Spined micrathena (Micrathena gracilis)
The spined micrathena is a spider in the family Araneidae that is not dangerous to people. GBIF holds 2,140 licensed U.S. records of it; it reaches our listing threshold in 32 states, most of all Virginia (263), Pennsylvania (187) and Maryland (183). Its observation records peak in August.
Micrathena gracilis is a spider in the family Araneidae (orb-weavers), commonly known as the spined micrathena or castleback orbweaver. This spider spins a moderately large (can be about 20 cm long in diameter) and very tightly coiled web. The spiders themselves are small and can be found to be anywhere from 4.2 mm to 10.8 mm long.
From Wikipedia: Spined micrathena, text under CC BY-SA 4.0.
Is the spined micrathena poisonous or venomous?
Not in any medically significant way. Like almost all spiders the spined micrathena (family Araneidae) has venom for its prey, but it is not a widow or recluse, the two U.S. groups whose bites need medical attention.
Which states have the spined micrathena?
Records are spread over 32 states; the top three, Virginia, Pennsylvania and Maryland, hold 30% of them.
| # | State | Records | Share of state spiders | Rank in state |
|---|---|---|---|---|
| 1 | Virginia | 263 | 2.3% | 11th of 176 |
| 2 | Pennsylvania | 187 | 2.5% | 5th of 164 |
| 3 | Maryland | 183 | 3.2% | 6th of 153 |
| 4 | Ohio | 179 | 2.6% | 8th of 332 |
| 5 | New York | 163 | 2.6% | 9th of 149 |
| 6 | North Carolina | 133 | 1.6% | 11th of 184 |
| 7 | Indiana | 124 | 2.8% | 6th of 133 |
| 8 | Illinois | 98 | 0.5% | 33rd of 243 |
| 9 | Tennessee | 67 | 1.8% | 13th of 138 |
| 10 | Georgia | 64 | 1.0% | 24th of 186 |
| 11 | Massachusetts | 62 | 1.3% | 19th of 189 |
| 12 | Missouri | 56 | 2.4% | 8th of 117 |
| 13 | New Jersey | 56 | 2.5% | 8th of 127 |
| 14 | Texas | 52 | 0.2% | 100th of 386 |
| 15 | Delaware | 46 | 2.2% | 12th of 71 |
| 16 | Michigan | 46 | 1.9% | 12th of 122 |
| 17 | Alabama | 42 | 1.2% | 17th of 143 |
| 18 | Kansas | 38 | 2.3% | 5th of 94 |
| 19 | Kentucky | 35 | 1.9% | 13th of 103 |
| 20 | Oklahoma | 34 | 0.7% | 35th of 149 |
| 21 | Arkansas | 30 | 1.8% | 14th of 114 |
| 22 | South Carolina | 30 | 1.3% | 20th of 121 |
| 23 | Connecticut | 28 | 2.8% | 10th of 86 |
| 24 | West Virginia | 25 | 3.3% | 6th of 90 |
| 25 | Louisiana | 23 | 0.6% | 37th of 107 |
| 26 | Florida | 16 | 0.1% | 109th of 237 |
| 27 | Wisconsin | 16 | 0.5% | 50th of 149 |
| 28 | Nebraska | 14 | 1.1% | 18th of 71 |
| 29 | Iowa | 13 | 1.9% | 9th of 57 |
| 30 | Mississippi | 9 | 0.6% | 31st of 117 |
| 31 | Minnesota | 4 | 0.1% | 90th of 145 |
| 32 | Rhode Island | 2 | 1.2% | 21st of 53 |
When is the spined micrathena seen?
Across the U.S., observation records of the spined micrathena run mostly July through September, peaking in August with 42% of them. Almost none are from December to February.
Season by state
Among states whose main season falls within one calendar year, it starts earliest in May (Alabama) and latest in July (Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan and 8 more). The most common peak month is July, shared by Alabama, Indiana, Kansas, Kentucky, Missouri, New Jersey and 5 more.
