Black Widow Spider Male vs Female: Unraveling the Differences

folder_openArachnida, Araneae
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Black widow spiders are fascinating creatures known for their distinct appearance and venomous bite. They belong to the genus Latrodectus and can be found in various parts of the world.

One interesting aspect of black widow spiders is the significant difference between males and females, which plays a vital role in their society, size, and behavior.

The female black widow spiders are larger and more dominant than their male counterparts. In fact, their size can be up to double that of the males.

Black Widow Spider Male vs Female
Immature Black Widow

Females are also known for their trademark black body with a red hourglass-shaped marking on their abdomens. Males, on the other hand, are more of a brownish color and lack the distinct red marking.

Mating behaviors among black widow spiders are particularly unique. Female black widows are generally aggressive and may even consume the males after mating.

This act is believed to provide essential nutrients for the female and her future offspring.

In contrast, male black widows try to minimize their risk during mating by selecting less aggressive females, performing intricate courtship rituals, and even producing a chemical signal to reduce the female’s aggression.

As evident, the differences between male and female black widow spiders are vast, transcending from their physical appearance to their behaviors.

These characteristics contribute to their successful survival strategies and have made them a subject of fascination for many.

Black Widow Spider Male vs Female: Identification

Hourglass and Red Spots

Black widow spiders, both male and female, are known for their distinct markings. Female southern black widows have a shiny, jet-black body with an orange to red hourglass marking on their abdomen’s underside.

The males, however, display spots and stripes of red, orange, and/or yellow on the upper surface of their abdomens.

Here’s a comparison of the markings:

Feature Male Black Widow Female Black Widow
Hourglass No Yes, underside
Red Spots Yes, on top of abdomen Variable, on top of abdomen

Body Size and Coloration

The body size also differs between males and females. Female black widows’ bodies are typically 8-13mm in length, measuring 25-35mm with extended legs. Male black widow spiders are much smaller with a white underbody.

A summary of body size and color for both genders:

  • Male Black Widow:
    • Smaller body
    • Black body, white underbody
    • Red, orange and/or yellow markings on abdomen
  • Female Black Widow:
    • Larger body
    • Shiny black body
    • Red hourglass on abdomen underside
    • Variable red spots on top of abdomen

It’s important to differentiate between male and female black widow spiders, as females pose a more significant threat to humans due to their venomous bite.

Immature, female Northern Black Widow

Behavior and Habitat

Web Construction and Communication

Black widow spiders create irregular, messy webs with strong silk.

These webs serve as a way to capture prey and communicate through vibrations. Here are some key features of black widow webs:

  • Made of very strong and sticky silk
  • Usually found in dark, secluded areas like woodpiles and garages

Comparing male and female black widow spiders, males tend to build smaller webs and wander more frequently in search of females for mating.

Prey and Diet

Black widow spiders primarily feed on insects such as flies, mosquitoes, and grasshoppers. The diet of both female and male black widows generally includes:

  • Insects
  • Small arachnids
  • Occasional small vertebrates

Female black widow spiders are known to be more aggressive than males when it comes to hunting and capturing prey.

Mating and Reproduction

Mating and reproduction in black widow spiders involve unique and complex behavior. Male black widows identify potential mates through pheromones on the female’s silk.

They then perform a courtship dance to avoid being mistaken as prey. The following points summarize mating and reproduction in black widow spiders:

  • Female black widows are known for sexual cannibalism, sometimes consuming the male after mating.
  • Females can store sperm for several months, producing multiple egg sacs from a single mating.
  • Lifespan: Males typically live around 6-8 weeks, while females can live up to 3 years.
Aspects Male Black Widow Spider Female Black Widow Spider
Lifespan 6-8 weeks Up to 3 years
Aggressiveness Less aggressive More aggressive
Web Size Smaller Larger

Venom and Medical Concerns

Venom Composition and Effects

Black widow spiders, specifically the female ones, are known for their venomous bites.

