Metepeira arizonica
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adult female, live |
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adult female, live, light coloring |
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adult male, live |
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female genitalia; epigynum |
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female genitalia; epigynum, lateral view |
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male genitalia; palp, lateral view |
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male genitalia; palp, ventral view |
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grape size comparison with adult spiders; male (left), female (right) |
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spiderling, live |
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spiderlings, dead; dorsal (left), ventral (right) |
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egg sac |
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egg sac with scale (cm) |
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eggs |
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diagnostic feature; white marking on ventral abdomen |
Current valid name
Metepeira arizonica Chamberlin and Ivie (family Araneidae)
Recognition and diagnostic features
Orb-weaving spider with unique marking on middle of ventral surface of abdomen: a white longitudinal line surrounded by black longitudinal lines, leaf-like pattern on dorsal surface of abdomen.
Related or similar species
Immatures of Neoscona oaxacensis
Spider
Body lengths when mature: male: 2.7 - 3.8 mm, female: 4.7 - 8.4 mm
Immatures resemble miniature adults.
Egg sac
Description: oblong sac suspended in web, often with others in tandem, looks like a seed pod or piece of dead vegetation, eggs are longer than wide (bean-shaped)
Number of eggs per sac: 30.4 (range 18 to 45)
Size of egg: 0.94 ± 0.029 mm for greatest length
Time of year eggs are likely to be laid: late summer
Distribution
In California: southern half of state
Elsewhere: Arizona, southwestern New Mexico, western Texas, Mexico
Native to North America
This species has not been transported or become established outside of its range.
Biology
Orb weaving. Makes retreat of silk and debris a short distance away from the catching orb web where it hides waiting for prey to fall into web. Collected from March to December. Common in citrus in the Central Valley, but not common in grapes.
Status in table grapes
Level of Incidence: uncommon
Level of Concern in New Zealand: WPNZ (May 2010) nr, BORIC (Dec 2011) nr (not listed), 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, orb weavers for family
Taxonomic history
Stable
Selected references
Levi, H. W. 1977. The orb-weaver genera Metepeira, Kaira, and Aculepeira in America north of Mexico (Araneae: Araneidae). Bull. Mus. Comp. Zool. 148: 185-238.
