Euryopis tavara
Levi, 1954
Euryopis tavara is a small cobweb spider in the Theridiidae, Hadrotarsinae. Unlike most theridiids, it does not construct prey-catching webs. The is known from the United States and shares the -wide trait of specialized . It is one of approximately twenty Euryopis species recorded in North America north of Mexico.
Pronunciation
How to pronounce Euryopis tavara: /ˌɛəriˈoʊpɪs təˈvɑːrə/
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Identification
Distinguished from other theridiids by the combination of: high nearly as wide as long; exceptionally long, flat fangs; sub-triangular with bold patterning; absence of prey-catching web; and -hunting . Separated from other Euryopis by subtle morphological differences, particularly in female genitalia anatomy, requiring expert examination.
Appearance
Very small spider with body length likely between 1.3–4.7 mm based on characteristics. The has a sub-triangular shape with bold color patterning. The is high and nearly as wide as it is long. Both sexes possess exceptionally long, flat fangs.
Habitat
Found in upper elevation watershed areas (observed at 8,500–9,000 feet in Colorado). Occurs on ground, foliage, and tree trunks. Associated with areas of high traffic and near ant mounds.
Distribution
United States. Specific state records include Colorado.
Seasonality
have been observed in late June. Activity likely coincides with periods of high foraging.
Diet
Ants. The Euryopis is known for specialized ; at least one congeneric feeds almost exclusively on harvester ants (Pogonomyrmex).
Life Cycle
Females produce white, hemispherical sacs covered in tufts of silk. Egg sac size is notably large relative to the small body size of the female.
Behavior
An ambush that does not spin prey-catching webs. Sits with legs outstretched on substrate and waits for ants to make contact. Upon contact, rapidly circles the while flinging silk to bond it to the substrate. Bites immobilized prey, typically on a leg joint, then constructs a silk sling to transport the victim to a secure feeding location.
Ecological Role
of ants, including aggressive such as harvester ants. Represents a specialized predator-prey relationship uncommon among spiders.
Human Relevance
None documented. Easily overlooked due to small size and cryptic appearance. Occasionally encountered by naturalists and biologists during field surveys.
Similar Taxa
- Other TheridiidaeMost theridiids construct tangled cobwebs for prey capture; Euryopis lacks this and has morphological differences including high and long flat fangs.
- Other Euryopis speciesApproximately twenty in North America; separation requires examination of female genitalia and other subtle morphological characters.
More Details
Taxonomic Placement
Placed in Hadrotarsinae based on shared characters: high nearly as wide as long, exceptionally long flat fangs, female genitalia anatomy, and absence of prey-catching webs.
Research History
described by Levi in 1954. The specialized -hunting of the was documented by Porter and Eastmond (1981) for congeneric E. coki.