Pronunciation
lat"ro-dek't[schwa]s var·E·O·lus
Size
Adult Female: approximately 9-11 mm (just under 1/2 inch) in body length (not including legs)
Adult Male: approximately half the size of the female, around 4-5 mm (just under 1/4 inch) in body length (not including legs)
Identification
Females: The range of the L. variolus significantly overlaps the range of the L. mactans, but the female Northen Black Widow often can be distinguished from the female Southern Black Widow by the type of hourglass marking on the ventral portion of the abdomen. For the Northern Black Widow, the hourglass is distinct, but is broken
(1) (whereas the
Southern Black Widow's hourglass is complete) and typically there is a row of red spots down the middle of the back and possibly some diagonal whitish bands on each side; the bands are typically observed on the younger, more juvenile widows.
Males and Immatures: Males and immatures have four diagonal whitish bands on each side of the abdomen. The egg sac from which the spiderlings will emerge is a brown and paper-like.
Although the Northern Black Widow is slightly smaller and not "quite as venomous/dangerous" (definitely still not to be messed with), it is similar to the Southern Black Widow (
L. mactans) in general behaviors. Please refer to L. mactans
info page and the Latrodectus genus
info page for more information.
Web:
The web is typically a 3-dimensional, unorganized mass of silk spun in a dark crevice or corner. The web is sticky, and very strong. If the web is active (in use), the female will be in or very near the web.
Range
The Northern Black Widow is typically considered an "East Coast" spider, it occurs from northern Florida to south-eastern Canada. This species is most common in the northern part of its range.
Habitat
Undisturbed woods, in stumps, or in stone walls.
Remarks
Caution: This spider is venomous and can harm people. However, the female injects such a small dose of venom that it rarely causes death. Reports indicate human mortality at well less than 1% from black widow spider bites. (Net Ref
(1))
While Latrodectus variolus is not aggressive and does not have the instinct to bite, her venom is neurotoxic, which means that it blocks the transmission of nervous impulses. If the spider bites, most likely it has been pressed against human bare skin, and this causes a natural reaction, a bite in self-defense. For the most part, the black widow's bite may be felt only as a pin prick, during which the spider's fangs inject a minute amount of highly toxic venom under the skin. The severity of the victim's reaction depends on his or her age and health, and on the area of the body that is bitten. Local swelling and redness at the site may be followed in one to three hours by intense spasmodic pain, which can travel throughout the affected limbs and body, settling in the abdomen and back (intense abdominal cramping, described as similar to appendicitis), and can last 48 hours or longer. Elderly patients or young children run a higher risk of severe reactions, but it is rare for bites to result in death; only sixty-three having been reported in the United States between 1950 and 1959 (Miller, 1992). Other symptoms can include nausea and profuse perspiration. If left untreated, tremors, convulsions and unconsciousness may result. When death does occur, it is due to suffocation.
For more general information about the Widow spider, please refer to the Latrodectus genus info page.
If you are bitten by a widow spp. spider:
Contact your physician, hospital or poison center immediately and follow their instructions. Poison Centers across the country now have a new national emergency phone number - 1-800-222-1222.
Collect the spider if possible for identification. Your physician may administer an antivenom treatment and calcium gluconate to alleviate pain, and will probably treat the site with antiseptic to prevent infection.
If you have a heart condition or are otherwise vulnerable, you may require a hospital stay until symptoms subside. Usually bite victims recover fully within two to five days.
Precautions:
Be very careful when working around areas where widow spiders may be established. Take proper precautions-wear gloves and pay attention to where you are working. The reaction to a widow bite can be painful, and the victim should go to the doctor immediately for treatment.
See Also
Genus of False Widows (
Steatoda):
info
Specific Species of False Widow (
Steatoda grossa):
infoInternet References
1)
Ohio State University Extension: Fact Sheet on Northern Black Widows
2)
Montana State University Extension Service: A general guide to various spiders found within Montana, including the Northern and Western Black Widow.
