The question of whether “daddy long legs” consume other spiders is common, sparking curiosity about these long-limbed creatures. Many people encounter them in their homes and wonder about their feeding habits. Understanding that the term “daddy long legs” refers to more than one animal, each with distinct characteristics and diets, is key. This distinction clarifies the popular misconception surrounding their predatory behavior.
Unmasking the “Daddy Long Legs”
The common name “daddy long legs” applies to two distinct arachnids, leading to frequent confusion. One group consists of harvestmen (order Opiliones). These are not true spiders; their body segments are fused, appearing as a single oval structure. Harvestmen lack venom glands and do not produce silk, so they cannot spin webs. They typically have only two eyes, located on a raised tubercle.
The other creature is the cellar spider (family Pholcidae). These are true spiders, characterized by two distinct body segments and the ability to spin webs. Cellar spiders have extremely long, thin legs and are found in basements, garages, and other undisturbed areas. Most species have eight eyes, though some have six.
Dispelling the Spider-Eating Myth
The notion that “daddy long legs” universally eat other spiders is largely a myth, especially for harvestmen. Harvestmen do not eat spiders. Their feeding mechanism involves grasping and tearing food with pincer-like mouthparts.
Conversely, cellar spiders do prey on other spiders, including those much larger than themselves. These predatory true spiders use their messy, irregular webs to capture prey. Cellar spiders invade other spiders’ webs, vibrating the silk to mimic trapped prey, then attacking the unsuspecting host. This behavior allows them to consume various arachnids, including house spiders and black widows, which they subdue by rapidly wrapping them in silk before biting.
What They Truly Consume
Harvestmen have a diverse diet, primarily functioning as omnivores and scavengers. They consume small insects, plant matter, fungi, and decaying organic materials like dead insects and detritus. Unlike most arachnids, harvestmen can chew and consume solid pieces of food using their pincer-like chelicerae. They are often nocturnal and seek moist environments.
Cellar spiders, as active predators, primarily feed on small insects and other arthropods caught in their webs. Their diet commonly includes mosquitoes, gnats, moths, and flies. They are adept at hunting other spiders, casting long swaths of silk to bind prey from a safe distance. Their long legs provide an advantage, allowing them to keep larger prey at a distance during capture. If disturbed, cellar spiders may rapidly vibrate their webs, making themselves appear blurred to potential threats.