Yes, if “daddy long legs” means the cellar spider. That thin-legged spider of basement corners can catch and eat black widows, and it does. Its weapon isn’t powerful venom, despite the famous legend. It fights from a distance, and the two other creatures that share the name aren’t known to hunt widows at all.
Which Daddy Long Legs Kills Black Widows
People use “daddy long legs” for three unrelated creatures: the cellar spider, the harvestman and the crane fly.1UF/IFAS Extension Manatee County. A Tale of Three Daddy Long Legs Only the cellar spider is a true spider. The harvestman is an arachnid but not a spider, and the crane fly is an insect.2Northwest Exterminating. Cellar Spider vs Daddy Long Legs: Key Differences So any claim about daddy long legs killing widows only makes sense for the cellar spider.
Cellar spiders trap and eat other spiders of many kinds, including black widows and brown recluses.3Bulwark Pest Control. Cellar Spiders They capture spiders in the black widow group in particular.4Missouri Department of Conservation. Cellar Spiders
Telling the three apart is easier than it sounds. A cellar spider has a small two-part body and very thin legs, and it hangs upside down in a messy web. A harvestman has one round, bean-like body, never builds a web, and walks on the ground or walls. A crane fly has wings and looks like a giant mosquito, often near lights.
Harvestmen don’t fit the widow-killer role. They eat a wide mix of small soft-bodied creatures, live or dead, such as worms and insects.5The Journal of Arachnology. Diet, predators, and defensive behaviors of New Zealand harvestmen (Opiliones: Neopilionidae) They’re also often prey themselves, eaten by spiders, frogs, lizards and birds.6The Journal of Arachnology. Diet, predators, and defensive behaviors of New Zealand harvestmen (Opiliones: Neopilionidae)
Cellar spiders and widows end up in the same places because both like quiet, sheltered spots such as basements, garages, sheds and crawl spaces. Cellar spiders build loose tangled webs in ceiling corners and under shelves. Widows build low, messy, strong webs near the floor or in clutter. That overlap is why encounters happen.
How a Fragile Spider Beats a Black Widow
A cellar spider casts long swaths of silk onto its prey and ties it up from a safe distance.7Missouri Department of Conservation. Cellar Spiders Its usual first move against a spider or insect is to throw silk, and only then bite.8ZoologyNotes. Cellar Spiders – As Interesting as they are Common It has been seen hanging with as few as two legs on its web while flinging silk at prey away from the web.9ZoologyNotes. Cellar Spiders – As Interesting as they are Common
The long legs are a safety tool. They let the cellar spider wrap silk around prey without putting its body at risk.10Missouri Department of Conservation. Cellar Spiders The thin legs also give an attacker little to grab and keep the body out of range of a counterattack.11ZoologyNotes. Cellar Spiders – As Interesting as they are Common
Venom strength doesn’t decide this fight. The winner is the one who avoids being bitten. Restraining the widow first removes its chance to use its own venom. Once silk lands, sticky strands across the body and legs limit movement, so the widow can’t lunge or turn its fangs toward the attacker.
Snakes and many other predators inject venom to subdue prey. The cellar spider reverses the order, restraining first and biting second, so its venom is more of a finishing and feeding tool than the thing that wins the encounter.
The Most Venomous Spider Myth
A popular legend says daddy long legs are the most venomous spiders but their fangs are too short to bite you. The short answer is no.12Department of Entomology. Are daddy longlegs really the most venomous spiders in the world? The myth probably grew from cellar spiders killing widows, which people assumed meant stronger venom.13Missouri Department of Conservation. Cellar Spiders Cellar spider venom is actually rather mild compared with other spiders.14Missouri Department of Conservation. Cellar Spiders
Tested on crickets, one cellar spider’s venom works about as well as that of similar primitive spiders, nothing exceptional.15Frontiers in ecology and evolution. Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus In one cellar spider species, the mouthparts can pierce human skin.16PubMed Central. Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus A bite causes only a mild sting with no lasting effects,17Frontiers in ecology and evolution. Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus and venom from a single cellar spider can’t kill a person or other mammal.18PubMed Central. Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus
Harvestmen aren’t spiders and have no venom glands at all, so the “deadliest venom” story is wrong for them twice over.
