Title: What Forces Are Responsible for the Stickiness of Spider Cribellar Threads?
Author: Brent D. Opell
Abstract: The surface of spider cribellar prey capture thread is formed of thousands of fine silk fibrils. The stickiness of this thread is often attributed to the ability of these fibrils to catch on irregular surfaces. However, 14-month-old cribellar threads of Hyptiotes cavatus (Uloboridae) were significantly less sticky than freshly spun threads. Slight changes in cribellar thread dimensions failed to fully explain this reduced stickiness, demonstrating that an auxiliary force contributes to the stickiness of cribellar threads. Because this force does not appear to rely on the snagging of fibrils, it may enhance the ability of cribellar threads to hold prey with smooth surfaces.