A common belief suggests that the arachnid often called “daddy long legs” is a formidable predator capable of killing the venomous black widow spider. This article explores the scientific basis behind this widespread urban legend. By understanding their true natures, we can clarify the actual interactions, or lack thereof, between these arachnids.
Unpacking the “Daddy Long Legs” Identity
The common term “daddy long legs” causes confusion, referring to at least two distinct arachnid types. One group includes true spiders from the family Pholcidae, known as cellar spiders, which possess delicate bodies, long legs, and construct irregular, messy webs.
Another arachnid frequently called “daddy long legs” is the harvestman, which belongs to the order Opiliones. Harvestmen are not true spiders; they have a fused body segment and lack venom glands and silk-producing spinnerets. Unlike cellar spiders, harvestmen do not possess fangs for injecting venom.
The Black Widow’s Nature
Black widow spiders, primarily species within the genus Latrodectus, are well-known for their potent venom and characteristic appearance. These spiders typically exhibit a shiny black body, often marked with a red or orange hourglass shape on the underside of their abdomen. Black widows prefer to build their irregular, tangled webs in secluded, undisturbed locations, such as woodpiles, sheds, and beneath outdoor furniture.
Their venom is neurotoxic, meaning it affects the nervous system of their prey and, in rare cases, humans. A bite from a black widow can cause symptoms like muscle pain, abdominal cramps, and nausea. While their venom is potent, black widow spiders are generally not aggressive and will typically bite only when they feel threatened or are accidentally disturbed within their web.
Dispelling the Myth: The Truth About Their Interactions
The widespread myth that “daddy long legs” kill black widows largely refers to cellar spiders (Pholcidae) due to their predatory nature. Cellar spiders possess small fangs and produce a mild venom, which they use to subdue their prey. This venom is not potent to humans and primarily serves to immobilize small insects or other spiders.
Their fangs are often too small and weak to effectively pierce the tough exoskeleton of a larger spider like a black widow. While cellar spiders are generalist predators and will occasionally capture other spiders, there is no scientific evidence they specifically target or regularly prey upon black widows. Observations of cellar spiders consuming black widows are rare and likely opportunistic encounters rather than specialized predation.
Why the Myth Endures
The persistence of the myth that “daddy long legs” kill black widows can be attributed to several factors. Anecdotal observations, where people occasionally see a cellar spider and a black widow in proximity, lead to misinterpretations. A cellar spider might incidentally capture a black widow that blunders into its web, which could then be misconstrued as a deliberate hunt.
The myth also endures because it presents an appealing narrative of a seemingly harmless creature overcoming a dangerous one. The confusion surrounding the identity of “daddy long legs” contributes to the myth’s longevity, as the distinct biological characteristics of true spiders versus harvestmen are often not widely understood.