Impact of Different Developmental Instars on Locusta migratoria Jumping Performance

Area of Science:

• Biomechanics
• Evolutionary Biology
• Zoology

Background:

• Ontogenetic locomotion, the study of locomotion evolution across developmental stages, is under-researched in invertebrates.
• Locusts (Locusta migratoria) are suitable models for studying ontogenetic locomotion due to their consistent development.
• Jumping performance across different developmental stages (instars) of locusts remains largely unquantified.

Purpose of the Study:

• To investigate the ontogenetic changes in jumping performance of Locusta migratoria.
• To develop a simplified biomechanical model of locust jumping.
• To understand the energetic and geometric factors influencing jumping ability across developmental stages.

Main Methods:

• High-speed cameras recorded the jumping of third instar, fourth instar, and adult Locusta migratoria.
• A simplified biomechanical model was created, representing the locust hind leg's elastic joint as a torsional spring.
• Locomotion and geometrical data were used for an energetic approach to evaluate jump performance via a mathematical model.

Main Results:

• Adult locusts exhibit longer hind legs, higher elastic parameters, and longer takeoff times compared to younger instars.
• These factors contribute to greater velocity and enhanced energy storage/release in adult locusts.
• The observed adaptations in adult locusts compensate for potential decreases in acceleration due to increased body mass.

Conclusions:

• Locust ontogeny leads to significant improvements in jumping mechanics, driven by morphological and elastic adaptations.
• The findings provide valuable data for understanding invertebrate locomotion and inform the design of bioinspired jumping robots.
• This study highlights the importance of considering developmental trajectories in biomechanical research.