Question for you scholars, About a jump to a safe place.

[Chris Sainsbury]

Hi
Just something I have wonderd about in the passed but just came to me again the other day whilst rehouseing a P. everetti.

How come spiders from Cyriopagopus, Lampropelma and Phormingochilus all curl their legs in kind of bombing action when they jump? Where as with Avicularia, Psalmopoeus, stromatopelma and Heteroscodra (I can't say for other arborel tarantulas) spread their legs out in a kind of parachute or gliding fashion?

Its just something I have noticed from spiderlings and adults of these South East Asian arborel spiders but can't think of any real good reason for it, except maybe to make them fall quicker (less of the parachute effect) and get away that little bit faster? Or do they use their legs protect their bodies from impact in some way?

The only other thing I could come up with that may have something to do with it is the different type of forest in South East Asia when compared to that in maybe the Americas and Africa. I sugest this because of a documentry I once saw that explained that the spaceing inbetween trees in South East Asian forests is greater than that of African forests and forests in the Americas, which went on to give this as a possible explaination for the high numbers of flying or gliding animals in the South East Asian forests. But in the spiders case instead of trying to glide or parachute to such a far distance they evolved to save the effort an just bomb the hell out of there?

Anyone any thoughts on this or is this just a load of old cods wallop?
Cheers
Chris

P.S. Sorry if this is a repeat read for you!

[Nick L]

My guess would be aerodynamics. I don’t have a vast knowledge of Ts but aren’t the ‘bombers’ you quote generally large, long-legged with short hairs on their legs and by comparison the ‘gliders’ smaller, shorter-legged and ‘fluffy’ with longer setae on their legs? Maybe the ‘gliders’ glide/parachute because they can whereas the ‘bombers’ would not be able to effectively glide so instead legs are drawn in to protect them from damage. Studies have been done on arboreal caterpillars and hairy ones tend to fall uncurled whereas hairless ones tend to curl up into a ball.

[colin haris]

While we are on this subject, could anyone tell me if all arborel tarantulas can jump? Or are there exceptions?

[Chris Sainsbury]

Hi Nick
Well its a theroy at least and as good as any other I have heard. The only problem I have with it is that I am informed that species of Poecilotheria also do the parachute thing, but to my mind they are often larger bodied and often have longer legs than some of those South East Asian arborels. They also don't have any extra long setae on the legs at least none that I think you could say would help.
On the other hand when you look at the tarsus on the likes of Cyriopagopus sp. and especialy that of L. violaceopes the scopula (is this the right word) is very wide or large, which to my mind would help rather than hinder a kind of parachute effect, so why not use it?
Very interesting what you say about caterpillars and maybe this is partly the reason.

@Colin. Yes they can indeed jump short distances. Nothing in the same league as jumping spiders but they can jump, mainly in a downwards motion from say one branch to another if they need to, in mainly an escapeing from a percieved danger sort of way.

cheers
Chris

[KJ Vezino]

I am informed that species of Poecilotheria also do the parachute thing

That's why they are called parachute spiders. At least according to this document:

Common names of South Asian theraphosid spiders.
Zoos’ Print Journal 19(10): Molur, S. and M. Siliwal (2004).

http://www.zoosprint.org/viewPDFFile.asp?fname=1657-1662.pdf&typ=jnl&Imonth=10&Iyear=2004

[colin haris]

@Colin. Yes they can indeed jump short distances. Nothing in the same league as jumping spiders but they can jump, mainly in a downwards motion from say one branch to another if they need to, in mainly an escapeing from a percieved danger sort of way.

cheers
Chris

Hi Chris

I knew that most arborels can jump, my question was can they all jump, or are there any arborels that can't? ( a Woody Harrelson of the arborels)

[Paul Behan]

I would love to see my Avics jump, I never have done and may never do so I guess.

[colin haris]

I would love to see my Avics jump, I never have done and may never do so I guess.

Hi Paul

My first T was a sling Avic and I had no Idea they could jump, untill my little guy vanished from my hand and instantly appeared on my upper arm! The reason I bought her was to get over my fear of spiders, instead I nearly had a heart attack! that was a set back for the Colin/spider relations for a while longer...now I love em!

[James Box]

careful what you wish for...my versi slings completely and inconsiderately ignore the BTS no handling advice and come right out almost everytime i open their tubs! then they jump all over the place!
it's an immensely cute nightmare
but i digress from the topic, sorry!

could it be that the Poecilotheria use the parachuting technique because they are heavier than the arboreals that cannon ball? so if they were to cannon ball, they might splat?
but yeah a bit strange not to have the setae to aid the parachuting effect on top of that, and strange of the "cannon ball spiders" not to make use of their own aerial breaks.