The venom of the black widow, a neurotoxin called alpha-latrotoxin, is reportedly 15 times more toxic than the venom of a prairie rattlesnake. The effects of black widow bites include:

  • Muscle pain
  • Diaphoresis (sweating)
  • Tachycardia (rapid heart rate)
  • Flushing (redness of the skin)
  • Hypertension (high blood pressure)
Black Widow

Treatment and Antivenom

In case of a black widow bite, it is essential to seek medical treatment immediately. Treatment generally consists of:

  • Opioid analgesics for pain relief
  • Muscle relaxants to ease muscle cramps
  • Antivenom for severe cases

Contacting local poison control centers can provide additional guidance on managing the symptoms of a black widow bite.

Black Widow

Prevention and Safety Measures

To minimize the risk of black widow encounters, follow these safety measures:

  • Avoid disturbing areas where black widows commonly reproduce, such as late spring or early summer
  • Be cautious when handling firewood, debris, or items in storage areas
  • Wear gloves and protective clothing while working outdoors or in areas where spiders may inhabit
  • Regularly inspect and seal any cracks or openings in building structures

It is important to correctly identify black widow spiders. Some key identifying features include:

  • Female southern black widow spiders are shiny and jet black with an orange to red hourglass marking on their undersides
  • Males are smaller, black, and have white markings under their bodies
  • Black widows typically range from 8 to 13 millimeters in body length, extending to 25 to 35 millimeters with their legs

Though black widow spiders are venomous, by taking proper precautions and being vigilant, the risks associated with these spiders can be reduced significantly.

Comparison of Male and Female Black Widow Spiders

Physical Differences

  • Male black widow spiders:
    • Smaller in size, around 1/4 of females
    • Brown or gray color
    • Red and white stripes on abdomen
  • Female black widow spiders:
    • Larger in size, up to 1.5 inches body length
    • Black with a signature red hourglass marking on abdomen

Both male and female black widow spiders belong to the spider species Latrodectus, which are part of the arachnid family.

Behavioral Differences

  • Male black widow spiders:
    • More mobile and active
    • Tend to wander in search of females
    • Less venomous and not a threat to humans
  • Female black widow spiders:
    • More solitary and sedentary
    • Build webs in dark corners, crevices, basements, closets, and cluttered areas
    • Prey on flies, grasshoppers, beetles, and other insects
    • More venomous and considered dangerous to humans

Black widow spiders can be found in various locations, including Florida and Texas.

Immature Black Widow

Reproduction and Cannibalism

During copulation, the male black widow spider approaches the female while she is upside down on her web.

After mating, the female may exhibit cannibalistic behavior by consuming the male. However, this behavior is not always observed in the wild.

  Male Black Widow Spider Female Black Widow Spider
Physical    
Size Smaller Larger
Color Brown or gray Black
Markings Red and white stripes Red hourglass
     
Behavioral    
Mobility More active More sedentary
Threat to humans Less venomous Highly venomous
Habitat preference Wandering Solitary in dark corners
     
Reproduction Seek mates Can cannibalize mates

In summary, male and female black widow spiders exhibit significant differences in physical appearance, behavior, and reproductive habits.

Conclusion

Black widow spiders are captivating creatures with distinct appearances and behaviors.

The stark differences between males and females, from size to coloration, play a pivotal role in their mating rituals and survival strategies.

While the venomous bite of the female black widow demands caution, understanding their habits and habitats can significantly reduce encounters.

By recognizing their unique characteristics and taking preventive measures, we can coexist with these remarkable arachnids while ensuring our safety.

 

 

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Black Widow Spider

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8 Comments. Leave new

  • ARE YOU CRAZY!?!? I WOULDN”T EVEN GET CLOSE TO ANY SPIDERS! LET ALONE TOUCH ONE!

    Reply
  • What a beauty!

