When conditions are just right, when dry conditions that delay spider hatching are followed closely by heavy rains causing dramatic increases in airborne spider food like mosquitoes, spider populations can explode as massive numbers of new hatchlings appear simultaneously. When the heavy rains turn to flooding, that newly created legion of spiders must migrate up to seek shelter from the rising waters.
To reach safety, the spiders practice a behavior known as ballooning, spinning fine strands of silk that catch the breeze and lift them high into the air. If the breezes are insufficient, however, an extraordinary amount of silk and baby spiders can land in the same place.
This exact confluence of unusual events occured in Wagga Wagga, Australia in March of 2012 following widespread flooding. ABC News Australia reported “entire paddocks and trees swathed in silver silk,” and that “you cannot walk down the road without swarms of tiny brown spiders crawling up your legs,” as hundreds of thousands of spiders transformed fields into deceptively innocent-looking banks of fleecy snow, like some abhorrent cotton candy from an arachnophobe’s nightmare.
Similar massive spider webs were reported previously in Australia in 2007 following flooding in Gippsland, and in 2010 in Pakistan, when a decade’s worth of rain fell across the country in one week, submerging more than a fifth of the entire country. Although the thick, eerie shrouds of cobwebs may loom like horrible phantasms to some (and can damage trees if conditions persist), officials are quick to point out that the spiders’ presence helps to reduce the incidence of disease-carriers like mosquitoes, which can breed in the abundant stagnant water after a flood. Smaller spider mass dispersion incidents have also been observed without the benefit of flooding, such as the sprawling 2007 Lake Tawokoni State Park web in Texas that covered trees and trails for nearly 200 meters.
Take a look through the gallery below for photos of hatchlings and giant webs in Sindh, Pakistan, Lake Tawakoni, Texas, and Gippsland and Wagga Wagga Australia, and decide if this is one oddity you’d prefer to marvel at from a safely spider-free distance.