The term “daddy long legs” frequently leads to confusion, as it is commonly applied to more than one type of arachnid. This widespread use can obscure whether the creature in question is a true spider and, consequently, if it possesses the ability to produce silk and construct webs. Understanding the distinct biological classifications of these creatures is important to clarify their web-making capabilities.
Understanding “Daddy Long Legs”
The term “daddy long legs” most often refers to two distinct arachnid groups: Harvestmen (order Opiliones) and Cellar Spiders (family Pholcidae). While both share the characteristic of having exceptionally long, slender legs, their body structures and other features exhibit notable differences. Harvestmen possess a fused body, meaning their cephalothorax and abdomen appear as a single, oval segment. In contrast, Cellar Spiders, like all true spiders, have two distinct body segments connected by a narrow stalk.
Beyond body segmentation, their eye arrangements also differ significantly. Harvestmen typically have two eyes, often positioned on a raised mound called an ocularium, centrally located on their fused body. Cellar Spiders, however, generally have eight eyes, though some species may have six, usually grouped in a specific pattern on their cephalothorax.
Harvestmen: Non-Web Spinners
Harvestmen (Opiliones) are arachnids, but they are not true spiders and, as such, do not produce silk or build webs. Their anatomy lacks the silk glands and spinnerets necessary for silk production. Instead of relying on webs for capturing prey, Harvestmen are primarily scavengers, feeding on decaying plant and animal matter, or opportunistic predators of small insects and other invertebrates. They use their long legs to explore their environment and locate food sources.
These arachnids typically inhabit damp, shady areas such as leaf litter, under rocks, or beneath tree bark, and are often nocturnal. When threatened, some species can release defensive secretions from scent glands, which may deter predators.
Cellar Spiders: Web Builders
Cellar Spiders (Pholcidae) are indeed true spiders and possess the biological machinery to produce silk and construct webs. They build irregular, messy, tangled webs, often found in undisturbed, dark corners of basements, cellars, and other quiet indoor areas. These webs are not sticky, relying instead on their complex, three-dimensional structure to ensnare prey.
Cellar spiders typically hang inverted within their webs, waiting for prey to become entangled. Once prey is detected, they quickly wrap it in silk before delivering a venomous bite. These spiders are also notable for their “vibrating” behavior; when disturbed, they rapidly gyrate in their web, making themselves difficult for predators to see or catch. Cellar spiders are effective predators, capable of catching various insects and even other spiders, including larger house spiders.