Forage preferences in two species of prairie dog (Cynomys parvidens and Cynomus ludovicianus): Implications for hibernation and facultative heterothermy

Journal of Zoology
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Abstract

Several laboratory studies have shown that the ingestion of dietary linoleic (18:2 ??6) acid before winter can promote deep and continuous torpor, whereas excess consumption of ??-linolenic acid (18:3 ??3) can interfere with an animal's ability to reach and maintain low body temperatures during torpor. As mammalian heterotherms obtain linoleic and ??-linolenic acid strictly from the diet, diet selection has been proposed as a mechanism that allows hibernators to ingest levels of linoleic and ??-linolenic acid that promote favorable torpor patterns. Here diet, dietary nutrient content and patterns of forage preference of a representative hibernator, the Utah prairie dog Cynomys parvidens, and a facultative heterotherm, the black-tailed prairie dog Cynomys ludovicianus, were examined under natural field conditions. Diets of black-tailed (BTPD) and Utah prairie dogs (UTPD) differed across seasons (BTPD F26,108=9.59, P<0.01; UTPD F38,80=3.25, P<0.01) and elevations (BTPD F26,108=20.15, P<0.01; UTPD F38,80=20.51, P<0.01), and forage preference indices indicate that neither species randomly selected plant species relative to their abundance on colonies in any season. Black-tailed prairie dogs did not consume or avoid consumption of plant species based on levels of total lipids, linoleic acid, ??-linolenic acid or nitrogen. Considering only the plants consumed, black-tailed prairie dogs appeared to prefer plants with low levels of ??-linolenic acid (F1,19=5.81, P=0.03), but there were no detectable relationships between preference and other nutrients. Utah prairie dogs consumed plants higher in ??-linolenic acid (t=1.98, P=0.05) and avoided plants high in linoleic acid (t=-2.02, P=0.04), but consumption-avoidance decisions did not appear to be related to nitrogen or total lipids. Of the plants consumed, Utah prairie dogs again preferred plants high in ??-linolenic acid (F1,17=4.62, P=0.05). Levels of linoleic and ??-linolenic acid were positively correlated in plants consumed by prairie dogs (BTPD Pearson r=0.66, P<0.01; UTPD Pearson r=0.79, P<0.01), reducing the opportunity for independent selection of either lipid. ?? 2006 The Authors.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Forage preferences in two species of prairie dog (Cynomys parvidens and Cynomus ludovicianus): Implications for hibernation and facultative heterothermy
Series title Journal of Zoology
DOI 10.1111/j.1469-7998.2006.00085.x
Volume 269
Issue 2
Year Published 2006
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Zoology
First page 249
Last page 259