Did you know that spiders doodle on their webs, adding splashes of decoration such as spirals, crosses and circles ? Now researchers think they know why. Only certain types of spiders are doodlers - ones that sit in the middle of their web as they hunt by day. Todd Blackridge from the University of California took webs from the American Orb-weaving spider and removed the doodles from half the webs. He then let the spiders loose on the webs and watched what happened. The webs with extra patterns didn't catch much prey - on average 30% less. But the spiders sitting on the nests with doodles were far less likely to be eaten by predators like wasps. So the doodles are a payoff between eating and being eaten. Blackridge doesn't know how the doodles work, but thinks they could be intended to distract or confuse the predators, leading them to ignore the spider.