University of California, Riverside, arachnologist Rick Vetter is asking Orange County residents to mail him the spider's distinctive, spiky egg sacs so that scientists can learn more about the species, KTLA-TV, Los Angeles, reported Thursday.
Brown widows are native to southern Africa have been seen all over Southern California since they were first spotted in Torrance eight years ago.
Their bite, though poisonous, is less harmful than that of their black widow cousins that frequent the same areas, Vetter said.
Brown widows prefer to build their webs around vegetation, he said, so there's a greater chance of people being bitten while outside in a garden.
"They could be in the curled leaf of a bird of paradise, a citrus tree," Vetter told the Orange County Register, "[or in] those little lights you stick in the ground -- the solar powered night-lights for a pathway."
Brown widows hiding inside toys left outside can bite children, he said.
"These things are found in a lot of places where you would think they would be exposed to humans, and there's a possibility of contact and bites," he said.