Hindlimb asymmetry reduces escape performance in the lizard Psammodromus algirus

Area of Science:

• * Zoology and biomechanics, focusing on reptilian locomotion.
• * Exploration of morphological asymmetry in animal performance.

Background:

• * Limb asymmetry's potential to affect stability and locomotor efficiency is recognized.
• * The specific impact of limb asymmetry on terrestrial locomotion, particularly in lizards, remains understudied.
• * Fluctuating asymmetry (FA) is a measure of developmental instability.

Purpose of the Study:

• * To investigate the relationship between hindlimb morphology, fluctuating asymmetry, and escape performance in the lizard Psammodromus algirus.
• * To determine if femur or crus length asymmetry affects high-speed terrestrial locomotion.
• * To assess the ecological relevance of reduced performance due to asymmetry.

Main Methods:

• * Measurement of femur and crus lengths and their fluctuating asymmetry in Psammodromus algirus.
• * Analysis of escape performance, including overall escape speeds.
• * Statistical correlation between morphological asymmetry, body size, limb size, and escape performance metrics.

Main Results:

• * Femur length was shorter than crus length, with greater fluctuating asymmetry in femur length.
• * Neither body size nor limb length correlated with fluctuating asymmetry.
• * Femur-length fluctuating asymmetry significantly reduced escape speeds, while crus-length asymmetry did not.
• * Body and limb size were not directly related to escape performance variables.

Conclusions:

• * Femur-length fluctuating asymmetry negatively impacts the escape performance of Psammodromus algirus.
• * Asymmetry in crus length does not appear to affect escape speed in this species.
• * Further research is needed to understand the mechanisms of compensation for locomotor costs associated with asymmetry.