Meeting Abstract
The evolution of viscid aggregate glues is associated with the radiation of orb-weaving spiders. Aggregate glue forms the sticky droplets on prey capture threads and is a composite of viscoelastic glycoproteins and organic salts. While the glycoproteins are the primary adhesive, the salts absorb atmospheric water, thereby plasticizing the threads, and directly solvate the proteins, helping the glycoproteins to spread across surfaces. The high extensibility of the droplets allows them to extend in a “suspension bridge” system that also recruits adhesion across the entire thread’s length. Here, we explore how each of these elements is responds responsive to humidity and results in the capture threads of diverse species of spiders function optimally at different humidities. We argue that the chemical composition of the organic salts is a highly evolvable mechanism that “tunes” orb function to particular microhabitats.
