FUNCtional implications of ontogeny

INTRODUCTION:

For precocious vertebrates, the need for locomotor activity begins soon after hatching or birth. Juveniles may occupy the same habitat as their adult counterparts and therefore, compete for the same resources. Consequently, juveniles must be able to perform multiple locomotor tasks at a reasonably similar level, despite their smaller size. Most animals grow allometrically, where their body proportions change as they get larger. These changes potentially impact their performance in various locomotor tasks. Scaling models have been proposed to predict the relationships between body size and performance variables, where velocity increases with a slope of one, increasing at the same rate as linear body dimensions. While these models do apply in some cases under specific conditions, many empirical studies have shown that the relationship between length and velocity does not always follow the predicted trajectory and slopes may vary between multiple modes of locomotion.

This study aims to address (1) if running, jumping, swimming, and climbing performance in brown basilisks, Basiliscus vittatus, follow scaling models and (2) whether the scaling of the underlying locomotor kinematics and phenotypic traits for each mode of locomotion scale in the same way as performance. Results show that climbing maximum velocity scales isometrically with body length but running and swimming velocities scale negatively allometrically. Jumping maximum acceleration has no relationship with body length. In general, the relative lengths of the tail, head, thigh, forearm, and most muscle functional groups had the strongest relationships to performance within all modes of locomotion.

THE MAIN QUESTION:

How will performance in multiple modes of locomotion change throughout ontogeny?