RESEARCH ARTICLE

Prey interception drives web invasion and spider size determines successful web takeover in nocturnal orb-web spiders Wenjin Gan1,2, Shengjie Liu3, Xiaodong Yang2, Daiqin Li4, * and Chaoliang Lei1,* A striking feature of web-building spiders is the use of silk to make webs, mainly for prey capture. However, building a web is energetically expensive and increases the risk of predation. To reduce such costs and still have access to abundant prey, someweb-building spiders have evolved web invasion behaviour. In general, no consistent patterns of web invasion have emerged and the factors determining web invasion remain largely unexplored. Here we report web invasion among conspecifics in seven nocturnal species of orb-web spiders, and examined the factors determining the probability of webs that could be invaded and taken over by conspecifics. About 36 % of webs were invaded by conspecifics, and 25 % of invaded webs were taken over by the invaders. Aweb that was built higher and interceptedmore prey wasmore likely to be invaded. Once aweb was invaded, the smaller the size of the resident spider, the more likely its web would be taken over by the invader. This study suggests that web invasion, as a possible way of reducing costs, may be widespread in nocturnal orb-web spiders