Identification
Identification information from Levi, 1977.
(1)
M. arizonica, Females 4.7 to 8.4 mm, Males 2.7 to 3.8 mm - like M. crassipes (unlike M. grinnelli and gosoga) the carapace is very dark brownish black except for the light transverse anterior head region. (two white ventral marks & 2 spots above spinnerets)
M. comanche, Males vary greatly in size. - Anterior light area of head grades gradually into dark area posteriorly. A median light streak in many specimens just anterior to thoracic depression. Legs banded. Venter often with white transverse bar connecting with longitudinal mark. There is one spot on each side, anterior to the spinnerets.
M. crassipes, Females 4.9 to 7.2 mm, Males 2.9 to 4.7 mm - The white sternal band may be broken as in grinnelli. This species is smaller than grinnelli. Females can be confused with arizonica, males are more often confused with ventura. Ventral view has both abdominal vertical white band & sternal vertical white band.
M. datona - Unlike other North American species, it has an abdomen that is wider and more spherical than it is long, and the anterior of the dorsum has a light patch framed by black. It has the ventral median longitudinal white stripe on the abdomen.
M. foxi, Females 3.6 to 6.1 mm, Males 2.7 to 4.5 mm - Metepeira foxi differs from all other species north of Mexico, except grandiosa and datona by not having a white longitudinal line on the sternum. It doesn't occur in Florida like datona.
M. gosoga, Females 7.5 to 9.4 mm, Males 4.4 to 5.5 mm - Light colored carapace having only the posterior head region dark, by the white abdomen. Two adjacent black marks surrounded by white pigment on the venter.
M. grandiosa - 2 subspecies - both have no median longitudinal band on the black sternum. - I don't know if these two are still considered subspecies.
-M. grandiosa alpina - Coxae never black.
-M. grandiosa grandiosa - More variable than the others.
M. labyrinthea - The Spiders of the Eastern US says that the Metepeira labyrinthea can be distinguished from other orbweavers by having longer terminal leg segments "(tarsus plus metatarsus longer than tibia plus patella)". It does have the longitudinal light line on the sternum which isn't found on grandiosa & datona.
M. minima - two white ventral marks.
M. palustris - No median longitudinal band on the black sternum. Black coxae, sometimes yellow coxae or both black and yellow coxae.
M. pimungan - White eye region. White median ventral mark on abdomen flanked by shorter parallel thin lines on either side. Black sternum with white teardrop shaped mark on the posterior half. Legs mostly white with with bands on legs 3 & 4. Spinnerets flanked on each side by one white spot.
M. spinipes, Females 5 to 9.4 mm, Males 3.6 to 6.7 mm - Coloring is pronounced and leg banding is more distinct than the similar labyrinthea. Most species have the ventral white line of the sternum broken by black pigment; sometimes the anterior or posterior part of the line is missing. Grinnelli differs from arizonica in having the posterior head region darker usually than the thorax to the sides.(One or two white ventral marks & 2 spots around spinnerets) M. spinipes is the only species in the genus that lives in colonies. Habitat - Riparian open field, woodland and coastal shrubs.
M. ventura - A median light streak may be present on the carapace and the light sternal band is sometimes broken. The middle of the posterior head region often has a light streak not found in grinnelli, crassipes or arizonica.(two white ventral marks & 2 spots around spinnerets, light "U" mark under the abdominal white mark)
Range
13 species in bugguide's range.
Metepeira labyrinthea MA, CT, NY, NJ, PA, ON, OH, MI, WI, IL, IN, KS, MO, KY, WV, VA, NC, SC, TN, AR, OK, TX, LA, MS, AL, GA, FL
Metepeira grandiosa BC, AB, SK, ND, SD, MT, WY, CO, KS, OK, NM, AZ, UT, ID, OR, NV, WA, CA
Metepeira foxi BC, AB, WA, OR, CA, ID, MT, WY, CO, UT, AZ, NM, TX
Metepeira palustris BC, AB, SK, ON, PQ, WI, MI, PA, NY, ME, NS, ND, SD, MT
Metepeira gosoga CA, NV, AZ, UT
Metepeira arizonica CA, AZ, NM, TX
Metepeira spinipes (syn. grinnelli) OR, CA, AZ
Metepeira comanche NM, TX
Metepeira pimungan Piel, 2001 Endemic on San Miguel Island, Santa Barbara Co., Calif
Only in California: Metepeira ventura and Metepeira crassipes
Only in Florida: Metepeira datona
Only in Texas: Metepeira minima - southern tip
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Five species occur in Texas:
Metepeira arizonica Chamberlin & Ivie, 1942
Metepeira comanche Levi, 1977
Metepeira foxi Gertsch & Ivie, 1936
Metepeira minima Gertsch, 1936 - southern tip
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In the northwest there is only M. grandiosa, M. palustris & M. foxi.
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In the northeast only two species are found: M. palustris & M. labyrinthea.
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CA Species (From Steve Lew's Spider of CA)
M. arizonica - San Diego Co. north to Los Angeles Co,, Imperial Co. north to Inyo Co.
M. crassipes - San Diego Co. north to Sonoma Co., plus Lassen Co.
M. foxi - San Diego Co. north to Los Angeles Co,Imperial Co. north to Siskiyou Co.
M. gosoga - Riverside Co. northwest to Ventura Co., plus Inyo Co., Kern Co., Tulare Co.
M. grandiosa - San Diego Co. north to Siskiyou Co.
M. spinipes - San Diego Co. north to Del Norte Co., plus San Miguel Is.
M. ventura - San Diego Co. north to Sonoma Co., plus Lassen Co., Madera Co., Tulare Co.
Remarks
Metepeira species generally build an orb web with an attached retreat suspended in a tangle web.
In the southwest US,
Diguetia retreats may be confused for
Metepeira retreats. However,
Diguetia retreats will be associated with a cone-shaped sheet web, not an orb web and a tangle web.
M. spinipes also exhibits wide variation in social grouping tendencies, ranging from solitaries and small groups of 2-3 individuals in desert and higher elevation habitats to groups of tens to hundreds in in mesic riparian habitats near lakes in central Mexico (Uetz et al. 1982), and along creeks in coastal areas of central California.
Experimental studies manipulating prey availability and “transplanting” colonies in the field in central Mexico suggest that colonial web-building in M. spinipes is facultative, and that prey availability plays a large role in determining group size, inter-individual spacing within colonies, and life history parameters over the gradient of habitats sampled (Uetz et al. 1982, Benton and Uetz 1986; Uetz et al. 1987).
The colonial orbweaving spiders of Mexico and the southwestern United States build interconnected webs, but they defend their own turf, says Uetz. The longest continuous colony that has been observed was built of orbs knitted together by hundreds of thousands of 1-centimeter-long spiders. It measured 4 m across and 2 m high and stretched nearly two football fields long!!!