Table of Contents

  1. Introduction
  1. Aims
  2. Methods
  3. Results and Discussion
  1. Conclusions and Future Directions
  2. References

1. Introduction

Eight-legged locomotion is one of the most ancient travelling modes on land. Spiders exhibit a diverse locomotion repertoire, moving at slow and fast speeds, forwards, backwards, sideways, and even jumping and climbing, all at similar speeds and maintaining high locomotor performance (Biancardi et al. 2011). They can voluntarily lose legs when threatened, a phenomenon called autotomy, which has shown to have negative effects on locomotor performance (Wrinn and Uetz 2008). At the costs of autotomy on locomotor performance, a trade-off with survival and other benefits should exist, as autotomy has been maintained in several lineages across evolutionary time. Perhaps one of the additional benefits of autotomy conservation comes from the way they compensate for it by adjusting kinematic patterns and neural control mechanisms. Rhythmic motor behaviors such as walking are controlled by Central Pattern Generators (CPGs), which are centrally located neural circuits capable of generating rhythmic and repetitive outputs even in the absence of sensory feedback (Dickinson 2006; Katz 2016). CPGs evidence behavioral flexibility, which suggests that on spiders, learning from previous autotomized limbs, can play an important role on increasing locomotor performance after subsequent limb autotomizations and regeneration. Therefore, the main goal of the first phase of this project is twofold: 1) determine the effects of limb autotomy on running performance and kinematics and, 2) determine how gait is adjusted after limb autotomy. We hypothesize running performance will decrease after first autotomy. These findings will be determinant for the second phase of the project; gait analyses after leg regeneration and second autotomy, to determine if long-term learning plays an important role in spider gait adaptation.

1.1 What is Autotomy?

  • Voluntary shed of one or more appendages
lizard tail autotomy