Protein composition of cobweb spiders gumfoot glue droplets

Orb weavers place aggregate glue on a stretchy capture spiral, whereas cobweb weavers add it to the ends of strong, stiff fibers, called gumfoot lines. We describe the quantitative proteomics of the aggregate glues of two cobweb weaving species, the Western black widow, Latrodectus hesperus, and the common house spider, Parasteatoda tepidariorum. For each species respectively, we identified 48 and 33 proteins that were significantly more abundant in the portion of the gumfoot line with glue than in its fibers. These proteins were highly enriched for glycosylation and phosphorylation relative to proteins found in silk fibers. Most enriched proteins were of anterior aggregate gland origin, supporting the hypothesis that cobweb weavers’ posterior aggregate glue is specialized for another function..