C L Frank |
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Institution: | (1) Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA e-mail: hharlow@uwyo.edu Tel.: +1-307-7663321; Fax: +1-307-7665625, US;(2) The Louis Calder Center, Biological Station and Department of Biological Sciences, Fordham University, P.O. Box K, Armonk, NY 10504, USA, US |
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Abstract: | The white-tailed prairie dog is a spontaneous hibernator which commences deep torpor bouts during early fall while the black-tailed
prairie dog is a facultative hibernator that will only enter shallow torpor when stressed by cold and food deprivation. Plant
oils rich in polyunsaturated fatty acids (PUFAs) enhance the duration and depth of mammalian torpor. Thus, we tested the hypothesis
that black-tailed prairie dogs sampled in the field have less PUFAs in their diets and that the enhancement of torpor bouts
by this species on a diet higher in PUFA is less profound than that by white-tailed prairie dogs. Individuals of both species
fed a high PUFA diet: (1) entered torpor earlier, (2) had lower torpor body temperatures and (3) had longer bouts of torpor,
compared to those on a low PUFA diet. However, the magnitude of this change was similar for both species. Additionally, the
PUFA compositions of white adipose tissue (WAT) samples taken from individuals in the field were identical, indicating that
diet PUFA contents for these two species were also equivalent. Therefore, while high PUFA diets can enhance hibernation by
these species, it does not appear to explain the differences between spontaneous and facultative strategies. The rate of lipid
peroxidation during torpor, however, was significantly higher in the WAT from white-tailed prairie dogs. Ancestral prairie
dog species are spontaneous hibernators. Natural selection may have favored shallow, facultative hibernation with lower lipid
peroxidation rates in the black-tailed prairie dogs as they radiated from the Rocky Mountains into the Great Plains.
Accepted: 12 September 2000 |
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Keywords: | Prairie dogs Hibernation Fatty acid saturation Lipid peroxides |
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