B.B.C.: '...more than 100 million years ago, in the early Cretaceous period, a major shift in the design of spiders' orb-shaped webs came about.
'Before then, spiders coated the spirals in their webs with puffs of dry adhesive. These dry spirals trapped insects by physically entangling around the tiny hairs known as setae on their bodies. A group of spiders living today, known as deinopoid spiders, still weave webs in this way.
'However, during the early Cretaceous, araneoid orb weaving spiders evolved which weaved a different type of web. These spiders replaced the dry adhesive with wet droplets of glue. These are much stickier.'