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.

Adult_Female_Black_Widow
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 oblonged 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.

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

Size

The adult female Southern black widow reaches a body size of around 0.5 inches (around 10mm). 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.

Web

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 widoes 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, vomitin 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.

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

Leave a Reply

Your email address will not be published. Required fields are marked *


The maximum upload file size: 15 MB.
You can upload: image.

Scroll to top