power feeding pros and cons?

[Code Monkey]

Nothing personal, like I've said before, I thoroghly enjoy your comments and opinion.

Something to consider is you might not always be right on everything.

This isn't about me being right or wrong, it's you *not* pointing out a logical fallacy and then becoming a smartass about *not* doing it. If I say that tarantula venom possesses extensive proteolytic activity and you call me on it, hooray, you'd have caught me in an error. I've been caught in errors before and I owned up to them without a fuss. I am the first person to admit a genuine error believe it or not.

However, in spite of whatever existentialist world you live in, the rest of the scientific community is well satisified with the lack of consciousness in the arachnids. So, while you are in the most spectacularly pathetic trial lawyer sense accurate in making your statement that we dont KNOW that Ts don't feel pain, you would also have to be the OJ jury to buy your statement as more than trouble making and a desperate hope to avoid being convicted. I don't KNOW that you exist, but the scientific method and a combination of inductive and deductive reasoning allows me to conclude that the odds that you are merely some hallucination of my fevered imagination are so slim as to be 0. Similar situation exists for the tarantula feeling pain. We've mapped out EPSPs in invert nervous systems to the point that you can spend lifetimes analysing them (and many have and are) and the objective conclusion is that there is nothing going on there that appears to be suggestive of anything more than basic functions. Based on current knowledge, with a good reason to assume that current knowledge is pretty good on this subject, it is illogical to conclude that chances that tarantulas are conscious is anything great enough to be different than 0 for all intents and purposes. So, for you to hop up and down like you just discovered cold fusion over what really belongs in a philosophy discussion, not a scientific or even a forum Q&A like this, *is* pathetic.

And, btw, the 'virtual ignore' does not mean I won't read or respond, it's that I will no longer hold out hope that you have anything that will actually be worth my reading.

 

[Professor T]

. The invertebrate focused classes consider it a patently obvious fact that lifespan is tied to instar number and that instar number is tied to metabolism.

Code Monkey,

Your training must have been better than mine. In my graduate programs we didn't call it "patently obvious facts", we called it a hypothesis.

Then we would test that hypothesis. For example, a nice grad experiment might be to take a single species of T and keep all conditions constant except amount of food. Make sure you have a large sample size. Then you could follow their instar numbers and mortality rates. That would be a nice PhD dissertation, and you could take your time because it could take a decade.

However, if you want to pass, don't make any conclusions about G. rosea if you use A. versicolor populations. That would be like comparing apples to SUVs.

Maybe zoology courses are rare in VA, but they are not very rare in NY, FL, and KS where I went to school and taught. I'm taking 30 of my students from a wildlife management course I'm teaching to Costa Rica this spring break. Does your school ever leave VA? Want to buy some Costa Rica shade grown coffee? It saves the rain forest and helps my students go to Costa Rica. Only $10 per pound. So far, they've only sold 800 lbs. :}

Your pal,
Professor T

 

[Professor T]

I've been caught in errors before and I owned up to them without a fuss. I am the first person to admit a genuine error believe it or not.

Could you provide a link to one of your 3,091 posts where you admit you were wrong? I thought I read all your posts, I 'm a big fan, I must have missed that one.

You have untested hypotheses that you call facts. The more you learn, the more you realize how little you actually knew. This will come to you in time.

If you want to call something a fact that is really a currently favored hypothesis, thats your problem. I'm finished pointing that out to you, its no longer something that I feel I can be productive with. Either you don't get it because you're not trying to get it, or you get it but are unwilling to admit it. Either way its not something productive to continue for either of us, we're just going around in circles.

 

[Code Monkey]

Your training must have been better than mine. In my graduate programs we didn't call it "patently obvious facts", we called it a hypothesis.

:wall:

You would not have called it a hypothesis *unless* you were trying to get a paper out of it. The reason it can be concluded as "patently obvious fact" is that it always holds. People determine the ideal growth chamber regimen to keep their parasitoids in sync with the target organisms, when production becomes the focus, the alter the regimen to optimise speed, etc. There isn't anyone seriously asking themself with each and every species, "Hmm... even though every other invert that we've ever looked at has a faster development time to adult hood and a consequently shorter life when we increase their metabolism through higher temperatures and food, I'd better write that grant to prove that it works for *this* one as well".

Granted, I will admit to you that this would at best rise to a theory rather than 'fact' since as we both know genuine scientific *facts* are few and far between, it's the very nature of science. However, I am tired of your nitpicking because it's not on anything of merit. It's no more good science or good hobby husbandry to give arguably incorrect advice based upon the lack of a proven specific for each and every species than it is to wildly speculate from the specific to the general. There is a balance that is in between that takes what very general trends you can safely assume apply across the board, and the faster metabolism = faster development = shorter lifespan can be applied in that manner.

Other than turn this into a "Let's get CM to go over the definition of hypothesis, theory, & fact as they apply to a journal article versus a web forum" all you did was again decide to play devil's advocate in, I think, an irresponsible manner.

So fine, here you go: if this web forum were a peer reviewed, scientific journal published in the United States, my use of 'fact' for the widely observed and widely held principle of correlation between metabolism and lifespan would have been corrected and/or rejected by the editor. If this were such a journal, I would be wrong for the use of that term and instead of should have been clear that this is a theorem of physiology and not a scientific fact. Furthermore, if this were a primary literature journal, I would be disallowed from making any inferences to other species not directly studied in the course of the research that is being published.

