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Cambridge University Science Magazine

Spider silk has many amazing properties — it’s so strong and elastic that it’s used in anti-explosive clothing for soldiers in minefields and in space net designs. The webs themselves are uniquely able to simultaneously serve as a home and prey capture tool. Studies show spider web designs change with different drug exposure. Each spider leg has a separate building purpose, and different web areas serve different functions. But one structure still eludes scientists to this day: the stabilimentum.

Stabilimenta are highly UV reflective structures found in multiple spider species’ webs. They are silk threads arranged in a zig-zag fashion as a line, cross, circle, or spiral within the web. These beautiful structures have been studied for over a century but, still, nobody knows what they are for. Some suggest they are for defending against wasps, attracting prey, preventing bird collisions with webs, and even providing camouflage. Despite extensive research using fake stabilimenta in webs to see how many flies get caught, or how many birds collide with them, their function remains elusive. Spiders expend much energy on stabilimenta production — it takes lots of silk to make a stabilimentum — so they must have a function. What that function actually is, however, remains a mystery. 

Laura Chilver