tarantula intelligence

[smokejuan]

Tarantula Intelligence questions

OK. I am not saying either way about a tarantula's ability to do anything other than breath and eat. First, so far 99% of my escape's have all crawled from high places down and over obsticles to get to the closet. These were all female Tarantulas that have done this and I geuss thuss far arrid or terestrial tarantula's. Saying that, When I breed my tarantulas I always move the tanks with the perspective females to breed and the male to the floor for ease of controlling the situation. I have been mating a pair of B. smithi's for about a month and a half once a week. This last instance yesterday was unusual. The male was cimbing the side of the tank wanting out and I saw a recent sperm web so I figured he was ready to breed. Now I open ( take the lids off) both his and her tanks which where about 3ft apart. I take my arachno elevator (angled plastic long handled spatula) and coaxed him on to it and carried him over to her tank and put him in. After feeding others for 30 minutes neither of them moved an inch. Company came over and got me destracted for an hour or so. I remembered about them and ran back there expecting to go on a great spider hunt for both but instead found her still in the same place and that that he had crawled out and down from of her home accross the floor and back up the side of his and back in and was inside the hide. I have only had him about 2 months so I don't feel he is overly attached to his new surroundings. What I am asking is what compelled him to return or know how to return to that tank 3 ft away and risk climbing glass to get back in? I figure with all the brain power here we could come up with a logical explanation about the driving force to that lead him back.

 

[Code Monkey]

I figure with all the brain power here we could come up with a logical explanation about the driving force to that lead him back.

Two months isn't long enough to reinforce whatever it is that tarantulas use for locale cues? Ants lay down a foraging trail over 30 minutes or so, are able to follow it religiously so long there continues to be positive reward for following it and they are renewing it, then abandon it when the food source dries up, and this whole cycle all takes place in as little as a few hours.

Although poorly studied, tarantulas must be capable of some fairly sophisticated chemotaxis or wandering males would never succeed in the first place. It is no great leap to assume they can recognise their own chemical trails or "smell" home so nearby. The nature of their ability to undergo such chemotaxis is what is poorly understood, but it's certainly been demonstrated, particularly in the case of males seeking females.

If I were to offer an explanation it would be that the male wasn't interested in breeding (still recharging the palps, the female is giving off some "no vacancy" cue, etc.) and simply went towards the most positve chemical gradient. Also, even if you assume that there isn't much in the way of chemical trails/cues in the space between the tanks, you weren't there to see what sort of exploration occurred. It wouldn't take but so much trial and error to encounter positive taxis stimuli and follow that.

 

[king7]

i remember seeing an experiment on tv a few years ago (was a long time ago and cant remember all the details so if anybody wants to fill them in) where they got so many spiders in a row (that use a web to catch flying insects ect) and each day they placed a fly in the same spot on the web.over time the spider reinforced that part of the web.surely this must be a sign of intelligence?

 

[becca81]

i remember seeing an experiment on tv a few years ago (was a long time ago and cant remember all the details so if anybody wants to fill them in) where they got so many spiders in a row (that use a web to catch flying insects ect) and each day they placed a fly in the same spot on the web.over time the spider reinforced that part of the web.surely this must be a sign of intelligence?

I also recall seeing something about this - but that was a "true spider," not a tarantula. I believe that true spiders are considered to be more evolved than tarantulas.

 

[Code Monkey]

I also recall seeing something about this - but that was a "true spider," not a tarantula. I believe that true spiders are considered to be more evolved than tarantulas.

Hardly, they've all been around the same length of time so how can one be more evolved? The bogus argument postulates the mygalamorphs are more primitive by virtue of their fang arangement. Fossil evidence shows that both fang arrangements are modifications of an ancestral form that was intermediary, each selected for what it does best. The "true spiders" have a nip and run approach, the mygalamorph grabs and holds, for each strategy the fang arrangement works best.

There is a lot more reason to suspect that tarantulas will have the greater learning capacity than most true spiders by virtue of their long lives. Of course, designing behavioral experiments with something that sits in one place for days at a time is not so easy.

 

[becca81]

Hardly, they've all been around the same length of time so how can one be more evolved? The bogus argument postulates the mygalamorphs are more primitive by virtue of their fang arangement. Fossil evidence shows that both fang arrangements are modifications of an ancestral form that was intermediary, each selected for what it does best. The "true spiders" have a nip and run approach, the mygalamorph grabs and holds, for each strategy the fang arrangement works best.

