Meeting Abstract
Limbed locomotion requires the coordinated movement of limbs to produce maximal performance, but what are the consequences of limb loss on locomotor strategy and efficiency? Quadrupedal animals that lose a limb must alter their kinematic patterns to maintain the ability to locomote. While animals with more limbs should be less severely impacted by the loss of a single limb, their locomotor performance may similarly be enhanced by modulation of kinematic patterns. Do animals always modulate kinematic patterns? Will animals in similar situations converge on a single, optimal answer? To address these questions, we examined the effects of foreleg loss on locomotor performance in the darkling beetle Zophobas morio. We collected data on locomotor performance (distance traveled per limb cycle and locomotor speed). We also used GMM techniques and multivariate analyses to investigate the position and timing of footfalls during stance. Data were collected from beetles under three conditions: (C) control, unaltered beetle; (RA) right after, data collected on the day of limb removal, and (LA) long after, data collected a week following limb removal. While leg loss did not impact the distance that beetles traveled over a full limb cycle, there was a significant decrease in speed between the control treatment and the two experimental treatments. Following leg removal, experimental beetles altered the position and timing of foot placement for the remaining five legs. However, immediately following leg removal (RA), beetles displayed foot placements more similar to control treatments and these patterns diverged more with time (LA). In addition to differences in foot position, we also found that variation in foot position increased with time, presumably as individuals identify different strategies that help to produce more stable locomotion.
