Meeting Abstract
82.3 Friday, Jan. 7 Comparing elastic energy structures in mantis shrimp using finite element analysis ROSARIO, M.V.*; PATEK, S.N.; DUMONT, E.R.; Univ. of Massachusetts, Amherst; Univ. of Massachusetts, Amherst; Univ. of Massachusetts, Amherst mrosario@bio.umass.edu
Extremely fast movements that cannot be accounted for by muscle alone require stored elastic energy. However little is known about variation in the location and distribution of this elastic energy in springs within and among lineages. The mantis shrimp (Crustacea: Stomatopoda) raptorial appendage is a highly specialized structure with spring components, but the impact of morphology on strain energy and elastic energy distribution has not been explored. To measure and compare spring mechanics and strain energy localization, we combined materials testing and finite element analysis to characterize the exoskeletal spring in mantis shrimp. We also introduce the strain energy index of delocalization to quantify the spatial distribution of elastic energy within the entire structure during deformation. Springs from two species of mantis shrimp, representing the prey capture strategies of pounding with tough hammers and stabbing with sharp spears, were measured in a materials testing machine. The spring of Gonodactylus smithii, which is representative of the smashing prey capture strategy, produced an average of 29.69 N (sd=7.59, n= 14) of force when compressed while Lysiosquillina maculata’s spring produced an average of 34.98 N (sd=11.01, n=5).We loaded finite element models of the springs with these forces and found different distributions and magnitudes of strain energy in G. smithii and L. maculata. After scaling the results to remove the effects of size, G. smithii yielded a smaller strain energy value (6.93E-3 J ) than L. maculata (1.30E-2 J) as well as a strain energy index of delocalization (3E-4) that was 5 times smaller than that of L. maculata (1.5E-3). These results may provide insight into the relationship between prey capture strategy and different morphological configurations of elastic energy building blocks.
