Pityohyphantes costatus

(Hentz, 1850)

hammock spider

Pityohyphantes costatus, commonly known as the hammock , is a sheetweb weaver in the Linyphiidae. The name derives from its distinctive web architecture, which resembles a suspended hammock. It occurs primarily in coniferous forests of North America, though it has also been found in hardwood . The name translates from Greek as 'pine weaver,' reflecting its association with coniferous vegetation.

Common Spiders U.S. 333-4 Pityohyphantes costatus by James Henry Emerton (1847 – 1931). Used under a Public domain license.

Common Spiders U.S. 332 Pityohyphantes costatus by James Henry Emerton (1847 – 1931). Used under a Public domain license.

Pronunciation

How to pronounce Pityohyphantes costatus: /ˌpɪti.aɪˈfænˌtiːz kɔˈstætəs/

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Identification

Reliable identification requires examination of external . Distinguished from cobweb weavers (Theridiidae) by presence of prominent on legs; cobweb weavers have -free legs. The web structure also differs: hammock build slightly convex sheet platforms suspended by a maze of threads above, while cobweb weavers construct irregular three-dimensional tangles. The abdominal pattern is consistent across the but not diagnostic to species level without genital examination.

Images

Appearance

Small with mature females measuring 5-7 millimeters in body length; males slightly smaller. The displays a consistent and distinctive pattern: a or reddish jagged-edged longitudinal on an ivory or pale background. Legs bear prominent (), a characteristic feature distinguishing sheetweb weavers from cobweb weavers.

Habitat

Primarily coniferous forests, particularly pine-dominated , though also occurs in hardwood forests. Webs are constructed in foliage well above ground level, on fences, or on exterior surfaces of buildings and other manmade structures. typically position themselves on the underside of peripheral foliage rather than hanging in the web center.

Distribution

North America; recorded from United States and Canada (Alberta). Most in occur in western and northern coniferous forests; P. costatus specifically documented from western Massachusetts and Colorado Range.

Seasonality

Mating occurs in spring. and immatures may overwinter under bark or stones on the ground.

Diet

, likely small that fall from branches above the web onto the sheet platform.

Life Cycle

Mating takes place in spring. Female attaches sac to twig or other object at web periphery. Both and immatures may winter under bark or ground stones.

Behavior

Constructs slightly convex sheetweb suspended by maze of threads above the platform; web does not typically sag into a true hammock shape. hangs upside down beneath sheet. Usually conceals itself on underside of peripheral foliage rather than occupying web center. Mature males abandon web-building to wander in search of mates and do not feed during this period.

Ecological Role

of small ; contributes to dynamics in forest .

Human Relevance

Occasionally found on building exteriors and fences; harmless to humans due to small size.

Similar Taxa

Theridiidae (cobweb weavers)Similar web-building habit but distinguished by -free legs and irregular three-dimensional web architecture versus prominent leg and sheet platform with supporting threads in Pityohyphantes
Other Linyphiidae (sheetweb weavers)Web architecture differs: bowl and doily (Frontinella pyramitela) build distinct dome and sheet combination; dome spiders construct different web geometries

Misconceptions

Despite the 'hammock ,' the web is typically slightly convex rather than concave like a true hammock. The spider does not rest in the web center for relaxation but uses it as a -capture platform.

More Details

Etymology

name Pityohyphantes derives from Greek 'pitys' (pine) + 'hyphantes' (weaver), referencing association with coniferous forests. 'hammock ' refers to web's suspended, sheet-like appearance.

Subspecies

Two recognized: Pityohyphantes costatus costatus (Hentz, 1850) and Pityohyphantes costatus annulipes (Banks, 1892)