Sticky feet help tarantulas climb

 

The study raises interesting questions about spider evolution

 

Tarantulas can climb walls because they ooze a sticky silk through their feet. Scientists have shown how spiders made to scale vertical glass surfaces will secrete a fibrous "glue" to anchor themselves down and prevent a fall.

Arachnids are known to use claws to negotiate difficult terrain, and they also have tiny hairs that can form weak electric attractions with a surface.

But the silk represents a previously unrecognised climbing technique, a German team tells the journal Nature.

"We have discovered that the tarantula has a third attachment mechanism, which depends on fibres exuded from nozzle-like structures on its feet," Stanislav Gorb, from the Max Planck Institute for Developmental Biology in Tubingen, and colleagues write.

"These fibrous secretions function as silken tethers and, when laid down on glass plates, appear as 'footprints' that consist of dozens of fibres with diameters of 0.2-1.0 [millionths of a metre]."

The team studied how zebra tarantulas (Aphonopelma seemanni) from Costa Rica managed to hang on to vertical glass plates.

To walk up, the spiders employed their distal claws; but to come down they oozed a silky substance from all four pairs of feet.

Controlled adhesion

The team believes the mechanism raises interesting questions about arachnid evolution.

Generally, spiders will extrude a silk from abdominal structures known as spinnerets. This fine thread is used in a range of activities from capturing prey to providing protective shields for developing young.

The team wonders which of the adaptations - foot silk or abdominal silk - came first; or, indeed, if they evolved completely independently.

Commenting on the research, spider expert Professor Fritz Vollrath from Oxford University, UK, said foot silk had been regarded as something of an "old wife's tale" that no scientific team had sought to describe in detail.

"It's incredible - just like Spiderman. If the stuff is so good he can pull a train around, how does he get it off?

"And that's the thing for the spiders: first they have to glue themselves down and then they have to get themselves off again. It's very clever," he told BBC News.

Some answers to the evolution questions might come from a thorough genetic analysis of foot silk, the Max-Planck-led team said.

You bas*/*!!

 

Was there any need for the picture????

 

SOME OF US HAVE PHOBIAS!!

 

*shakes fist*

You bas*/*!!

 

Was there any need for the picture????

 

SOME OF US HAVE PHOBIAS!!

 

*shakes fist*

 

Have you not heard of hypnotism?? Works a treat!!;)

Neil, at least you're man enough to admit it.

Yeah i have the same problem...:shocked2:

Yeah i have the same problem...:shocked2:

 

Well that must be a big problem living where you do, because there are some pretty huge spiders!!:stunned:

Is there a "sheep-eating" spider??:rolleyes:

Yeah i have the same problem...:shocked2:

 

Me too ever since i was bitten by a black widow spider.

Me too ever since i was bitten by a black widow spider.

 

:stunned:

 

What kind of effect did it have on you? Did you have to go to hospital?

Yeah, I dont remember much i was 4, but apparently the spider used most of its venom on something else so i was ok. It was my second ride in a ambulance. First being after my parents thought i drank some of my dads eye drops

Yeah' date=' I dont remember much i was 4, but apparently the spider used most of its venom on something else so i was ok. It was my second ride in a ambulance. First being after my parents thought i drank some of my dads eye drops[/quote']

 

I heard it's most dangerous if you're very young, and that black widow bites are very rarely fatal.;)

Ever since it bit me my goal in life has been to find it and kill it...

Looked under the bed??

Hahaha yeah.

Hahaha yeah.

 

And what did you find??

A dead hooker.

A dead hooker.

 

Can't say I'm surprised!!:P

I was the last hooker i had was 4 years ago....:o

 

No wonder why she smelled.

I was the last hooker i had was 4 years ago....:o

 

No wonder why she smelled.

 

You were a hooker??:stunned::shocked2::stunned:

You were a hooker??:stunned::shocked2::stunned:

 

Oops typo. I meant the last hooker I had was 4 years ago.