Meeting Abstract

P2-151   -   Testing the impact of autotomy on locomotion in the insect Leptoglossus phyllopus Greenway, EV*; Beck, HK; Labonte, D; Miller, CW; University of Florida; Imperial College London; Imperial College London; University of Florida ginny.greenway@gmail.com

Autotomy, the self-induced loss of a body part, is a commonly deployed behavior used by animals to escape the grasp of a predator. The instant survival benefit from dropping a limb likely comes with a substantial long term fitness penalty, especially in species which cannot regenerate their lost body parts. Whilst lizards and crabs can regrow their tails and claws, insects such as the coreid Leptoglosuss phyllopus must instead survive without their autotomized limb. Over 21% of wild adult L. phyllopus are found missing a leg, thus we anticipate evolutionary selection for locomotory compensation. Here we ask how autotomy impacts locomotion by assessing gait parameters before and after limb loss in fourth instar juveniles. We filmed L. phyllopus nymphs walking freely across a horizontal surface using a custom camera setup which captured their movement from 5 different angles. We then re-recorded them 24hrs later after experimentally inducing them to detach a hind leg. Finally, we reconstructed the 3D coordinates of 39 key locations on their body throughout the gait cycles. Pairwise comparisons between individuals pre- and post-autotomy revealed compensatory changes in response to limb loss; the range of motion of the remaining fore- and mid-legs on the side on which autotomy occurred shifted backward, and the stride frequency decreased. Hind limb loss nevertheless resulted in a high incidence of abdomen ground contact, indicating that the adjustments to the gait patterns were insufficient to fully compensate for the reduction in dynamic stability resulting from autotomy. Dragging of the abdomen in particular likely increases the energetic cost of movement and risk of cuticle damage, which will be addressed in future work. Given the tens of thousands of species across taxa that autotomize, it is crucial that we better understand the fitness consequences of autotomy as well as adaptations which have evolved to limit the negative impacts of this costly behaviour.