Euryopis mulaiki
Levi, 1954
Euryopis mulaiki is a minute cobweb (Theridiidae) in the Hadrotarsinae, distinguished by its unusual hunting . Unlike web-building relatives, this is an active that immobilizes by flinging rather than constructing capture webs. are exceptionally small, with body lengths of 1.3–4.7 mm, and exhibit a characteristic sub-triangular abdominal shape with bold color patterns. The species was described by Levi in 1954 and occurs in the southwestern United States and Mexico.
Pronunciation
How to pronounce Euryopis mulaiki: /ˌjʊrɪˈəʊpɪs mjuˈlaɪki/
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Identification
Euryopis mulaiki can be distinguished from other small theridiids by its high, nearly equilateral and long, flat —traits of the Hadrotarsinae. The sub-triangular with bold patterning separates it from most other Euryopis , though species-level identification requires examination of female . Unlike typical theridiids, it is never found in webs. It may be confused with linyphiids or other ground-dwelling micro-, but the combination of abdominal shape, bold patterning, and -associated is distinctive for the .
Habitat
Found in upper elevation watersheds (observed at 8,500–9,000 feet in Colorado), typically on ground, foliage, or tree trunks in areas with high traffic. Often associated with ant mounds and places where ants are abundant. In captivity, constructs simple retreats for sac deposition.
Distribution
Recorded from the southwestern United States (Colorado, New Mexico) and Mexico. GBIF records indicate presence in Middle America and North America.
Seasonality
have been observed in June in Colorado; general activity period likely spans warmer months when are active. Specific otherwise undocumented.
Diet
Specialized ; has been observed preying on (). Uses unique -flinging technique to immobilize ants before envenomation.
Life Cycle
Females produce , hemispherical sacs covered in tufts of ; sac size is surprisingly large relative to maternal body size. Spiderlings emerge from egg sacs but early development undocumented.
Behavior
An active hunter that does not construct -capture webs. Adopts ambush posture with legs outstretched, waiting for to make contact. Upon tactile stimulation, rapidly circles the ant while discharging from to bond the prey to the substrate. Bites immobilized ant, typically at leg joint, then constructs silk 'sling' to transport victim to sheltered feeding site.
Ecological Role
Specialized of , including aggressive such as ; represents a rare case of dedicated ant among . May help regulate local ant in high-elevation .
Human Relevance
Non-pest; as . Occasionally encountered indoors. Not medically significant given minute size.
Similar Taxa
- Other Euryopis speciesShare sub-triangular and -hunting , but differ in color pattern and genitalic anatomy; E. mulaiki distinguished by specific abdominal markings and geographic range
- Theridiidae (typical cobweb spiders)Construct tangled -capture webs and have rounded ; Euryopis lacks web-building and has distinctive high
- Linyphiidae (sheet-web weavers)Similar small size and ground-dwelling habit, but build sheet webs and lack bold abdominal patterning and -flinging predatory
More Details
Taxonomic placement
Placement in Hadrotarsinae based on structure, , female anatomy, and absence of -capture web construction—traits that distinguish the from other theridiids
Conservation of hunting technique
The -flinging ambush strategy appears conserved across Euryopis , representing a remarkable evolutionary departure from the web-building typical of Theridiidae