Black widow spiders are known for their potent venom, a neurotoxin that can cause significant effects. Despite their defenses, these spiders are not at the top of the food chain and exist within complex ecological networks. Like all organisms, black widows serve as a food source for various animals, demonstrating they have natural predators.
Animals That Prey on Black Widows
Various animals across different taxonomic groups are known to prey on black widow spiders. Other arachnids, such as larger spider species, can overpower and consume black widows. For instance, the desert tarantula (Aphonopelma chalcodes) and the cellar spider (Pholcus phalangioides) have been observed preying on black widows, often by overwhelming them or trapping them in their webs. Certain scorpions also prey on black widows, utilizing their own venom to incapacitate the spider before consumption.
Insects are a significant group of black widow predators, particularly various species of wasps. Spider wasps (Pompilidae family), including the blue mud dauber (Chalybion californicum), sting and paralyze black widows, then transport them to a burrow for their developing larvae. Robber flies (Asilidae family) are opportunistic predators that capture and consume black widows in their natural habitats. Praying mantises are generalist predators known to feed on a variety of insects and spiders, including black widows, using their powerful forelegs to grasp and subdue their prey.
Birds are common predators of many spider species, and some will consume black widows. Birds like scrub jays and chickens eat black widows, often snatching them from their webs. Small mammals, such as shrews, mice, and some bats, may also prey on black widows, particularly if they encounter them outside their webs or in accessible locations. Certain reptiles and amphibians, including lizards and frogs, may occasionally consume black widows as part of their varied diet.
How Predators Manage Black Widow Venom
Predators use diverse strategies to manage or overcome black widow venom. Some animals have natural resistance or immunity to the venom’s neurotoxic components. For example, shrews and grasshopper mice have evolved adaptations allowing them to tolerate the venom with minimal adverse effects.
Other predators use physical tactics, relying on speed, strength, or specific attack methods to subdue the spider without being bitten. Spider wasps, for example, deliver a precise sting that quickly paralyzes the black widow, preventing retaliation. They then transport the immobilized spider, ensuring they are not exposed to its defensive bite. Larger predators, such as some birds or mammals, are often too big for the venom to have a significant systemic effect, as the dose received relative to their body mass is insufficient to cause severe harm.
Some predators target vulnerable parts of the black widow’s body to minimize risk. They may aim for the cephalothorax, which houses the brain and venom glands, or rapidly wrap the spider in silk to incapacitate it before a fatal bite.