Paper wasps really recognise each other's faces.

Most spiders are content to sit and wait for unsuspecting victims to blunder into their silken traps, but webs are only ever as good as the structures that secure them to the surfaces that support them. ‘This [attachment] is done with a special type of silk, called piriform’, says Jonas Wolff, from Macquarie University, Australia, adding that most spiders only produce this silk when they need to securely anchor a structural thread. However, when Wolff and Milan Rezác ̌, from the Czech University of Life Sciences, realised that the piriform silk-producing glands of ground spiders (Gnaphosidae) were different from those of other species – they had fewer and the glands were significantly larger than those of webspinning spiders – the colleagues were intrigued. ‘Why should a lineage of spider deviate from a pattern that is so widespread and hence a long-term success story?’, wondered Wolff. That, coupled with the ground spiders’ novel hunting strategy – they actively ambush prey, snaring them with piriform silk, and even pick fights with insects and arachnids that are larger than themselves – led Wolff, Rezáč and Stanislav Gorb, from the University of Kiel, Germany, to find out more about the ground spider’s extraordinary silk and the glands that produce it.