Oecobius navus

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Current valid name

Oecobius navus Blackwall (family Oecobiidae)

Recognition and diagnostic features

Very small spider, holds its legs close to its body in a characteristic manner (see photos), and runs at a very fast pace with a convoluted path.

Related or similar species

Dictyna calcarata

Spider

Body lengths when mature: male: 2.58 mm, female: 2.91 mm

Immatures resemble miniature adults.

Egg sac

Description: small circular sac, clutch of few eggs in middle covered very sparsely by a few strands of silk, usually laid in the hollow of a branch or depression

Number of eggs per sac: 10.6 ± 2.18

Size of egg: 0.55 ± 0.023 mm

Time of year eggs are likely to be laid: April to September

Distribution

In California: ubiquitous

Elsewhere: cosmopolitan worldwide including Australia and New Zealand

Not native to North America

This species has been transported and become established outside of its range.

Biology

Makes small webs. Movement is rather fast and in a very convoluted pathway. Often feed on ants. If it runs into an ant, the spider switches from convoluted running to running tight circles around their prey, tying it down with silk as it encircles it. Very dominant non-native spider in agroecosystem leaf litter.

Status in table grapes

Level of Incidence: common

Level of Concern in New Zealand: WPNZ (May 2010) nr, BORIC (Dec 2011) nr, MAF-BPRA (2002) nr (coding definition)

Level of Concern in Australia: WPAU (2006) nr (coding definition)

Level of Medical importance: none

Common name

None for species, flatmesh weavers for family

Taxonomic history

Until recently, it was known from many countries as Oecobius annulipes.

Commonly encountered synonyms

Oecobius annulipes

Selected references

Miyashita, K. 1992. Life cycle of Oecobius annulipes Lucas (Araneae: Oecobiidae) under indoor conditions and the effect of photoperiod on nymphal development. Acta Arachnol. 41: 5-10.

Shear, W. A. 1970. The spider family Oecobiidae in North America, Mexico, and the West Indies. Bull. Mus. Comp. Zool. 140: 129-164.