Meeting Abstract
Modern orb-web spiders use micron sized glue droplets to capture and retain prey. The orb-web spider glue is a unique biological adhesive that gets stickier upto an optimal humidity that varies among species. A combination of bulk glue viscosity and surface bonding contribute to the glue adhesion. However, the mechanism of humidity response of adhesion is poorly understood. Here, we use high-speed imaging and adhesion tests to probe glue adhesion at different humidity’s. For the first time glue viscosity was directly measured from the spreading of the glue droplet during immobilization. Peeling of the glue droplets at different humidity’s show a transition from adhesive failure, at low humidity, to cohesive failure, at high humidity. The adhesion results support the microscopic observations. Hence, significant changes in glue viscosity explains the humidity response of the spider glue adhesion and can help in designing better synthetic adhesives for the high humidity environment.
