“Daddy long legs” is a common term that refers to several distinct arthropods. Despite their similar common name and often spindly appearance, these creatures belong to different biological groups. Understanding when and why they appear involves distinguishing between these types and exploring their unique life cycles and habits.
Identifying Daddy Long Legs
The term “daddy long legs” commonly applies to three different types of arthropods: harvestmen, cellar spiders, and crane flies. Harvestmen, belonging to the order Opiliones, are arachnids but are not true spiders. They have a single, oval-shaped body segment with no distinct waist, unlike spiders which have two body parts. Harvestmen also possess two eyes, which can only sense light and dark, and they cannot produce silk or webs.
Cellar spiders, part of the family Pholcidae, are true spiders characterized by their extremely long, thin legs and small, often pale yellow to light brown or gray, oval bodies. They spin loose, irregular webs, found in undisturbed, damp areas. Unlike harvestmen, cellar spiders have eight eyes and produce silk. Crane flies, classified as insects in the family Tipulidae, differ significantly as they possess wings and only six legs. They resemble large mosquitoes but do not bite.
Their Seasonal Appearance and Preferred Habitats
Harvestmen are frequently observed in late summer and early fall, when their populations increase. They prefer moist, shaded outdoor environments, often found under rocks, mulch, or in other hidden locations, avoiding direct sunlight.
Cellar spiders are found indoors throughout the year, thriving in warm, stable temperatures. They commonly inhabit damp, dark spaces such as basements, cellars, garages, and crawl spaces, where they construct their messy webs in corners. Their presence indoors is as they seek shelter and feed on other insects. Crane flies, being winged insects, are most noticeable during warmer months, often attracted to lights at night, which can lead them indoors. They are predominantly found outdoors in moist, wooded areas.
Life Cycle and Daily Activities
Harvestmen are omnivores, consuming small insects, fungi, plants, and decaying organic matter. They do not use venom or silk for hunting, instead ambushing their prey or scavenging. Their life cycle involves maturation in autumn, contributing to their increased visibility. Many species are nocturnal, hiding during the day and becoming active at night.
Cellar spiders are predatory, feeding on various insects like flies, mosquitoes, and ants, and are known to prey on other spiders, including larger house spiders. They create irregular webs to capture prey, sensing vibrations to locate their next meal. These spiders can live for up to two years, hunting and reproducing year-round. Crane flies undergo a life cycle with egg, larval, pupal, and adult stages. Adult crane flies have short lifespans, often only a few days, and many species do not feed at all in their adult form. Their larvae, sometimes called “leatherjackets,” feed on decomposing organic matter in moist environments.
Debunking Common Myths
A persistent myth suggests that “daddy long legs” possess extremely potent venom but cannot bite humans due to small fangs. This claim is untrue. Harvestmen, for instance, are not venomous and lack fangs altogether, possessing pincer-like jaws instead. They are entirely harmless to humans.
Cellar spiders, while true spiders, do produce venom like most spiders. However, their fangs are very small, making it difficult for them to penetrate human skin, and there is no evidence of them causing harmful reactions from bites. Crane flies are insects and are non-venomous and non-predatory, with adult mouthparts incapable of piercing skin.