| State | Main season | Peak month | Observation records |
|---|---|---|---|
| Virginia | July through September | August | 262 |
| Maryland | July through September | August | 183 |
| Pennsylvania | July through September | August | 182 |
| Ohio | July through September | August | 179 |
| New York | July through September | August | 163 |
| North Carolina | July through September | July | 129 |
| Indiana | July through September | July | 119 |
| Illinois | July through September | August | 79 |
| Tennessee | June through September | July | 65 |
| Georgia | June through September | August | 64 |
| Massachusetts | concentrated in July and August | — | 62 |
| New Jersey | July through September | July | 56 |
| Missouri | July through September | July | 48 |
| Delaware | July through September | August | 46 |
| Texas | June through November | July | 46 |
| Michigan | July through September | August | 45 |
| Alabama | May through September | July | 42 |
| Kansas | June through September | July | 37 |
| Kentucky | July through September | July | 35 |
| Oklahoma | July through September | July | 32 |
| South Carolina | June through October | July | 30 |
Where the spined micrathena is recorded in each state
Virginia
Virginia holds 263 licensed records, the 11th most recorded of 176 spiders listed there. Its observation records in Virginia run mostly July through September, peaking in August; most licensed records come from Fairfax County, Prince William County and Loudoun County. Next come Albemarle County (10) and Goochland County (10).
Pennsylvania
Pennsylvania holds 187 licensed records, the joint 5th most recorded of 164 spiders listed there. Its observation records in Pennsylvania run mostly July through September, peaking in August; most licensed records come from Allegheny County, Philadelphia County and Berks County. Next come Bucks County (12) and Lancaster County (11).
Maryland
Maryland holds 183 licensed records, the 6th most recorded of 153 spiders listed there. Its observation records in Maryland run mostly July through September, peaking in August; most licensed records come from Montgomery County, Baltimore County and Anne Arundel County. Next come Prince George's County (22) and Frederick County (19).
Ohio
Ohio holds 179 licensed records, the 8th most recorded of 332 spiders listed there. Its observation records in Ohio run mostly July through September, peaking in August; most licensed records come from Franklin County, Summit County and Hamilton County. Next come Montgomery County (12) and Richland County (11).
New York
New York holds 163 licensed records, the 9th most recorded of 149 spiders listed there. Its observation records in New York run mostly July through September, peaking in August; most licensed records come from Rockland County, Tompkins County and Richmond County. Next come Suffolk County (17) and Westchester County (13).
North Carolina
North Carolina holds 133 licensed records, the 11th most recorded of 184 spiders listed there. Its observation records in North Carolina run mostly July through September, peaking in July; most licensed records come from Orange County, Durham County and Mecklenburg County. Next come Wake County (10) and Buncombe County (6).
Indiana
Indiana holds 124 licensed records, the 6th most recorded of 133 spiders listed there. Its observation records in Indiana run mostly July through September, peaking in July; most licensed records come from Monroe County, Morgan County and Marion County. Next come Tippecanoe County (10) and Porter County (8).
Illinois
Illinois holds 98 licensed records, the 33rd most recorded of 243 spiders listed there. Its observation records in Illinois run mostly July through September, peaking in August; most licensed records come from Cook County, Champaign County and DuPage County. Next come Peoria County (6) and Kankakee County (4).
Tennessee
Tennessee holds 67 licensed records, the 13th most recorded of 138 spiders listed there. Its observation records in Tennessee run mostly June through September, peaking in July; most licensed records come from Knox County, Lincoln County and Sevier County. Next come Montgomery County (7) and Blount County (6).
Georgia
Georgia holds 64 licensed records, the joint 24th most recorded of 186 spiders listed there. Its observation records in Georgia run mostly June through September, peaking in August; most licensed records come from DeKalb County, Oconee County and Clarke County. Next come Cobb County (4) and Newton County (3).
Massachusetts
Massachusetts holds 62 licensed records, the 19th most recorded of 189 spiders listed there. Its observation records in Massachusetts are concentrated in July and August (90% of them); most licensed records come from Barnstable County, Hampden County and Middlesex County. Next come Norfolk County (8) and Worcester County (7).
Missouri
Missouri holds 56 licensed records, the 8th most recorded of 117 spiders listed there. Its observation records in Missouri run mostly July through September, peaking in July; most licensed records come from Platte County, Texas County and Jackson County. Next come St. Louis County (4) and Christian County (3).
New Jersey
New Jersey holds 56 licensed records, the 8th most recorded of 127 spiders listed there. Its observation records in New Jersey run mostly July through September, peaking in July; most licensed records come from Middlesex County, Atlantic County and Hunterdon County. Next come Mercer County (5) and Morris County (4).
Texas
Texas holds 52 licensed records, the 100th most recorded of 386 spiders listed there. Its observation records in Texas run mostly June through November, peaking in July; most licensed records come from Harrison County, Jasper County and Cameron County. Next come Smith County (3) and Dallas County (3).
Delaware
Delaware holds 46 licensed records, the 12th most recorded of 71 spiders listed there. Its observation records in Delaware run mostly July through September, peaking in August; most licensed records come from Sussex County, Kent County and New Castle County.
