The term “daddy long legs” often refers to creatures with long, thin legs, but its identity causes widespread confusion. This common name can refer to several distinct animals. This article clarifies the mystery by distinguishing between these creatures and shedding light on their true characteristics, dispelling common myths and appreciating their roles in our environment.
Who Are the “Daddy Long Legs”?
The common name “daddy long legs” is broadly applied to at least three different arthropods, leading to misidentification. These are harvestmen (order Opiliones), cellar spiders (family Pholcidae), and crane flies (family Tipulidae). Harvestmen are arachnids but not true spiders. Cellar spiders are true spiders. Crane flies are insects, more closely related to mosquitoes than to spiders.
Understanding Harvestmen
Harvestmen (order Opiliones) are often mistaken for spiders due to their eight legs, but have distinct anatomical differences. Unlike spiders, harvestmen have a fused body, appearing as a single oval segment, rather than the two-part body (cephalothorax and abdomen) of true spiders. Most species have a single pair of eyes on a raised structure.
They do not spin webs for prey capture, as they lack silk glands. Their diet includes small, soft-bodied insects, mites, plant matter, and decaying organic material. They capture food using small, pincer-like mouthparts called chelicerae. These arachnids are harmless to humans, possessing no venom glands or fangs capable of piercing human skin.
The Cellar Spider Explained
Cellar spiders (family Pholcidae) are true spiders commonly called “daddy long legs.” They feature a body clearly divided into two parts: a cephalothorax and an abdomen. They typically have eight clustered eyes, and their most striking feature is their exceptionally long, thin legs.
Cellar spiders construct irregular, messy webs, frequently found in sheltered, damp areas such as basements. They are predatory, using their webs to capture insects including mosquitoes, gnats, moths, and flies. Cellar spiders also prey on other spiders, sometimes vibrating webs to mimic trapped prey. Like all true spiders, they possess venom to subdue their prey.
Dispelling the Venom Myth
A widespread urban legend claims “daddy long legs” possess the world’s most potent venom but cannot bite humans due to short fangs. This myth is unfounded and combines misconceptions about harvestmen and cellar spiders.
Harvestmen (order Opiliones) do not produce venom and lack fangs; their pincer-like mouthparts cannot break human skin. Cellar spiders, while true spiders and venomous, pose no significant threat to humans. Their venom is mild, comparable to a mosquito bite, and primarily effective against insect and spider prey. Though their small fangs can penetrate human skin, bites are rare and typically cause only minor, localized irritation. The “most venomous” claim is not supported by scientific evidence.
Their Place in the Ecosystem
Both harvestmen and cellar spiders play beneficial roles within their ecosystems. Cellar spiders act as natural pest controllers in human dwellings, preying on household insects like flies, mosquitoes, and other spiders. Their presence helps manage indoor pest populations.
Harvestmen, found in gardens and natural landscapes, contribute to ecological balance as scavengers and predators. They consume small garden pests (aphids, mites, slugs) and aid decomposition by feeding on decaying plant and animal matter. Both groups serve as a food source for larger animals, including birds, amphibians, and other arachnids.