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Black Widow

Black Widow Facts

Size 0.2-0.6 inches (7.5-16 mm)
Speed Unknown
Weight Unknown
Lifespan Up to 3 years
Food Arthropods, insects
Predators Wasps, birds, small rodents, reptiles
Distribution Europe, America, Asia, Africa, Australia
Habitat Dry, warm, open areas
Order Araneae
Class Cobweb Spiders
Order Arachnids
Scientific name Latrodectus tredecimguttatus
Characteristics Venomous, black cobweb spider with red spots

Main Characteristics

The black widow is a cobweb spider that kills its prey with venom. A bite is not entirely harmless for humans either. Its most eye-catching features are its black, ball-shaped body with red markings on it. It is famous for eating the male after mating.

Black Widow Black Widow - Photo: Jay Ondreicka/Shutterstock

Species

There are over 20 species of widow spiders. Most have red hourglass-shaped markings. However, there are also species that have large red spots. In America, the southern, western and northern black widows are the most common. The European black widow is most common in Europe and Africa. It's also showing up occasionally in Germany now.


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Southern Black Widow Southern Black Widow - Photo: James Gathany [Public Domain], via Wikimedia Commons

Distribution and Habitat

The European black widow prefers dry, warm and open areas with few plants - for example barren grasslands, dunes, sandy and scree beaches. It's most common in the Mediterranean region, but also lives in Ukraine, Caucasus, Russia, Kazakhstan, Iran, Central Asia and China. In America, the northern, southern and western black widow, according to their name, inhabit areas throughout North America. They also live in barren, desolate landscapes, although the southern black widow can also be found in rainforests. There are also some species in Australia and South America.

Life Style

The black widow is a nocturnal animal that lives an solitary life. It spends most of its time on the ground and spins its web in medium-height grass or on overhanging rocks. They are most commonly seen between May and November.

Black Widow Characteristics Black Widow Characteristics - Photo: jwjarrett/stock.adobe.com

Anatomy and Appearance

Size and Weight

The female black widow has a body length of 0.2-0.6 inches (7.5-16 mm) and a wingspan of 0.9-1.4 inches (25-35 mm). The males are less than half as big. They are only 0.09-0.25 inches (2.5-6.5 mm) long.


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Body

The female black widow has a ball-shaped abdomen, while the males have a more elongated body. Both have long legs, although the males' legs are significantly longer compared to their bodies.

Color

All species of black widows have two things in common: The females are black and have red markings on their bodies, mostly in the shape of an hourglass. However, in some species it can also be missing. The males are more dark brown.

Black Widow Size Black Widow Size - Photo: Shenrich91 [CC BY-SA 3.0], via Wikimedia Commons, nathanipha99 (pea)/stock.adobe.com

Diet

Black widows are carnivores. They feed primarily on arthropods, beetles, crickets, cicadas, grasshoppers and other spiders. The southern and western black widows even manage to kill small mice.

Black Widow With Prey Black Widow With Prey - Photo: Therina Groenewald/stock.adobe.com

Behavior

Net-Building

Black widows use their silk to weave webs that look very irregular and chaotic. In fact, every single thread is planned and not a coincidence. There are sticky catching threads, supporting threads and tangled threads. The nets are almost always located near the ground, preferably in dark places. The diameter is 15-60 cm.

Hunting Strategy

Black widows are stalkers. They spin a web and hang upside down waiting for prey to get caught in the sticky threads. The spider then quickly approaches, paralyzes its prey with its venom and wraps it in silk.

Black Widow Male Black Widow Male - Photo: Kork~commonswiki [Public Domain], via Wikimedia Commons

Are Black Widows Aggressive?

Black widows look aggressive, but are rather peaceful and shy. When threatened, they flee to a dark corner. However, when they feel trapped and see no escape, they bite.

Are Black Widows Dangerous?

For People

Black widows target small insects and arthropods, but they can also be dangerous to us humans. Especially the females. They have the most venom. Fortunately, human deaths are very rare and are usually related to an allergy to the venom. However, you should seek medical attention immediately if you suspect you have been bitten by a black widow.

For Pets

Pets like dogs and cats can face serious risks from bites since they're much smaller and lighter than us. In humans, the venom spreads over a larger body mass, making it less dangerous.

How Do You Get Rid of Black Widows?

Black widows dislike the smell of lime, eucalyptus, peppermint and tea tree oil. Anyone who sprays these scents or works with cleaning products that contain these scents can keep the spiders away naturally.

Venom

The black widow has a powerful venom called latrotoxin. It can cause severe pain, muscle cramps, vomiting, high blood pressure and sweating. Discomfort occurs 20 minutes to two hours after the bite and can last up to a week.

Black Widow Female Black Widow Female - Photo: Sphoo [CC BY-SA 3.0], via Wikimedia Commons

Senses and Abilities

Senses

Black widows have a very poor sense of vision, but they have an excellent sense of touch. They perceive prey and enemies primarily through vibrations on their web or on the ground. They also have a good sense of smell.

Life Expectancy

Female European black widows live up to 300 days. The males live about 180 days. Female southern black widows can live up to three years.

Enemies and Threats

The natural enemies of the black widow are primarily wasps, birds, small rodents and reptiles.

Importance for the Ecosystem

Black widows play a crucial role in nature's balance. They might have a bad reputation for being venomous, but they're actually beneficial. They help control the population of pests that can harm vegetables, fruits, and ornamental plants.

Redback Spider (Black Widow) Redback Spider (Black Widow) - Photo: RealityImages/stock.adobe.com

Reproduction

After mating, black widows lay up to 100-250 eggs in a white to yellowish egg cocoon. The young animals hatch after around 30-50 days. Once they leave the cocoon, they are on their own. It is said that the black widow eats the male after mating, but in reality this happens very rarely.

Fun Facts

Color

There are also brown widows and white widows.

Confusion with the False Black Widow

The European black widow is often confused with other spiders that look similar to it. For example with the false black widow - whose venom is much weaker.

False Black Widow False Black Widow - Photo: Bernard DUPONT from FRANCE [CC BY-SA 2.0], via Wikimedia Commons


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