The question of how long “daddy long legs” live in a house is common, often leading to confusion due to the general use of the term. These long-legged arachnids are frequently encountered indoors, prompting curiosity about their longevity. Understanding their lifespan requires clarifying what creature the term refers to, as it can apply to different arthropods with varying biological characteristics.
Unpacking the “Daddy Long Legs” Term
The term “daddy long legs” commonly refers to two distinct arachnids: harvestmen (Opiliones) and cellar spiders (Pholcidae). While both possess notably long, thin legs, they are not the same. Harvestmen have a single, fused body segment, appearing rounded. They do not spin webs or produce venom, instead using pincer-like mouthparts for food.
Cellar spiders are true spiders, characterized by two distinct body segments—a cephalothorax and an abdomen—connected by a narrow waist. They possess fangs and silk-producing spinnerets, which they use to construct irregular webs to capture prey. This fundamental difference leads to variations in their behavior and survival, including their lifespan.
Lifespan in Domestic Environments
The lifespan of “daddy long legs” in a house varies significantly depending on whether it is a harvestman or a cellar spider. Harvestmen generally have a shorter lifespan, typically living for about one year. Their life cycle is often tied to seasonal changes, with eggs laid in the fall and young emerging in the spring, maturing by late summer or early fall. While some may survive milder winters in sheltered indoor locations, they are not primarily indoor creatures, and their presence inside is often temporary.
Cellar spiders are well-adapted to indoor environments and can live considerably longer, typically one to three years, sometimes more. They take roughly one year to mature from egg to adult. Female cellar spiders can produce multiple egg sacs, each containing numerous offspring, contributing to their sustained presence within a home.
Factors Influencing Indoor Survival
Several environmental and resource factors within a house influence the longevity of both harvestmen and cellar spiders. Food availability is a primary determinant. Cellar spiders are opportunistic predators, feeding on various small insects like mosquitoes, gnats, moths, flies, and other spiders. A consistent supply of these prey items can support a cellar spider population for extended periods.
Harvestmen, being omnivores and scavengers, consume decaying plant matter, fungi, small insects, and dead animals. Water and humidity also play a role. Harvestmen prefer damp, shaded areas, and low humidity can be detrimental. Cellar spiders also favor damp locations like basements and crawl spaces, where humidity is higher.
Stable indoor temperatures provide a consistent environment conducive to their survival. The absence of natural outdoor predators also contributes to their increased indoor lifespan.
Their Presence in Your Home
“Daddy long legs” often find their way into homes seeking shelter from harsh outdoor conditions or food. Both harvestmen and cellar spiders are generally considered harmless to humans and pets. Harvestmen lack venom glands and fangs, making them incapable of biting or posing a threat.
Cellar spiders, while possessing venom and fangs, rarely bite humans, and their venom is considered mild and not dangerous to people. Their presence can be beneficial, as cellar spiders prey on other common indoor pests, including flies, mosquitoes, and other spider species. Their long-legged forms often represent a benign and sometimes helpful addition to the indoor ecosystem.