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

First published online May 18, 2006
Journal of Experimental Biology 209, 2103-2113 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02233

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 Google Scholar Google Scholar Articles by White, C. R. Articles by Seymour, R. S. Search for Related Content PubMed PubMed Citation Articles by White, C. R. Articles by Seymour, R. S.

Balancing the competing requirements of saltatorial and fossorial specialisation: burrowing costs in the spinifex hopping mouse, Notomys alexis

Craig R. White^*, Philip G. D. Matthews and Roger S. Seymour

Environmental Biology, School of Earth and Environmental Sciences, The University of Adelaide, Adelaide, SA, Australia 5005

View larger version (11K): [in a new window]   Fig. 1. Effect of ambient temperature on resting rate of oxygen consumption (O2, ml min-1) for a single male hopping mouse, Notomys alexis (body mass=28.1 g). N=21. Below 26.8°C, O2=2.93-0.082Ta; above 26.8°C, O2=0.72.

View larger version (8K): [in a new window]   Fig. 2. Relationship between metabolic rate (O2, ml min-1) and speed (m min-1) for a single male hopping mouse (body mass=31.5 g). The break-point of the regression relating O2 and speed is equal to maximum aerobic speed (Umax, m min-1). At slower speeds, the slope of the line relating O2 and speed is equal to the net O2 cost of transport (ml O2 m-1). Average O2 at speeds greater than Umax is equal to maximum metabolic rate (O2max, ml min-1). N=12. Below 21.8 m min-1, O2=1.80+0.100U, where U is speed; above 21.8 m min-1, O2=3.98.

View larger version (16K): [in a new window]   Fig. 3. Diagrammatic representation of the chamber used for measurement of burrowing O2. The plug functioned both to reduce the airspace in the chamber and to prevent spoil from collecting within the chamber.

View larger version (16K): [in a new window]   Fig. 4. Example trace of a typical burrowing trial (female mouse, 36.1 g, excurrent airflow rate=1.6 l min-1). The mouse was placed in the chamber at the point indicated on the graph. It then explored the chamber and scratched at the soil for 3 min, rested for 1 min and burrowed for 35 min. The washout after the mouse was placed in the chamber suggests an equilibration time of approximately 5 min. FO2, fractional oxygen concentration.

View larger version (15K): [in a new window]   Fig. 5. Relationship between body mass and net cost of pedestrian (filled triangles, NCOTp) and burrowing (filled circles, NCOTb) transport for individual hopping mice, Notomys alexis. Unfilled symbols are mean NCOTb measurements for a variety of burrowing mammals taken from the literature (Vleck, 1979; Du Toit et al., 1985; Lovegrove, 1989; Seymour et al., 1998; Withers et al., 2000). Regression line shows NCOTp for walkers and runners derived from (Full et al., 1990) and incorporates data from mammals, birds, reptiles, amphibians, myriapods, crustaceans and insects.

View larger version (16K): [in a new window]   Fig. 6. Relationship between rate of oxygen consumption during burrowing (O2b) and body mass for fossorial (filled circles) and semi-fossorial (open circles) mammals. Solid line is the phylogenetically correct regression relating O2b to mass for fossorial species (O2b=0.065Mb0.98±0.06, where the mass exponent is mean ± s.e.). Inner dotted lines represent the 95% confidence interval of this regression; outer broken lines represent the 95% prediction interval. Data sources are provided in Table 1.

View larger version (16K): [in a new window]   Fig. 7. Relationship between maximum running speed (MRS) and body mass for fossorial (filled circles) and semi-fossorial (open circles) mammals. Solid line is the phylogenetically correct regression relating MRS to mass for fossorial species (equation: MRS=1.27M 0.21±0.04b, where the mass exponent is mean ± s.e.). Inner dotted lines represent the 95% confidence interval of this regression; outer broken lines represent the 95% prediction interval. Data sources are provided in Materials and methods.

View larger version (14K): [in a new window]   Fig. 8. Correlation between residual contrasts in maximum running speed (MRS) and habitat type for non-fossorial rodents and marsupials. Habitat type was scored according to Garland et al. (Garland et al., 1988): 3=open country, e.g. deserts; 2=terrestrial, but habitat less open than in 3; 1=intermediate between terrestrial and arboreal; 0=arboreal.

View larger version (10K): [in a new window]   Fig. A1. (A) Effect of efficiency of conversion of metabolic energy to mechanical work against gravity and (B) mass of spoil (expressed as % of body mass) carried in each trip to the surface on total burrow construction cost for Notomys alexis. Filled symbol represents spoil mass used in model calculations (4.4% and 25% for conversion efficiency and spoil mass, respectively; total burrow cost=55.5 kJ).