Australasian Science: Australia's authority on science since 1938

RepellAnt in Silk

By Stephen Luntz

Silk produced by golden orb-weaving spiders contains ant repellent.

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The silk produced by golden orb-weaving spiders is not merely strong, elastic and colour-coded to match locations, but it also contains ant repellent.

Ants represent more of a threat to spiders than potential prey, so it makes sense for spiders to keep them off their webs. Prof Mark Elgar of The University of Melbourne and a team from the National University of Singapore wondered why ants were so rarely observed on orb-weaver webs, despite their often-close proximity.

After washing silk from golden orb-weaving spider webs, Singapore’s Daiqin Li detected the presence of 2-pyrrolidinone, an alkaloid known to repel ants and moths.

“We encouraged ants to forage on a bait and took advantage of the fact they go straight back to their nests afterwards,” Elgar says. “We offered them three bridges to cross, one made of natural orb-weaver silk, and two with the chemicals washed off. They avoided the natural bridge and used the other two.”

The researchers added a drop of distilled water to one bridge and 2-pyrrolidinone to the other. The ants continued to use the watered bridge, but abandoned the one treated with the alkaloid.

Li says 2-pyrrolidinone is not a candidate for new insect repellents as it is believed to have carcinogenic properties. However, it is possible it may serve as a lead molecule towards more useful alternatives.


The full text of this article can be purchased from Informit.