There is a lot more reason to suspect that tarantulas will have the greater learning capacity than most true spiders by virtue of their long lives. Of course, designing behavioral experiments with something that sits in one place for days at a time is not so easy.

Ah, ok. I don't recall where I heard the bit about how evolved each are, but it may have possibly been on TV (Discovery Channel, etc.)

I remember seeing something about the good eyesight of most jumping spiders and how their hunting capabilities (combined with good eyesight, etc.) proved them to be "the most evolved" of all spiders. I wish I could remember the name of the show or something else about it.

 

[Code Monkey]

I remember seeing something about the good eyesight of most jumping spiders and how their hunting capabilities (combined with good eyesight, etc.) proved them to be "the most evolved" of all spiders. I wish I could remember the name of the show or something else about it.

The salticids are definitely the most evolved in terms of visual recognition and sensory processing. But, when push comes to shove, they're just as much about hard-wired subroutines as any other spider. I really don't like the terms "more evolved" when pegging an entire creature. Certainly you can peg where something falls on the evolutionary chain, but anything alive today has just as much genetic heritage as anything else. If something hasn't changed significantly in 10 million years or whatever, it's because it's was already doing just fine in its particular niche and whatever selective pressures exist for that niche serve to reinforce their form rather than favor a different one.

Whenever you get someone talking about more recent forms being inherently better, you're dealing with an idiot who believes evolution is teleological.

 

[Code Monkey]

I think we need to go back to page 1 where Nerri asked "What is intelligence?", but it looks like the consensus seems to be an ability to learn, and if that's the case, yes, your tarantulas possess intelligence.

Inverts learn through two (three) mechanisms: Habituation, Association, and some by a form of Imprinting.

Habituation is when they learn to tone down or even ignore the most primary automatic response. An example is how they over time will not necessarily react negatively to you handling them or opening their cage lid.

Association is when they learn that one particular set of stimuli is associated with some other set of stimuli. This can be when they learn that the opening of their cage lid usually means fresh water or food is coming. It also occurs with spiders who are routinely milked for their venom, but in this case they associate rather minor interference with the electric shock and are much more likely to bite.

Imprinting is a form of learning that I know of no arachnid example, but many phytophagous insects are more likely to oviposit on the same kind of plant they were reared on. It's not a genetic cue because you can mix and match the eggs artificially and you find the adults heading back to whatever they wound up reared on by the crazy scientists.


A classic experiment with cockroaches demonstrating learning and the very foggy notion of our understanding their memory involves having a small plate that delivers an electic shock to one of the legs of a restrained cockroach. Eventually, the cockroach learns to hold that leg up for longer and longer periods (and if the negative stimuli is removed, it forgets to hold it up after a period of time as well).

Now, here's the neat part. If you decapitate a roach that has learned that it should hold its leg up as long as possible if it gets shocked, it continues this behavior. Somehow the memory is stored in the abdominal ganglion responsible for that leg. If you repeat the decapitation experiment on a roach that hasn't previously learned this behavior, the headless torso never holds it's leg up longer than the minimum interval proscribed by the basic avoidance behavior no matter how many times you shock it. Something in the roach's brain is necessary for learning to take place even though the memory is stored proximally at the abdominal ganglion.

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At any rate, all complex invertebrates possess some degree of learning capacity but the learning is generally dedicated to modifying hardwired behaviors. What is intellectually fascinating about our tarantulas is this: Evolutionarily speaking, it is generally believed that extensive learning is not favored because most inverts have such short, peril filled lives. There isn't time to learn because they essentially need to have a pre-written rulebook for anything and everything. If they needed to learn how to handle most things, they'd be quite dead before passing on their genes. Additionally, because so many inverts have such different niches during their life stages, learning is proscribed against, e.g. what good would it do a butterfly to store memories from being a caterpillar, or a mosquito its aquatic larval days?

Tarantulas, though, can live for several decades in more or less the same niche for that whole time. They make great candidates to have developed some form of long term memory and behavior modification from their learning.

 

[Gesticulator]

As humans, I think we just try to understand the world around us as only a human can . I don't think we have it in our own wiring to fathom how and why a tarantula conducts itself they way it does.