Clade-wide variation in bite-force performance is determined primarily by size, not ecology

Area of Science:

• Evolutionary Biology
• Comparative Physiology
• Herpetology

Background:

• Performance traits, crucial for organismal fitness, often show variation across species.
• Understanding the drivers of this variation requires clade-wide analyses, which are often lacking.
• Bite-force is a key performance trait influencing diverse life history aspects in animals.

Purpose of the Study:

• To investigate the phylogenetic relationships between body size, head dimensions, and bite-force in lizards and tuatara (lepidosaurs).
• To test predictions regarding the influence of tooth attachment, diet, and habit on bite-force, controlling for body size.

Main Methods:

• A clade-wide phylogenetic comparative approach was employed.
• The largest bite-force dataset to date for any taxonomic group was utilized.
• Statistical analyses examined correlations between size, morphology, and bite-force across lepidosaurs.

Main Results:

• Bite-force demonstrated a strong positive correlation with both body and head size across the studied lepidosaur species.
• Larger species exhibited significantly greater bite-forces, supporting one key prediction.
• Contrary to predictions, acrodont tooth attachment, herbivorous diets, and non-burrowing habits showed little predictive power for bite-force once size was accounted for.

Conclusions:

• Body and head size are the primary determinants of bite-force variation in lizards and tuatara.
• The apparent link between diet (herbivory) and bite-force is an indirect consequence of larger body size in herbivorous species.
• Future research should focus on expanding sampling to further elucidate evolutionary patterns of performance traits.