The black widow proceeded to build its characteristic cobweb right under its cage. Han noticed the messy upper part where the spider hung out and an array of vertical threads glued to the ground.

Entomologist Sarah Han has always been into spiders. "I grew up in California and there are a lot of black widows," says Han. "I would keep them as pets. One day, one of them escaped. That's a mistake ...

Outdoor spiders are hard at work, devouring home and garden pests such as ants, flies, mosquitoes, aphids, and thrips. It’s estimated they kill 400 to 800 million metric tons of prey worldwide ...