The arrow-shaped orb weaver, Micrathena sagittata, is a strange-looking, arrow-shaped spider that is commonly found in gardens of the Eastern United States. The spider’s abdomen is large and yellow with two large red and black spines on its back. Its specific name “sagittata” is Latin for “arrowed” and it refers to the shape of the abdomen.
Arrow-Shaped Orbweaver Description
Arrow-shaped micrathena spiders are quite easy to identify. Their abdomens are arrow-shaped, as the common name suggests.
The female spiders have striking reddish, black, and yellow colors. They have a pair of large tubercles at the back end of their abdomen that point outward and forms an arrow-shaped body. With a deeper look into such spiders, they form their shapes almost like a colorful “Flying V” electric guitar. The cephalothorax (head) and legs are usually brown or orange.
The ventral side of the spider (underside) is mostly black with red and yellow markings.
The males don’t have any spines on their abdomen but since they are only half the size of the female, they are rarely seen.
Size
Micrathena spiders relatively small spiders. The larger female spiders can grow up to 0.35 in. (9 mm) in body length. Male individuals are usually only around half the size of females and reach a maximum body length of 0.2 in. (5 mm).
Web
The arrow-shaped micrathena are part of the orb weaver family. These spiders typically spin a large elaborate wheel-shaped flat web. The females spin intricate, circular webs and they mostly rest in their webs. This family of spiders aims at spinning the webs at face-level to catch flying bugs.
Bite
The arrow-shaped micrathena spiders aren’t dangerous to people to all. These spiders only use their venom to paralyze and kill bugs, other than that, their venom isn’t strong enough to do the same to humans. A bite, which happens very rarely, would normally only cause mild symptoms such as swelling or local pain.
Distribution of the arrow-shaped orb weaver in the United States
The arrow-shaped micrathena is a common spider in the Eastern United States. More specifically, they are found in the following states: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Vermont, Virginia, West Virginia and Wisconsin.
Micrathena sagittata scientific classification
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Araneidae
- Genus: Micrathena
- Species: Micrathena sagittata
References
- Taxon details: World Spider Catalogue
- Binomial name from: Walckenaer, 1841
- Missouri Department of Conservation
- Kaston, B. J. (1978). How to Know the Spiders. WCB/McGraw-Hill. ISBN 0-697-04898-5.
NW PA, about a half inch long if that.
Hello Ben, thanks for uploading this great find. This is a spined orb weaver. Most likely a male Micrathena sagittata: https://spiderid.com/picture/2080/
You can read more about it here: https://usaspiders.com/micrathena-sagittata-arrow-shaped-orbweaver/
“The dorsal side of the spider (underside) is mostly black with red and yellow markings.”
Don’t you mean, the “ventral” side?
Hello Nancy, I most certainly did 🙂 Thanks for pointing that out. The head must have been somewhere else while typing. It’s corrected now but could take a few days to actually show up due to caching on the internet. Thank you!
Thank You for helping me to identify this Strange looking spider, Arrow shaped Orbweaver. At first I thought it had wings because of its arrow shaped back end. One weird spider.
Got a picture of one of these unusual looking spiders outside my window in NC. Not very big (especially compared to the Agelenopsis specimens that have taken up residence in the car port), but very distinct, and with a lovely web!