Michigan
Michigan holds 46 licensed records, the joint 12th most recorded of 122 spiders listed there. Its observation records in Michigan run mostly July through September, peaking in August; most licensed records come from Washtenaw County, Ingham County and Oakland County. Next come Kalamazoo County (4) and Allegan County (4).
Alabama
Alabama holds 42 licensed records, the joint 17th most recorded of 143 spiders listed there. Its observation records in Alabama run mostly May through September, peaking in July; most licensed records come from Mobile County, Blount County and Cullman County. Next come Jefferson County (2) and Marshall County (2).
Kansas
Kansas holds 38 licensed records, the joint 5th most recorded of 94 spiders listed there. Its observation records in Kansas run mostly June through September, peaking in July; most licensed records come from Leavenworth County, Douglas County and Johnson County. Next come Linn County (2) and Morris County (2).
Kentucky
Kentucky holds 35 licensed records, the 13th most recorded of 103 spiders listed there. Its observation records in Kentucky run mostly July through September, peaking in July; most licensed records come from Madison County, Fayette County and Estill County. Next come Kenton County (2) and Boone County (2).
Oklahoma
Oklahoma holds 34 licensed records, the 35th most recorded of 149 spiders listed there. Its observation records in Oklahoma run mostly July through September, peaking in July; most licensed records come from Mayes County, Cleveland County and Pawnee County. Next come Comanche County (2) and Oklahoma County (2).
Arkansas
Arkansas holds 30 licensed records, the joint 14th most recorded of 114 spiders listed there. Most of its licensed records in Arkansas come from Craighead County, Poinsett County and Washington County. Next come Clay County (2) and Perry County (2).
South Carolina
South Carolina holds 30 licensed records, the joint 20th most recorded of 121 spiders listed there. Its observation records in South Carolina run mostly June through October, peaking in July; most licensed records come from Richland County, Greenville County and Oconee County. Next come Charleston County (3) and Spartanburg County (3).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Fairfax County | Virginia | 100 | 4.7% |
| 2 | Montgomery County | Maryland | 46 | 2.1% |
| 3 | Sussex County | Delaware | 40 | 1.9% |
| 4 | Baltimore County | Maryland | 27 | 1.3% |
| 5 | Orange County | North Carolina | 26 | 1.2% |
| 6 | Cook County | Illinois | 24 | 1.1% |
| 7 | Anne Arundel County | Maryland | 24 | 1.1% |
| 8 | Prince George's County | Maryland | 22 | 1.0% |
| 9 | Allegheny County | Pennsylvania | 22 | 1.0% |
| 10 | Rockland County | New York | 21 | 1.0% |
| 11 | Franklin County | Ohio | 20 | 0.9% |
| 12 | Frederick County | Maryland | 19 | 0.9% |
| 13 | Tompkins County | New York | 19 | 0.9% |
| 14 | Prince William County | Virginia | 19 | 0.9% |
| 15 | Richmond County | New York | 17 | 0.8% |
How recent are the spined micrathena records?
Most of what is known about the spined micrathena is recent: 93% of dated U.S. records were made in 2017–2026, and half date from 2022 or later. The oldest dated record is from 1928; the busiest year was 2025, with 299 records.
| Decade | Records | Share |
|---|---|---|
| 1920s | 1 | 0.0% |
| 1930s | 1 | 0.0% |
| 1940s | 1 | 0.0% |
| 1950s | 3 | 0.1% |
| 1960s | 2 | 0.1% |
| 1970s | 9 | 0.4% |
| 1980s | 14 | 0.6% |
| 1990s | 3 | 0.1% |
| 2000s | 12 | 0.5% |
| 2010s | 448 | 20.3% |
| 2020s | 1,712 | 77.6% |
Species recorded in the same counties
Of the 301 counties where the spined micrathena is most recorded, 184 are also top counties for the orchard orbweaver, more than for any other spider. None of its closest neighbors is venomous.
| Species | Shared counties |
|---|---|
| Orchard orbweaver | 184 |
| Familiar jumping spider | 183 |
| Nursery web spider | 182 |
| Spotted orbweaver | 178 |
| Black-and-yellow argiope | 167 |
| Bold jumper | 167 |
| Dark fishing spider | 157 |
| Paraphidippus aurantius | 138 |
Related species in the U.S.
Other members of the family Araneidae with profiles here: Black-and-yellow argiope, Spotted orbweaver, Spiny-backed orbweaver, Garden spider, American golden orb weaver and Banded garden spider.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.