QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online December 10, 2003
Journal of Experimental Biology 207, 295-305 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00760

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rezende, E. L. Articles by Hammond, K. A. Search for Related Content PubMed PubMed Citation Articles by Rezende, E. L. Articles by Hammond, K. A.

Cold-acclimation in Peromyscus: temporal effects and individual variation in maximum metabolism and ventilatory traits

Enrico L. Rezende^*, Mark A. Chappell and Kimberly A. Hammond

Department of Biology, University of California, Riverside, California 92521, USA

View larger version (25K): [in a new window]   Fig. 1. O2max values throughout acclimation in P. maniculatus submitted to cold-acclimation (closed symbols) and control individuals (open symbols). The broken vertical line indicates the beginning of the cold-acclimation. Values are means ± S.E.M., and different symbols are used for the three different subgroups measured in each treatment (see Materials and methods for details and N values).

View larger version (21K): [in a new window]   Fig. 2. Body mass values throughout acclimation for control (open symbols) and cold-acclimated individuals (closed symbols). Circles, females; triangles, males. The broken vertical line indicates the beginning of the cold-acclimation. Values are means ± S.E.M.

View larger version (32K): [in a new window]   Fig. 3. Changes in respiratory frequency (f), tidal volume (VT), minute volume (VMIN) and oxygen extraction (OEE) throughout acclimation in control (open symbols) and cold-acclimated individuals (closed symbols). Circles, females; triangles, males. The broken vertical line indicates the beginning of the cold-acclimation. Values are means ± S.E.M.

View larger version (19K): [in a new window]   Fig. 4. Ratio of values in cold-acclimated/control animals for maximum metabolic rate (O2max) respiratory frequency (f), tidal volume (VT), minute volume (VMIN) and oxygen extraction (OEE) throughout acclimation. Ratios were calculated after taking body mass into account (values were expressed on a per gram basis). The straight horizontal line represents a 1:1 ratio and the broken vertical line indicates when cold-acclimation began.

View larger version (22K): [in a new window]   Fig. 5. Individual consistency between initial and final body mass (A), O2max (B) and mass-independent O2max (C) in control (left) and cold-acclimated (right) animals. Initial and final values were calculated as the individual mean value from weeks 2+3, and 9+10, respectively (see Materials and methods). The Pearson product-moment coefficient for each correlation is also reported, and its respective probability value.

View larger version (10K): [in a new window]   Fig. 6. Diagram showing how the time-lagged logistic growth curve can be analogous to the temporal course of O2max during acclimation in a negative feedback control system (in this hypothetical case, the animal went from a warm to a cold temperature, as in the present study; see Fig. 1). Nt, population size at time t; r, maximum rate of growth and/or of acclimation; , length of the delay between stimulus and response. O2max `warm' and O2max `cold' (dotted lines) represent the values of O2max at `equilibrium' - i.e. when the animal is actually acclimated to warm and cold conditions. These values are analogous to the initial population size at t=0 (N0) and the carrying capacity of the habitat (K), respectively.