How does tarantula climb?

Y

Yawen

Arachnopeon
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I have read an article,

Tarantulas cling to smooth vertical surfaces by secreting silk from their feet,

http://jeb.biologists.org/content/214/11/1874.abstract?sid=3db4cfbb-9af0-4c90-bc80-204e7f6e7fef

but i also read this in WIKI,

Two or three retractable claws are at the end of each leg. These claws are used to grip surfaces for climbing. Also on the end of each leg, surrounding the claws, is a group of hairs. These hairs, called the scopula, help the tarantula to grip better when climbing surfaces like glass.

I am confused now. What is the climbing mechanism of tarantula? Using silk or scopula?
 
Jared781

Jared781

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when i Handle my Ts, it feels like they have little hooks :p

then i thought about the movie Spiderman, and when peter parker looked at his hands

hooks started to grow :/ ahaha
 
Ciphor

Ciphor

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The spider silk story is a theory, and is not yet proven. I've been following it though, as it is pretty interesting stuff.

The anatomical feature that allows spiders to "climb" and tarantulas to walk right up smooth glass, is called the scopulae. This is located behind the tarsus claws, and is best described as a "blunt tuft" that helps the spider with traction.

I found a picture of Poecilotheria fasciata scopulae incase my description didn't paint a very good picture. http://thebts.co.uk/forums/gallery/...&title=p-fasciata-iridescent-scopulae&cat=500

The tiny hairs are called setule, and working together they generate a strong adhesion to smooth surfaces.
 
Last edited:
Y

Yawen

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Ciphor said:
The spider silk story is a theory, and is not yet proven. I've been following it though, as it is pretty interesting stuff.

The anatomical feature that allows spiders to "climb" and tarantulas to walk right up smooth glass, is called the scopulae. This is located behind the tarsus claws, and is best described as a "blunt tuft" that helps the spider with traction.

I found a picture of Poecilotheria fasciata scopulae incase my description didn't paint a very good picture. http://thebts.co.uk/forums/gallery/...&title=p-fasciata-iridescent-scopulae&cat=500

The tiny hairs are called setule, and working together they generate a strong adhesion to smooth surfaces.
Click to expand...
Thanks a lot... The story of spider silk really confuses me.
 
A

Anonymity82

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Ciphor said:
The spider silk story is a theory, and is not yet proven. I've been following it though, as it is pretty interesting stuff.

The anatomical feature that allows spiders to "climb" and tarantulas to walk right up smooth glass, is called the scopulae. This is located behind the tarsus claws, and is best described as a "blunt tuft" that helps the spider with traction.

I found a picture of Poecilotheria fasciata scopulae incase my description didn't paint a very good picture. http://thebts.co.uk/forums/gallery/...&title=p-fasciata-iridescent-scopulae&cat=500

The tiny hairs are called setule, and working together they generate a strong adhesion to smooth surfaces.
Click to expand...
Sweet info. Thanks! Really good to know!
 
jbm150

jbm150

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Have you ever messed with their feet, like from an exuvium? If you rest the scopula against your finger and pull down, similar to how a T might hang upright, it slides fairly easily (though the claws will hook). But if you push forward, simulating a T hanging upside down, it sticks incredibly well.

So, from what I would imagine, when they're upright on a vertical smooth surface, their back legs support their weight and the front legs that aren't reaching for a new foothold, might actually be pushing slightly forward. They kinda push their feet away from the center of their body to create grip. Play with an exuvium sometime, see what I mean and if that makes sense....
 
xhexdx

xhexdx

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It wasn't hooks growing out of Peter Parker's hands - it was thousands of tiny hairs.

Tarantulas use these hairs, called scopulae, to cling to smooth surfaces. Their tarsal claws are used in addition to scopulae to climb rough surfaces.
 
T

twentyeggs

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no no no no..... really? so many people don't know the answer to this simple question.... all the answers are WRONG!! tarantulas all have tiny little anti-gravity devices... they switch it on and climb away!!
 
Jared781

Jared781

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xhexdx said:
It wasn't hooks growing out of Peter Parker's hands - it was thousands of tiny hairs.

Tarantulas use these hairs, called scopulae, to cling to smooth surfaces. Their tarsal claws are used in addition to scopulae to climb rough surfaces.
Click to expand...
very interesting...

thanks!
 
Ciphor

Ciphor

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jbm150 said:
Have you ever messed with their feet, like from an exuvium? If you rest the scopula against your finger and pull down, similar to how a T might hang upright, it slides fairly easily (though the claws will hook). But if you push forward, simulating a T hanging upside down, it sticks incredibly well.

So, from what I would imagine, when they're upright on a vertical smooth surface, their back legs support their weight and the front legs that aren't reaching for a new foothold, might actually be pushing slightly forward. They kinda push their feet away from the center of their body to create grip. Play with an exuvium sometime, see what I mean and if that makes sense....
Click to expand...
I believe the setule are controlled by hydraulic pressure.
 
jbm150

jbm150

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From Ciphor's last source:

Strong friction anisotropy was observed: friction was considerably higher during sliding in the distal direction. Such anisotropy is explained by an anisotropic arrangement of microtrichia on setae: only the setal surface facing in the distal direction of the leg is covered by microtrichia with spatula-like tips. When the leg is pushed, the spatula-shaped tips of microtrichia contact the substrate, wheres when the leg is pulled over a surface, setae bend in the opposite direction and contact the substrate with their spatulae-lacking slides. ....It was shown that dessiccation has an effect on the friction force. Presumably, drying of the legs results in reduction of the flexibility of the setae, microtrichia, spatulae, and underlying cuticle; that dimishes the ability to establish proper contact with the substrate and thus reduces contact forces.
Click to expand...
That works toward explaining two things: my observation that the scopula work best in one direction and Ts nearing molt losing traction on smooth surfaces like glass. Another source I found talks about fluid secretion over the pads; they work both "wet" and "dry" but best when the film is present. I wonder if those secretions may also serve for the type of chemoreception talked about in the thread about web recognition....
 
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