Analysis of bone structure in PEROMYSCUS: Effects of burrowing behavior

Area of Science:

• Comparative anatomy
• Functional morphology
• Biomechanics

Background:

• Burrowing is a complex behavior involving significant physical exertion.
• Bone structure is known to adapt to mechanical loads (mechanoadaptation).
• Peromyscus polionotus are known burrowers, while Peromyscus eremicus are not.

Purpose of the Study:

• To investigate the effects of burrowing behavior on appendicular bone structure in two Peromyscus species.
• To compare bone adaptations between a burrowing species (P. polionotus) and a non-burrowing species (P. eremicus).
• To examine developmental plasticity by comparing wild and lab-reared P. polionotus.

Main Methods:

• Micro-computed tomography (micro-CT) scanning of appendicular bones from museum specimens and lab-reared mice.
• Quantification of cortical bone properties (e.g., moment of area).
• Quantification of trabecular bone properties (e.g., thickness, spacing).

Main Results:

• Wild P. polionotus exhibited greater ulnar and tibial cortical bone resistance to bending compared to lab-reared individuals.
• Wild P. polionotus showed enhanced tibial structural properties (normalized second moment of area, cross-sectional area) relative to P. eremicus.
• Tibial and femoral trabecular bone in wild P. polionotus displayed reduced thickness and spacing, indicative of adaptation to high digging loads.

Conclusions:

• Burrowing behavior in Peromyscus induces significant adaptations in appendicular bone structure.
• These findings support the concept of mechanoadaptation in response to behavioral demands.
• The study provides a foundation for exploring the evolutionary and developmental basis of bone adaptation in rodents.