Do you remember the cute, but unwanted, spider I showed two days ago?

I'm talking about this one:

Do you also remember that the snail it met called her a "widow" right before it "jumped out of the window"?

Well, I got news for you...

Hey, snail, you too!

This round-belly spider is not a Black Widow, even though it looks a lot like one.

This spider belongs to the Steatoda genus of the Theridiidae family (AKA tangle-web or cobweb spiders). Steatoda can be found all over the world and they like darkness and quiet (not the most cheerful environments, I guess). They make complex tangle webs with their sticky, silken threads that are weaved in a criss-cross pattern and get denser towards the center of the structure. Some species of the Steatoda spiders are very much like black widows, but they are not as harmful to humans as them, therefore they're also called false black widows. Out of the almost 120 recognized species of Streatodae, S. borealis, S. capensis, S. grossa (or Cupboard Spider), S. nobilis (or Noble False Widow Spider), S. bipunctata (or Rabbit Hutch Spider), and S. Paykulliana are mostly mistaken for black widows. [1, 2]

Here, have an original widow to see the difference

Image from: commons.wikimedia.org - Courtesy of: Chuck Evans(mcevan) - License: 2.5 Generic (CC BY 2.5)

The real deal belongs to the Latrodectus genus of the same with the Steatoda family. They are usually dark brown or black and have the typical red or orange hourglass mark on their underside abdomen or maybe two red spots if nothing at all. Males differ a little from females, as they might bear red or red and white marks on their upside abdomen.

These spiders are infamous for their not so gentle love life, as females seem to practice sexual cannibalism (just like mantises). As we mentioned in a past post, for mantises to devour the male while ejaculating, increases the success odds of mating; black widows also eat their partner possibly to guarantee their offspring will get their valuable nutrients. What's even weirder here is that just like with mantises, cannibalism incidents in black widows were more commonly observed in spiders held in captivity. [1, 4, 5]

Back to the fake ones

Sumo wrestlers with multiple arms

Their anatomy is kind of funny, they have a smaller head and thorax compared to their larger and oval-shaped abdomens (which in my disturbed mind makes them look like sumo wrestlers). Also, males seem to be relatively smaller than females. [1, 2]

What do they eat?

Streatoda feed on insects like crickets, cockroaches and woodlice. They eat other spiders too. And some Streatoda species may even feed on widows (a bit ironic, isn't it?). [1]

They love humans

These spiders are synanthropic species, which means that they live around them (if not with them). [2]

They don't eat their men, but they outlive them

Females live longer than males. With a life expectancy of a few years, female Streatoda may go without water for a long time. Males, on the other hand, survive only a few months and show up mostly in summer or autumn and when they reach maturity they stop eating. Their sole cause is to reproduce and then... bye, bye! [2]

They can't see well

Streatoda are not blessed with acute eyesight, therefore they rely on vibrations perceive their surroundings. Movements on their webs inform them where to head in order to get their meals. Males also use sound signals to attract females by producing vibrations with their abdomens (crazy real-life scenario: a man banging his plump belly and a woman running wildly turned on towards him... and for some even crazier reason Austin Powers came to mind). [1, 2]

Remember that spiders can travel... everywhere?

So can these ones! Through ballooning (a technique where spiders make DIY balloons with their silken threads and wait for the wind to carry them away - we talked about it in a Bizarre Phenomenon post) Streatoda can travel short distances (cheap and eco-friendly). But it is not uncommon for spiders become stow aways in shipments and make it into countries where they were never seen before. [2]

Do they bite?

If they are disturbed or threatened, they won't hesitate to use their fangs! Their venom is not as toxic as a widow's, but it can still give you steatodism (the term used to refer to the symptoms of the bite). The bite will be similar like one from a widow (latrodectism), but symptoms will be milder. Pain is stronger than that from a bee sting and may take 1-12 hours to go away (in rarer cases it may take longer than a day) expanding from the limbs to the rest of the body. Malaise, nausea, headaches and lethargy are among the symptoms and allergic reactions to their venom are rare. So, seeking for medical care is not always necessary. Simply treating the bite with soap and water and then by placing some ice over it will do. Some painkillers will also help to ease the pain, which if persists, it's a sign that you should see a doctor. [1, 2, 3]