The comparative energetics of 'caviomorph' rodents

Area of Science:

• Zoology
• Physiology
• Ecology

Background:

• Caviomorph rodents, a diverse group of New World hystricognaths, exhibit varied metabolic strategies.
• Understanding the factors influencing their basal metabolic rates is crucial for ecological and evolutionary studies.

Purpose of the Study:

• To investigate the key factors affecting basal metabolic rates in caviomorph rodents.
• To explore the relationships between body mass, habitat, diet, and geographic origin with metabolic energetics.

Main Methods:

• Analysis of basal metabolic rates for 11 New World hystricognath species, supplemented with literature data for 19 additional species.
• Statistical modeling to determine the influence of body mass, habitat stratum, diet, and island endemism on basal metabolic rates.
• Correlation analysis between body mass and minimal thermal conductance.

Main Results:

• Log(10) body mass explained 94% of the variation in log(10) basal metabolic rate.
• Residual variation was linked to habitat: arboreal species had lower rates, terrestrial/fossorial species intermediate rates, and aquatic species higher rates.
• Folivorous, arboreal, and small island endemic caviomorphs exhibited significantly lower basal metabolic rates compared to continental species.

Conclusions:

• Basal metabolic rates in caviomorphs are shaped by a complex interplay of factors including body mass, habitat, diet, and island isolation.
• Habitat and diet are significant modifiers of metabolic rates, particularly in arboreal folivores.
• Body mass is the primary determinant of thermal conductance, independent of other ecological factors.