If a cellar spider does bite you, expect a brief sting like a small pinch that fades. Wash the spot with soap and water. Seek care only if you see unusual swelling or signs of infection, as with any small wound.
Should You Keep Cellar Spiders to Control Black Widows
Leaving a few cellar spiders in a garage or basement does no harm and may reduce some pests.19Bulwark Pest Control. Cellar Spiders They won’t clear a space of widows, because each one only affects the small area around its web. Think of them as a bonus in a space you’re already managing, not a replacement for doing the work.
Cellar spiders only catch widows that come near their webs. Widows tend to stay low, tucked into clutter, boxes and corners near the floor, where they build strong, tangled webs. Cellar spiders hang upside down in higher corners, so the two often live in different layers of the same room. A widow can sit in a woodpile or behind a stack of pots for months without ever touching a cellar spider’s web. So reduce clutter, seal gaps and wear gloves in widow spots no matter how many cellar spiders you have.
Put on thick gloves before lifting boxes, firewood, pots or old tools that have sat on the floor undisturbed, since widows hide under and behind them. Look at the underside of each object as you lift it, so you see a widow before your hand reaches it. Before wearing shoes or gloves stored in a garage or shed, turn them upside down and shake them hard.
Moving stored items off the floor onto shelves and keeping stacks away from walls removes the dark, cluttered spots widows prefer. Seal cracks and gaps near the floor and around doors and pipes, which cuts both entry points and hiding spots. Do this as a one-time cleanup, then check occasionally, since widows return to undisturbed clutter. A vacuum takes care of any widow webs and egg sacs you find.
Cellar spiders can become a nuisance of their own. Their webs gather dust and look messy in corners. Vacuuming the webs keeps numbers down without chemicals, though removing them also removes their small benefit, so it’s a trade-off.
What Else Eats Black Widows
Some lizards eat widows and shrug off the venom. Southern alligator lizards in the western U.S. ran just as fast after doses of widow venom up to about six times a widow’s typical bite.20PubMed Central. Preying dangerously: black widow spider venom resistance in sympatric lizards Bony plates in their scales likely block bites, and their muscles showed no damage.21PubMed Central. Preying dangerously: black widow spider venom resistance in sympatric lizards
Western fence lizards kept running near normal speed despite some muscle damage.22PubMed Central. Preying dangerously: black widow spider venom resistance in sympatric lizards Small side-blotched lizards were badly slowed and are sometimes eaten by widows instead.23PubMed Central. Preying dangerously: black widow spider venom resistance in sympatric lizards
For a yard, lizards may help limit widows somewhat. Rock piles or brush kept at a distance from the house can shelter lizards without putting widow hiding places against your walls. Don’t assume every lizard you see is helping, since size and armor matter and small, thin-skinned lizards may be vulnerable themselves.
Widows have other enemies too. Some wasps hunt widows to feed their young, and birds may take exposed widows. Most predators only dent numbers rather than wipe widows out.
Are Harvestmen and Crane Flies Harmful
Neither can hurt people. Harvestmen defend themselves passively: some drop a leg or play dead when attacked.24The Journal of Arachnology. Diet, predators, and defensive behaviors of New Zealand harvestmen (Opiliones: Neopilionidae) One heavily armored harvestman resisted a large spider through its hard body, not its smelly defensive chemicals.25Animal Behaviour. Harvest-ironman: heavy armature, and not its defensive secretions, protects a harvestman against a spider
Dropping a leg lets a harvestman escape when a predator grabs it, and the detached leg may keep twitching, which can distract the attacker. Playing dead makes the animal look uninteresting to predators that go for moving prey. Many species also have a hard or armored body that makes them difficult to eat. A harvestman won’t regrow a lost leg, but it can usually keep getting around on the rest.
Harvestmen have no venom glands and no silk, so they have nothing to bite or sting with that matters to people. Adult crane flies don’t bite or sting people and don’t hunt spiders.
To move a harvestman, gently scoop it into a cup, slide a card under, and release it outside, or just let it walk onto your hand. A crane fly gravitating toward a lamp or window can be guided to an open window or door, and it will usually leave on its own. Skip pesticides for both, since they pose no danger and a spray adds risk without solving anything.