A HUGE web in the backyard of a Pialba mum's home has now disappeared - just as an arachnid expert promised it would.
Denise Torkington had never seen anything like the huge spiders' web forming under her children's trampoline last month.
But the mystery has been cleared up by the Queensland Museum's arachnid expert Robert Raven.
He says the huge web is a natural phenomenon used by spiderlings to disperse into the air and migrate to a new location.
"The phenomenon is called ballooning and consists of the spider pulling a thread of silk, liquid when formed but forming a strand under pressure, out of their spinnerets," the senior curator of arachnology said.
"The silk is very light and easily lifted in the warm updrafts that form in the morning.
"Once enough silk is out and the drag on it strong, the spider releases its hold on the plant and floats skyward."
Ms Torkington was told the spiders would probably "balloon" away from her backyard soon.
She and her husband moved the trampoline off the web and, a day later, most of the spiders had disappeared.
"The day after that, all of them were gone," Ms Torkington said.
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