Science Reports Spiders’ Orb Web May Have Single, Ancient Origin

The orb web, the classical wheel-shaped net that made Charlotte and countless other spiders famous, is spun by two different groups of spiders. For a long time, scientists debated whether these two groups had evolved this marvel of engineering independently. Now, new evidence reported in the 23 June issue of Science suggests the orb web had a single evolutionary origin and may have been snagging flying insects as early as 136 million years ago.

New genetic evidence from one set of orb-web spinners called the Deinopoidea confirms that the group shares some key silk proteins with its fellow orb weavers the Araneoidea, according to postdoctoral researcher Jessica Garb of the University of California-Riverside and her colleagues. Based on fossil evidence, the ancestor of the two spider groups probably lived at least 136 million years ago, making the orb web an ancient adaptation.

Science is published by AAAS, the nonprofit science society.

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