Chemical weapon in spider silk repels ant attack: New study

Researchers have shown for the first time how Golden orb web spiders (Nephila antipodiana) add a chemical to their web silk to repel invading ants. The finding adds a chemical defense to the impressive properties of spider silk, already known to be very strong, elastic and adhesive, and may provide new opportunities for pesticide design. The study was led by researchers from the National University of Singapore (NUS) and the University of Melbourne, and is published in the journal Proceedings of the Royal Society B today. Associate Professor Daiqin Li, who led the team at the National University of Singapore, said that ants rarely occur on the web of orb web spiders, despite their abundance, so his team set out to discover why. "We found that large Golden orb web spiders add a defensive alkaloid chemical onto the silk, which stops the ants from walking onto the web when they come into with it," said Assoc Li from the Department of Biological Sciences, NUS. Professor Mark Elgar from the University of Melbourne's Department of Zoology said the team was impressed by the strength of the ant repellent in the web silk. "The type of chemical deterrent found in the spider silk is known as a pyrrolidine alkaloid, which acts as a predator deterrent in many species of ants, moths and caterpillars," Elgar said.