Baby spiders behind drifting silk-like strands

Hundreds of thousand of juvenile money spiders are being blamed for a natural phenomenon that has prompted calls to the Northland Regional Council recently.


Council Biosecurity Officer Ross Johnson says Council biosecurity and air quality staff have logged calls from members of the public concerned by large amounts of a silk-like substance floating in the air and settling.


“That’s exactly what it is – spider silk.”


Mr Johnson says on still days, especially in late autumn and early winter, spiderlings (baby spiders) can throw out a long single thread of silk.


It’s an attempt by the spiders to be picked up by thermals and light winds, allowing them to be transported long distances in a clever natural process called “ballooning”.


He says many people don’t release that spiders can actually make several different types of silk and the ballooning process involves a different type of silk than that more commonly seen in webs.


Mr Johnson says the threads don’t last very long, and the spiders attached to them pose no threat, but the phenomenon can be can a “wonderful sight”, with paddocks, trees, tractors and anything else in their path draped in a blanket of fine silk.


He says the recent reports had come from several areas around the Whangarei District with Landcare Research experts confirming the most likely culprits were hundreds of thousands of young money spiders “ballooning” at the same time.