Brown widow spiders’ aggression likely driver of black widow decline

Black widow spiders have earned a fearsome reputation for their venomous bite. But in parts of the southern United States these spiders have much to fear themselves — from spider relatives who really don’t like their company. In the past couple decades, researchers have noticed black widow spiders being displaced by the brown widow, a fellow species in the same genus. But new research suggests this isn’t a simple case of one species winning the competition for food or habitat. Instead, a study shows brown widow spiders have a striking propensity to seek out and kill nearby black widows.