Pholcus

Walckenaer, 1805

Common Cellar Spiders, daddy longlegs

Species Guides

Pholcus manueli(Manuel's Cellar Spider)
Pholcus opilionoides(Opilion-like Cellar Spider)
Pholcus phalangioides(Long-bodied Cellar Spider)

Pholcus is a large of cellar spiders in the Pholcidae, containing over 400 . The genus includes the widespread species P. phalangioides, commonly known as the long-bodied cellar spider or 'daddy longlegs'—a name shared with unrelated harvestmen and crane flies. Pholcus species are characterized by extremely long, thin legs and cylindrical bodies. They construct loose, irregular webs in dark, sheltered and exhibit distinctive defensive including rapid web-borne gyration ('whirling') when disturbed.

Pholcus phalangioides by (c) Michael, some rights reserved (CC BY), uploaded by Michael. Used under a CC-BY license.

Pholcus manueli by (c) Matthew Lindsey, some rights reserved (CC BY), uploaded by Matthew Lindsey. Used under a CC-BY license.

Pronunciation

How to pronounce Pholcus: //ˈfoʊkəs//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other pholcid by: body length greater than 4 mm; eight (not six); evenly domed prosoma without furrow or pit; cylindrical opisthosoma longer than high. The genus Pholcus is one of several pholcid genera referred to as 'cellar spiders' or 'daddy longlegs'; accurate identification to genus requires examination of eye arrangement and structure. -level identification often requires microscopic examination of genitalia, particularly in specimens.

Images

Appearance

Extremely long, thin legs relative to body size. Body length exceeds 4 mm in most . Eight arranged in two rows. Prosoma () evenly domed, lacking a furrow or pit. Opisthosoma () cylindrical, longer than high. Legs often appear fragile and translucent.

Habitat

Wild inhabit caves, under rocks, forest shrubs, and deep limestone cracks. species such as P. phalangioides occur in and around buildings, basements, cellars, window corners, and other disturbed . Some species occupy rock walls at elevations up to 213 m. Shade appears to be a primary requirement for web placement.

Distribution

Primarily distributed in the Palaearctic, Indo-Malayan, Afrotropical, and Australasian regions. The Pholcus kingi group represents the only native occurrence in the southeastern USA. Individual have specific ranges: P. phalangioides is in temperate and tropical regions worldwide; P. manueli is expanding its range in the United States; P. maxian is to the border region between Jilin, China and North Korea.

Diet

. Prey includes small insects and other arthropods: flies, beetles, , (observed for coastal preying on Seaside Dragonlets), field crickets, ground beetles, weevils, millipedes, and small . Some have been observed to kill and consume other spiders, including formidable species such as Australian redbacks (Latrodectus) and huntsman spiders.

Life Cycle

Females carry sacs in their (jaws), transporting them to reduce risk. Spiderlings hatch and may hitch a ride on the mother's body for a short period after . Sperm mixing occurs: females mate with multiple males, and sperm from the last mating has highest probability. Males remove rival sperm from females prior to depositing their own.

Behavior

Constructs loose, irregular, tangled webs ('cobwebs') in corners and sheltered locations. Exhibits 'whirling' —rapid web-borne gyration—when disturbed by ; frequency and duration vary by predator type (most pronounced in response to ). Will abandon webs to invade webs of other spiders and kill them. Rocking behavior (side-to-side body movement) observed as apparent anti-predator response. activity pattern in some .

Ecological Role

of small arthropods in dark, sheltered microhabitats. Intraguild predator capable of subduing larger or more dangerous spider . Contributes to of indoor and cave-dwelling insect .

Human Relevance

are common household inhabitants, particularly in basements, cellars, and window corners. Harmless to humans; bites are rare and not considered medically significant. May provide incidental pest control by capturing small insects indoors. The name 'daddy longlegs' causes persistent confusion with harvestmen (Opiliones) and crane flies (Tipulidae).

Similar Taxa

Holocnemus pluchei (Marbled Cellar Spider)Also a pholcid with long legs and irregular web, but has dome-shaped webs when solitary and exhibits communal web-building ; distinguished by marbled coloration and different abdominal shape.
Opiliones (harvestmen)Share the 'daddy longlegs' and have extremely long legs, but are not spiders (different order); body appears as single oval structure without waist between and .
Tipulidae (crane flies)Share the 'daddy longlegs' in some regions and have long legs, but are insects with single pair of wings; often do not feed and are fragile with easily detached legs.
Other Pholcidae generaMany smaller pholcid share general 'cellar spider' ; distinguished by number (six vs. eight), body size (<4 mm), and structure (presence of furrow or pit).

Misconceptions

The name 'daddy longlegs' is applied to three unrelated groups, causing persistent confusion. Pholcus spiders are sometimes mistakenly considered highly venomous but harmless due to small fangs; this is inaccurate—they are genuinely harmless to humans with weak venom. P. phalangioides has been documented killing dangerous spiders like redbacks, but this does not indicate danger to humans.

More Details

Taxonomic changes

Recent molecular phylogenetic studies (2018) split Pholcus into nine new (Cantikus, Kelabita, Kintaqa, Meraha, Muruta, Paiwana, Pribumia, Teranga, Tissahamia) and synonymized Sihala with Pholcus, reducing count from 393 to 328 species in 21 species-groups.

Defensive behavior research

P. ancoralis exhibits -specific whirling responses: trigger whirling in 50% of trials (average duration 853 seconds), skinks in 20% (455 seconds), and jumping spiders in only 10% (20 seconds), suggesting adaptive tuning of defense to threat level.