    Reply
  • The speckled brown/white/black sacs on bottom of lawn chair below the pic of black widow male is from the bolas spider. It’s an amazing spider. Here is a video of how it catches prey. http://m.youtube.com/watch?v=nrm2rnDOZQI

    The one I found was under my palm frawn and looked like bird poo. When it walked it had crab-like legs.

    Reply
  • The speckled brown/white/black sacs on bottom of lawn chair below the pic of black widow male is from the bolas spider. It’s an amazing spider. Here is a video of how it catches prey. http://m.youtube.com/watch?v=nrm2rnDOZQI

    The one I found was under my palm frawn and looked like bird poo. When it walked it had crab-like legs.

    Reply
  • Black Widow Nope
    August 17, 2015 5:49 pm

    I mostly agree, and I hope they did educate their children, but this will not prevent bites when the kids didn’t see the spider until it was too late.

    “Black Widows are not an aggressive species, and they are rarely found far from their web, unless they have been disturbed. We once allowed a Western Black Widow to keep her web by our porch light. We knew she was there and we were not concerned about getting attacked.” Yes, but the spiders are on/under the thing the kids are playing with (i.e. the hoop). While going to make a basket, they could accidentally come into contact with a frightened large black widow spider protecting her eggs. It’s the classic situation when this spider which normally avoids humans might bite. A porch light is quite different. They shouldn’t have to stop playing basketball just because a few spiders decided to make it their home uninvited. And how do you educate your *dog* or cat to avoid them?

    We should never kill or harm a living thing for no reason, and if something is not dangerous to us we should leave them alone, but these people did not go on a mindless slaughter by any means. They discovered they had spiders with a bite that can cause severe symptoms and can be life-threatening for children and small animals and chose the option that resulted in the fewest total deaths while decreasing their immediate risk. I’m a vegan, I believe all life is valuable and we should respect nature but I understand that sometimes we have to make sad/tragic choices to protect our loved ones and it doesn’t mean we’ve done something wrong.

    Reply
  • Black Widow Nope
    August 17, 2015 5:49 pm

    I mostly agree, and I hope they did educate their children, but this will not prevent bites when the kids didn’t see the spider until it was too late.

    “Black Widows are not an aggressive species, and they are rarely found far from their web, unless they have been disturbed. We once allowed a Western Black Widow to keep her web by our porch light. We knew she was there and we were not concerned about getting attacked.” Yes, but the spiders are on/under the thing the kids are playing with (i.e. the hoop). While going to make a basket, they could accidentally come into contact with a frightened large black widow spider protecting her eggs. It’s the classic situation when this spider which normally avoids humans might bite. A porch light is quite different. They shouldn’t have to stop playing basketball just because a few spiders decided to make it their home uninvited. And how do you educate your *dog* or cat to avoid them?

    We should never kill or harm a living thing for no reason, and if something is not dangerous to us we should leave them alone, but these people did not go on a mindless slaughter by any means. They discovered they had spiders with a bite that can cause severe symptoms and can be life-threatening for children and small animals and chose the option that resulted in the fewest total deaths while decreasing their immediate risk. I’m a vegan, I believe all life is valuable and we should respect nature but I understand that sometimes we have to make sad/tragic choices to protect our loved ones and it doesn’t mean we’ve done something wrong.

    Reply
  • My ex was bitten by a brown widow after moving a ladder the widow had nested in, with egg sacs. She was apparently very protective of the sacs (they are actually described this way by entomologists), and bit my ex twice on his calf. His arms seized up repeatedly and he felt really ill on the first day. He was sick for about two weeks, in all, mostly feverish, with heart palpitations. He did not go to the doctor, despite my advice.

    He said he felt “mini-heart attacks” for about a year afterwards.

    Not realizing the nesting problem, he stashed the ladder on our front porch. I ended up extermniating at least couple of hundred brown widows from the front yard area over the next few years – 60 the first night, 40 the second night, and so on. It took about 7 years of this to finally extinguish the breeding.

    Reply

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