Micrathena Sagittata – Arrow-Shaped Orbweaver

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.

Micrathena Sagittata - Arrow-Shaped Orbweaver information
A female arrow-shaped orbweaver. Photo: Judy Gallagher

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 dorsal side of the spider (underside) is mostly black with red and yellow markings.

Dorsal view of a Micrathena Sagittata - Arrow-Shaped Orbweaver - Photo from below spider in web
The underside of an arrow shaped orbweaver is mostly black with yellow markings. Photo: Judy Gallagher

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.

Brown, orange, yellow spider in web with black spines - Micrathena Sagittata - Arrow-Shaped Orbweaver
A joung Micrathena sagittata with prey in its web. Photo: Judy Gallagher

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

Micrathena Sagittata – Arrow-Shaped Orbweaver

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