Stunning, sly, and ruthless, with legs that go all the way to her abdomen,
this bulbous beauty could knock you out with just one bite.
But don't jump to conclusions.
This iconic arachnid is mostly misunderstood.
She's not a bad girl, she just looks like one.
This is the Black Widow.
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Black widows are a type of spider perhaps best known for... well you know, sexual cannibalism.
That memorable behaviour is where the Black Widow got its name.
But you might be surprised to learn that the rumours of their treachery
are greatly exaggerated.
There are over 30 species of Black Widow,
ScarJo notwithstanding, but only a few of those choose to make their lovers a post-coital snack.
So let's not stereotype these venomous vixens.
Some Black Widow sport the iconic all black body,
and the red hour-glass shaped markings on their abdomen.
But most species actually come in a wide variety of colours,
from brown, to red, to completely black.
Their life expectancy also depends on their species.
Females generally live a lot longer, and are much, much, larger than the males.
Black Widows have been around for about a hundred million years and can be found all over the world.
They like warm, dry climates, and prefer to spin their webs in dark,
sheltered spots close to the ground.
They feed on flies, mosquitos, beetles, caterpillars, worms, grasshoppers, and hydra.
You know, typical spider food.
When the Black Widow catches their prey,
they wrap more silk around them, and paralyze them with venom.
Their venom is 15 times more toxic than a rattlesnakes.
Not exactly a peaceful death.
Black Widows use their sense of smell for a lot of the same things we do:
avoiding predators, tracking down food, and finding shelter.
But chemoreception is far more important for them.
It's actually their main means of communication.
The chemicals used to communicate are called pheromones.
Most people associate the word with scents that make you attractive.
But in the animal kingdom, they play a much larger role.
Pheromones have been used since some of the very first animals,
and possibly by other lifeforms before them.
When it's time to mate, the female Black Widow releases pheromone-laced silk onto her web.
Those pheromones evaporate into the air and float far and wide,
acting as a siren song to attract potential mates.
"Come to my web, you cannot resist me!"
Thank you, that is my impression of Lolth, Queen of spiders.
The pheromone signal becomes strong thanks to a process called sender-receiver co-evolution.
The females who send the most attractive chemicals,
are the most likely to pass their genes onto the next generation.
Enter the male widow.
Like the females, this little guy has inherited quite the impressive genes from his fore-spiders:
the ability to detect female pheromones in an ocean of chemicals.
It's thanks to evolution that these two have mastered the science of sexual communication.
It's time for this male to show off just how good he is at picking up on sexy signals.
If he's actively searching for a mate, he'll crawl up to a high place
and wave his arms around a bunch.
And then, he'll smell them to see if he's caught any pheromones.
Very subtle stuff.
When he gets a hit, this spider heads straight to his potential partner, like a moth to a flame.
Or, you know, like a male spider to a Black Widow's web.
Some of you may be thinking, "Oh no, this poor little spider-man
he has no clue he's about to become brunch."
But, remember, only a few species are sexual cannibals.
And for those femme fatales famous for feeding on males?
Well it's only if they're in the mood for a snack.
If the male is smart, he'll mate with her after she's eaten.
How does he know if she's full?
Chemoreception!
If his sense of smell tells him that she's starving,
he instinctively knows not to get any closer.
The female's web is covered in pheromonal discharge.
Now we get to see how those pheromones work via direct contact.
When the male touches the web,
he's sort of tasting the female's pheromones, and gets kicked into romance mode.
The chemicals trigger his courting behaviour.
This doesn't mean wine, roses, and back rubs. Nope!
Black Widows opt for vibrations.
The female Black Widow doesn't even care that her mate seems weak and tiny.
She's more concerned about his moves.
And although her pheromones may have communicated she was looking for a mate,
she may not be entirely sold on this male.
Get off!
Then his plan hits a snag.
Another, bigger male, who's also been attracted by the female's pheromones, wants to shoot his shot.
And he's not wasting any time!
He immediately mounts the female Black Widow!
And it's on!
The two spiders battle it out for the female's attention.
Who will win?
Even though the smaller male put in all the hard work to court the female,
the new guy has the edge because of his size.
Please take it somewhere else boys!
As usual, the bigger male wins out.
Now to enjoy his success.
He tries his luck at inserting his two palps, the sexual organs around his fangs
that look like black balls, into the female's epigynum... the genital opening on her abdomen.
Success!
As soon as the palp goes inside the female,
it curls up like a spring and then he gives her his sperm.
Aw, how sweet!
Mating can last up to 20 minutes.
Right about now, those hypnotic pheromones start to wear off.
Will the male end up in the mouth of his mate?
Or is this his lucky day?
He walks away unscathed.
He managed to survive a tango with the iconic Black Widow.
What a badge of honour!
Once the male leaves, the female can now lay her eggs in a gorgeous silky egg sack.
These sacks can hold up to 300 eggs,
and the sperm her male partner gave her can produce up to 10 viable egg sacs.
Which means, this one tryst could result in 3,000 new baby spiders.
Bye bye bikinis.
All in all, a highly productive day for Black Widows.
Well done, you two!
A credit to your species!
So what should we talk about next?
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Thanks for watching, see you later.