The black widow spider, recognized by its glossy black body and distinct red hourglass marking, holds a formidable reputation for its potent venom. Despite being one of North America’s most venomous spiders, it is not without its adversaries. A variety of animals prey on this arachnid, navigating its defenses and overcoming its toxic bite. These predators range from other invertebrates to various vertebrates.
Insects That Prey on Black Widows
Specialized insects frequently target black widow spiders. Mud dauber wasps, such as the blue mud dauber (Chalybion californicum), are prominent predators. These wasps paralyze the black widow with a precise sting, preserving it as a living food source for their developing larvae. The paralyzed spider is then sealed within a mud cell. Some mud daubers even employ a clever tactic of tapping the black widow’s web to lure it out before striking.
Spider wasps, belonging to the Pompilidae family, also specialize in hunting spiders, including black widows. They deliver a paralyzing sting before taking the incapacitated spider back to their nests for larval consumption. Praying mantises are opportunistic hunters that will readily prey on black widows. Their swift reflexes and strong forelegs allow them to quickly grab the spider, preventing it from biting, and then consume it.
Other Invertebrate Hunters
Other invertebrates also pose a threat to black widows. Cannibalism is observed within the black widow species, with females occasionally consuming males after mating, and spiderlings eating their siblings. Brown widow spiders may also displace black widows through predation.
Cellar spiders (Pholcidae family), often called “Daddy Longlegs,” actively hunt and consume black widows. These spiders capture prey significantly larger than themselves by casting long swaths of silk onto their target, binding it securely from a distance. Centipedes, as generalist predators, can also subdue and feed on black widows.
Vertebrate Predators
Vertebrates also include black widows in their diet, often as opportunistic feeders. Bird species, such as wrens, mockingbirds, and bluebirds, feed on spiders, though some may experience an upset stomach from black widow toxins. Small mammals like shrews and nocturnal rodents also prey on black widows.
Among reptiles, the alligator lizard (Elgaria multicarinata) is a notable predator of black widows. These lizards actively seek and consume the spiders, demonstrating a remarkable resistance to their venom. Western fence lizards (Sceloporus occidentalis) also show a degree of resistance to black widow venom. While some amphibians and snake species may occasionally consume black widows, many reptiles avoid them due to potential digestive upset from toxins.
How Predators Overcome Venom and Defenses
The ability of these animals to prey on black widows often stems from specific adaptations. Some predators possess a natural resistance or immunity to the spider’s venom. Alligator lizards, for instance, have physiological mechanisms that can block or neutralize the venom’s effects, potentially involving proteins that bind to and disable the toxins. This allows them to consume multiple black widows without apparent ill effects.
Many predators employ specialized hunting techniques to avoid the black widow’s bite. Wasps, for example, deliver a paralyzing sting that incapacitates the spider before it can retaliate. Praying mantises use their speed and powerful forelegs to quickly seize the black widow, preventing it from deploying its fangs. Cellar spiders utilize their long legs to cast silk from a distance, binding the black widow safely before engaging directly.