Discipline: Ecology Environmental and Earth Sciences
Nina Scott - University of the Virgin Islands
Co-Author(s): Jennifer R.A. Taylor, Scripps Institution of Oceanography, San Diego, California.
Some mantis shrimp species known as ‘smashers’ have specialized hammer-like appendages that yield forces sufficient to break hard-shelled prey. Yet, these powerful appendages do not damage the telsons of conspecifics during ritualized fighting, whereby opponents take turns striking each other on the telson. Smashing mantis shrimp are thought to have evolved a more robust telson in conjunction with ritualized fighting but, little is known about how the telson is adapted for impact resistance. Here we tested the hypothesis that smasher species have a mechanically more robust telson by comparing the telson morphology and material properties of a smasher with a spearer species that has a spear-like appendage and no telson sparring behavior. We removed telsons from the smasher Neogonodactylus bredini (carapace length 12.60 ± 1.05 mm, N =8) and the spearer Squilla empusa (carapace length 20.33 ± 2.73 mm, N=8) to examine the cuticle structure with scanning electron microscopy and the elemental composition with energy dispersive x-ray spectroscopy. The hardness and stiffness of the center carina (telson ridge that receives strikes) were measured using nanoindentation. The carinae of both species are similar in cuticle structure and composition as well as material properties (T-test, Hardness: t= 1.78N=8, P < 0.05; Stiffness t= 1.76, N=8, P < 0.05). This smasher species appears not to have a more mechanically robust telson structure. These findings provide no support for the hypothesis that telson morphology co-evolved with ritualized fighting in mantis shrimp. In the future, we plan to extend this study to more species to determine general patterns. In addition, we will distinguish between telson morphology and material properties and mantis shrimp strike forces determining potential correlation of weapon power and shield robustness.
Funder Acknowledgement(s): National Science Foundation
Faculty Advisor: Jennifer R. A. Taylor, email@example.com
Role: I participated in the Scripps Undergraduate Research Fellowship where I was assigned to Dr. Taylor's Marine Invertebrate Biomechanics lab. There, I picked a research topic and conducted my experiment under the supervision of my P.I..