Meeting Abstract

48.5  Monday, Jan. 5  Evolution of supercontraction in spider silk BOUTRY, C.**; BLACKLEDGE, T.A.; University of Akron; University of Akron cb54@uakron.edu

Spider silk is a high performance material renowned for its tensile properties. However, silk can also strongly contract when exposed to high humidities (~70%) and shrink by up to 50%, generating high stresses (~50 MPa). Supercontraction poses a challenge for biomimetic applications of silk, therefore its mechanism and function must be understood. Supercontraction is thought to result from silk’s complex protein composition and highly oriented molecular structure. It may allow orb-webs to remain tight under the added weight of raindrops or dew. However, most work on supercontraction has focused solely on orb-weavers. Investigating supercontraction in non orb-weaving spiders, with different silk structure and composition, may shed light on the mechanisms and evolutionary role of this phenomenon. In this study, we measured supercontraction in dragline silk from phylogenetically and ecologically diverse spider taxa. In particular, we found supercontraction in many non-orb weaving spiders. These results suggest that supercontraction may be a relatively ancestral trait within spiders and challenge current hypotheses about its mechanism and function.