The Lesser of Two Evils?

A graduate student in Florida discovered that the banana spider preferred cockroaches to flies. Later she moved into a house and found some 300 roaches there ahead of her. She released 15 banana spiders in the house. Four weeks later, no more roaches. The spiders are nonpoisonous to humans, spin no webs and are nocturnal. “They’re better to have around than the roaches,” she decided. Do you agree?