Thursday, May 6, 2010

Arachnologist needed!

I recently returned to the Mara after being back in the states and quickly settled into my new tent. However, in the first couple of days I had to evict some of the small guests that had been calling my tent their home. This one in particular caused me to lose a little sleep. I have a guess at what type of spider this may be, but I welcome the opinion of someone the knows a bit more about spiders.


Anonymous said...

Latrodectus hasselti? The bigger question is: male or female? The Australian Museum offers some insights:

metroidgearsolid said...

That looks like a red hourglass shaped marking. if it is then it is a female black widow and it is deadly.

Anne Engh said...

Hey Andy-
I had that same type of spider living at my tent back in my Mara days. One bit of advice: If you find an egg sack in its web, don't do the standard biologist poke-it-with-a-stick test. When I did that, zillions of teeny tiny (and amazingly fast) spiders came out of the sack and ran straight into my tent (through the mesh). Lions walking around outside my tent never bothered me much, but having tons of tiny potential black widows IN my tent did.
I gathered the remaining egg sacks and burned them gleefully.

Mollie said...

You should email Dr. Snider.

Muhindimzungu said...

Sorry to come so late to the conversation (I'm only 2 years late):
Its a Latrodectus geometricus (Brown Button) female.

It's venom is not nearly as dangerous as a Black Button (Latrodectus indistinctus), which, happily, does not occur in Kenya.
If you get bitten, which is very unlikely due to its placid nature, you might not feel well for a few days, but its far from deadly.

Brown Buttons are very common in the Mara, especially in tents! They love dark corners, like the area behind your toilet cistern, under a washstand/sink, that sort of thing. They're web-bound, so they're not going to be walking around, prowling over your face as you sleep. They WILL NOT leave their web unless its been destroyed.
If you have the chance, throw a small ant in its web at night time when it's active and watch it feed. Its fascinating stuff!
Also keep an eye out for a little funnel retreat off to one side of the web. If its not inaccessible, have a look in there and you might see some of the egg casings. They look like little round balls covered in spikes. Often, if that particular individual has been there for a while, you will find more than one old empty egg casing.

The males are much smaller and their markings less distinct.

In the West, Latrodectus are called Widows because of the female's tendency to kill the male as soon as she's done mating. He'll do a little dance and rub her legs and convince her that he's not food in order to get close enough to mate (her eyesight is pretty crap). But as soon as he's done, she forgets all that and instinct kicks in! If he's quick, he'll live to see another day, but often she's faster (and much bigger) and he'll be lunch!

Wowzers. Didn't set out with the idea to write an essay. Pole.

Michigan State University | College of Natural Science