The influence of the auxiliary spiral on the capture spiral in Araneus diadematus Clerck (Araneidae)

Summary T he relationship between direction of coiling and shape of the auxiliary spiral and that of the capture spiral in orb webs of Araneus diadematus Clerck (Araneidae) was investigated. In m ost w ebs, the two spirals had the same d irection of coiling a nd a similar shape, indicating that the auxiliary spiral serves as a guide during c onstruction of the capture spiral. Possible causes and mechanisms are discussed.