Episode 212 – Black Widow Spider: Bad Reputation

“…And today we’re talking about a woman who doesn’t give a darn about her bad reputation.”

The black widow spider is nature’s ultimate example of the femme fatale. An unyielding queen in the middle of her silken throne, waiting for the lowly male, driven to her by an instinct most basic.  Though her signature red hourglass may be a reminder that our days are numbered, the widow’s reputation may not paint the full picture. Still, she’s just one of many animals that engage in a sinister practice that’s common in Life, Death, and Taxonomy. 

Description of the Black Widow Spider

  • Females are large, girthy orb spiders with long legs and bulbous abdomens.
  • Their bodies are jet black with a trademark red hourglass mark on the undersides of their abdomens
  • The males are much smaller and have brown bodies with cream-colored markings on their abdomens
  • Males also have large palpal organs on their mandible-like appendages called pedipalps

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We do have a new Measure Up intro! 


  • 14–16 mm (1/2 in)
  • How many black widows go into the length of the world’s largest commercially available pizza?
  • Hint: The pizza, known as “The Bus,” is offered by Moontower Pizza Bar in Burlson, Texas. It costs nearly $300 to buy. You can even have it delivered, but you need to give the restaurant 48 hours notice.
  • 192 black widow spiders. The pizza is 8 ft x 2 ft 8in.


  • 0.9 grams (0.035 ounces)
  • How many black widows would go into the greatest combined weight of boxers in a fight?
  • Hint: In 1971, Claude `Humphrey’ McBride from Oklahoma and Jimmy Black from Houston. 
  • 352,290 spiders. McBride was 154 kg. (339 lbs) and Black was 163 kg (359 lbs), which is 699 lbs in total.

Fast Facts about the Black Widow Spider

  • Range: Western North America
  • Diet: beetles, ants, wasps, and bees mostly. They’ll also eat each other when they’re starving, there isn’t any other food around, or they’re fighting and things get out of hand. 
    • They’ll even eat their own siblings. But this species of black widow actually doesn’t make a consistent habit out of intentionally killing and eating the males after mating. Males can mate several times – though they don’t have a very long life span (100 days). 
    • However, females are picky with their mates, and rejection often leads to being eaten before mating even happens.
      • Other nearby males give off a chemical cue telling the female that there are other fish in the sea. If she decides that she can do better than the male that’s advancing, she’ll attack him.
      • Also, mating is pretty rough for the male, so his reproductive organs could get injured or destroyed in the snoo snoo process. If that happens, he won’t be able to mate again and will probably just die in her web. The female will then likely just eat him since it’s free food.
    • Females can also detect chemical cues from their prey – so they’ll use those to decide where to set up shop.
      • In fact, exterminating the prey of the black widow is a great way to make sure they don’t decide to set up shop in your house. 
  • Behavior: 
    • They weave disorganized webs out of silk that has a tensile strength higher than steel. Females can shoot a glob of silk at predators.
    • They are mostly blind so the strands are covered in a pheromone that allows them to identify each other. As soon as a male comes into contact with a female’s web, he’ll start his courting behavior – which involves giving off his own pheromone.
      • As soon as the female smells the male’s pheromone, she’ll hold off on killing him until she mulls it over.
    • Black widows are known for being pretty dangerous spiders
      • Their venom is a powerful neurotoxin that paralyzes prey.
      • It’s pretty uncomfortable for humans to be bitten by one, but it hasn’t really shown to be fatal. 
      • In humans, it causes irritation, pain, nausea, muscle spasms, and excessive sweating.

Major Fact: Bad Reputation

Black widows are probably the most famous example of sexual canabalism, which is when an animal eats its mate after mating. In fact this practice is how they got their ominous name.

But as we’ve heard several times before, eating your mate is not all that uncommon in nature, especially in the world of small arthropods. 

The black widow female’s reputation as a femme fatale may be an overblown rumor at best and libelous at worst. 

The courtship routine of black widow’s is complex and the males may sometimes be more like a court jester than a suitable suitor. The courtship behind when a male happens upon the female’s web, after catching the scent that covers her silk. 

He will tap on the web to show his interest and vibrate his abdomen to increase the vibrations on the web. If the female is uninterested, she’ll drive the male away, leaving him to date and die another day.

To increase his odds, the male will kill two birds with one stone. He will cut the lines of the female’s web, making it smaller. This will cut off some of the female’s escape paths, but it also cuts down on the surface area of the web, which lowers the chance of another male catching her scent. 

There’s a chance that the female will proactively eat a male if she smells a lot of other male pheromones in the area. But before mating initiates, the male will construct a bridal vail, which is drapery of his own silk that he surrounds her with, creating an aura of his pheromone all around her.

If she is receptive, she’ll mimic the male’s vibration and copulation will commence. When the dead is done, the act leaves the males reproductive parts damaged and inert. 

Here’s where the rumors start. Becaused the male has damaged organs, sometimes, he straight up dies. Then, not one to waste resources, the female will eat him. In some cases, knowing his job is done, the male will literally move to her mouth parts to be eaten. In many examples of sexual canabalism, it’s a planned strategy to give the mother and babies all the resources they need for success. 

Still, there are only two black widow species that almost always involve sexual canabalism. Most of the more than 30 species rarely engage in sexual canabalism. 

Ending: So weave strong silk, keep your webs disorganized, and always give off the right pheromones like the black widow here in LDT.