The term “daddy long legs” is commonly used, yet it frequently causes confusion regarding whether these creatures pose any threat. This common name refers to several distinct types of animals, each with unique characteristics. Understanding these differences is key to dispelling misconceptions about their potential to cause harm.
Unpacking the Name Daddy Long Legs
The popular name “daddy long legs” is applied to at least three different groups of arthropods. First, there are harvestmen, belonging to the order Opiliones, which are arachnids but not true spiders. Harvestmen have a single, fused body segment, making their body appear oval or spherical, unlike spiders which have two distinct body parts. They possess eight long, thin legs, with the second pair often longer and used for sensory functions.
Another group commonly called “daddy long legs” are cellar spiders, members of the family Pholcidae. These are true spiders, characterized by their small bodies and exceptionally long, delicate legs. Cellar spiders construct irregular, messy webs, often found in corners of basements and other undisturbed areas. Unlike harvestmen, cellar spiders have two distinct body segments and typically eight eyes.
Lastly, the term can refer to crane flies, which are insects belonging to the family Tipulidae. These creatures resemble oversized mosquitoes with slender bodies, long, fragile legs, and a single pair of wings. Crane flies are distinguished from mosquitoes by their snout-like mouths and lack of scales on their wing veins. Their hind wings are reduced to small, club-like structures called halteres, which assist with balance during flight.
Assessing Their Perceived Threat
The concern about “daddy long legs” often stems from pervasive myths about their venom and biting capabilities.
Harvestmen are entirely harmless to humans and pets. They do not possess venom glands, nor do they have fangs capable of injecting venom. Their mouthparts are designed for chewing and tearing food, not for biting to deliver toxins. The urban legend claiming they are highly venomous but cannot bite due to short fangs is unfounded.
Cellar spiders, while true spiders that produce venom, are generally not considered a threat to humans. Their fangs are typically too short or too weak to effectively penetrate human skin. Bites from cellar spiders are extremely rare and, if they occur, are usually harmless, often resulting in only mild irritation.
Crane flies are completely harmless to humans. They do not bite or sting, and they are not known to transmit diseases. Adult crane flies often have non-functional mouthparts or feed only on nectar, focusing primarily on reproduction during their short adult lifespan. Their large size and awkward flight might appear intimidating, but they pose no danger.
Their Role in the Ecosystem
Beyond their perceived threat, these creatures contribute to various ecological processes. Harvestmen are omnivorous, functioning as scavengers by feeding on decaying plant and animal matter, fungi, and bird droppings. They also act as opportunistic predators, consuming small insects, mites, and other soft-bodied arthropods, which can include garden pests like aphids. Their diet helps in nutrient cycling and maintaining ecological balance.
Cellar spiders are beneficial predators, actively hunting and consuming other insects and spiders. They are known to prey on common household pests such as mosquitoes, flies, and even other spiders, including more commonly feared species like black widows. Their presence can therefore contribute to natural pest control within homes and other structures.
Crane flies, particularly in their larval stage, play a role in ecosystem decomposition. The larvae, often called “leatherjackets,” feed on decaying organic matter, plant roots, and sometimes small invertebrates in moist soil or aquatic environments. This feeding activity helps break down dead plant material and return nutrients to the soil. Adult crane flies also serve as a food source for various animals, including birds, bats, lizards, and other insects.