Latrodectus Mactans – Southern Black Widow

Latrodectus mactans - Southern black widow

Latrodectus mactans, the Southern black widow is a close relative of the Northern black widow and the Western black widow. The female of all three species is mostly black with a distinctive red hourglass pattern on the underside of its abdomen. They can inject a potent venom with their bite with potential severe medical effects.

Description of the Southern Black Widow

The body of the adult female Southern black widow is completely black apart from the characteristic red hourglass shape on the lower side of its abdomen and a red dot on its backside. The two parts of the hourglass shape of the Southern widow are connected while the hourglass of the Northern black widow that occurs in the same range is often divided into two triangles.

The underside of a female Southern Black Widow showing the connected red hourglass pattern. Photo: Wikipedia

The female, male, and juvenile spiders all look different. The male has an oblong abdomen with yellow, white, red or orange markings on it. While the male spider also carries venom, it is not able to deliver a medically significant bite to humans or larger pets. The same goes for juvenile female spiders.

Latrodectus mactans Southern black widow female closeup high resolution dorsal below
Here is a great shot of the underside of a southern black widow showing the hourglass shape. Photo used with permission from Chase Noble.

Adult females are often confused with the similar-looking false black widow (Steatoda grossa).


The adult female Southern black widow reaches a body size of around 0.5 inches (around 10 mm). With extended legs, it can reach about three times that size. The male is only about half the size of the female.

Latrodectus mactans - Southern black widow
A gravid adult female Southern black widow.


All species of the widow spiders in the United States don’t build properly shaped webs. Their webs are mostly disorderly patches of web built in corners or other edges. The silk itself is sticky and captures prey that happens to run by. The spider will then rush to the helpless prey and deliver a lethal bite.

Southern Black Widow Bite

Only the bites of the adult female Southern black widow poses a potential threat to humans and pets. Male black widows as well as juvenile females do not have the potency to cause serious medical issues.

However, if you have been bitten by a black widow, head to the nearest hospital or doctor immediately. If possible, capture the spider that has bitten you and bring it with you. This will help medical staff to determine the potential venom. A bite of a female Southern black widow may only feel like a mild bee sting at first. However, as the strong neurotoxin takes effect, symptoms such as chest pain, tremors, labored breathing, nausea, profuse perspiration, vomiting and a weak pulse my set in.

Range of the Southern Black Widow in the United States

Southern Black Widow Geographic Distribution Map
The range of the Southern Black Widow in the United States.

The Southern Black Widow can be found throughout the Southeastern states of the US. These are the following: Texas, Oklahoma, Louisiana, Arkansas, Missouri, Illinois, Mississippi, Tennessee, Kentucky, Ohio, Alabama, Florida, Georgia, South Carolina, North Carolina, Virginia, Maryland, Delaware, New Jersey as well as in Southern West Virginia.

Scientific Classification of Latrodectus mactans

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Chelicerata
  • Class: Arachnida
  • Order: Araneae
  • Infraorder: Araneomorphae
  • Family: Theridiidae
  • Genus: Latrodectus
  • Species: Latrodectus mactans
Latrodectus Mactans – Southern Black Widow

9 thoughts on “Latrodectus Mactans – Southern Black Widow

  1. This spider was found in Woodlawn TN. It resembles the redback spider native to Australia. But there are no reports that this spider is in the US. I did compare it it the normal black widow spider, but this one has a red stripe on top of the abdomen! Please help!

    1. Hello Lindsey, thanks for getting in touch! This is definitely a black widow (either Latrodectus variolus or Latrodectus mactans). They start off with several white and red patterns on their back as juveniles and slowly lose the colors on the back. This one is a female black widow.

  2. Woodsfield, Ohio

    Caught my eye on a gas well, while working on the pad.

    I believe female southern black widow.

    She was getting ready for a wooly worm, meal.

    1. Hi Danna, this is a male black widow. Your location would help to narrow down the exact species. It’s best to handle that one with care, but generally male black widows and juvenile female black widows are not considered medically significant.

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