I found this really interesting article about Darwin’s bark spider. These spiders live in Madagascar and can create one of the largest known orb webs. These webs can be close to 3m in diameter with anchor lines spanning up to 25m and are built over a river or small lake. This paper studied the spiders and wanted to see if the webs were specifically designed to capture large prey, even vertebrates. The spiders’ silk is the toughest known spider silk, which implies that it could be possible for the Darwin’s bark spider to catch extremely large prey. However, this study of Darwin’s bark spider found that the largest prey captured was a dragonfly and that most of the animals caught in the webs were small insects.
Image from http://news.nationalgeographic.com/news/2010/09/photogalleries/100917-darwins-bark-spider-new-species-spider-webs-madagascar-science-pictures-strongest/#/huge-spider-webs-crossing-river_26175_600x450.jpg
Gregoric M., Agnarsson I., Blackledge T., and Matjaz K. 2011. Darwin’s bark spider: giant prey in giant orb webs? Journal of Arachnology, v. 39(2) p. 287-295.