However, since the point of this web forum is to disseminate good information to people not jumping through hoops for a graduate degree, I am confident in saying it is true that shortening intermolt periods in tarantulas will result in some shortening of their lifespan as such a conclusion is consistent with a vast realm of hard, primary literature. Furthermore, I am confident that me forming just such a specific hypothesis for a masters project entitled 'Quantification of environmental factors on development rate in P. murinus' would be accepted without any protesting by the faculty because each of them would accept on principle that what I was setting out to prove in the specific was supported by general theory and therefore a good experiment.

However, this is not such a journal, and if I ever had the misfortune of talking to someone in a casual conversation that decided to nitpick everything said as though it were such a journal I might have to abandon my generally pacifist ways.

 

[Code Monkey]

Could you provide a link to one of your 3,091 posts where you admit you were wrong? I thought I read all your posts, I 'm a big fan, I must have missed that one.

Didn't take very long at all.

 

[Professor T]

:wall:

You would not have called it a hypothesis *unless* you were trying to get a paper out of it.

<SNIP... man, that was a big quote. -MrI>

King of Nadkicking,

LOL, what a great, well thought out, intelligent response, and there is not a drop of sarcasm in my statement. Your point was excellent and well stated. You are amazing when you want to be, that summerized our exchage in a nutshell. A++, I bet you're an amazing student and your teachers and peers love your passion. Have a great evening.

 

[Anansi]

Wrongo, there is a wealth of data on life forms that draw the correlation between metabolism and temporal lifespan. If increasing their metabolism didn't shorten their lifespan they'd be the first organism to not display this trend. No, no one has specifically shown this for tarantulas (and you never will see this data for tarantulas as such a study would never be funded) but it's been looked at across species thoughout the animal kingdom and it's a pretty damn consistent correlation

Yes code monkey but how can you generalize the evolution of tarantulas to species throughout the animal kingdom?...tarantulas are one of the only organisms to remain relatively unchanged for millions of years...they have followed rarely any patterns of wider arthropod evolution...I think the fact that their manidibles/ chelicerae remain more vertical rather than horizontal (which is what evolution has selected for in a majority of other species) illustrates the point that tarantulas may be an anamoly and therefor not applicable to your analogy...Also, they are poikilothermic, so to imply we could change their metabolism by simply raising the temperature, when they've lived in chaotic environments for millions of years is a bit far fetched...

 

[ORION_DV8]

Powerfeeding may or may not shorten lifespan, but it does in fact shorten the time between instars, we can agree on that. That is the only real measure we can take feasibly due to the lifespan that T's have. All that can be said for the rest of the argument IMHO is to restate that there are so many confounds that it would be an impossibility to test this hypothesis. All one could do is to say that in captivity this is what was observed. Besides whats to say that one T will not mature faster than another regardless of powerfeeding i mean i realize that certain constants do exist but one T may be experiencing less stress than another in the experiment. Certain animals are just more resilient and vigorous regardless of powerfeeding, it is the basic Darwinian principle. There may be some that mature faster than others from one eggsac and these will pass the genetic material before all others and have a better chance of securing resources. I may be up the creek with this though.
ORION

 

[SubZero.nl]

Powerfeeding may or may not shorten lifespan, but it does in fact shorten the time between instars, ...

what is "instars"

sorry to interrupt this scientific thread with a newbie question :8o

 

[Code Monkey]

Yes code monkey but how can you generalize the evolution of tarantulas to species throughout the animal kingdom?...tarantulas are one of the only organisms to remain relatively unchanged for millions of years...they have followed rarely any patterns of wider arthropod evolution...I think the fact that their manidibles/ chelicerae remain more vertical rather than horizontal (which is what evolution has selected for in a majority of other species) illustrates the point that tarantulas may be an anamoly and therefor not applicable to your analogy...Also, they are poikilothermic, so to imply we could change their metabolism by simply raising the temperature, when they've lived in chaotic environments for millions of years is a bit far fetched...

Jaysus, did you just not follow any of the nitpicking contest between me Prof. T? You are _wrong_ and a just a bit on the dangerous side if you thing chelicerae arrangement allows them to violate basic physiology. "Ooh look, this beetle is blue with red, purple, & green spots, I've never seen that before, I'll bet it can travel through time!"

Also, for the record, evolution selected for their chelicerae orientation as well. Fossil evidence suggests that earliest proto spiders were midway between the two groups of spiders that exist today. And far fetched that alterations in temperature change the metaboloism? You aren't worth arguing with, go back to high school. Professor T may have been an annoying PIA, but at least he had some technicalities on his side as opposed to a gross misunderstanding of what being ectothermic had to do with an animal. For the record, for every 10 degree change of an animals internal temperature, metabolic rate doubles (or halves if temps are going down) unless the temp change also happens to cause the enzymatic processes to stop and they die; but far fetched, it's not even close to far fetched, it's basic chemical kinetics. :wall:

 

[Code Monkey]

Powerfeeding may or may not shorten lifespan, but it does in fact shorten the time between instars, we can agree on that. That is the only real measure we can take feasibly due to the lifespan that T's have. All that can be said for the rest of the argument IMHO is to restate that there are so many confounds that it would be an impossibility to test this hypothesis. All one could do is to say that in captivity this is what was observed. Besides whats to say that one T will not mature faster than another regardless of powerfeeding i mean i realize that certain constants do exist but one T may be experiencing less stress than another in the experiment. Certain animals are just more resilient and vigorous regardless of powerfeeding, it is the basic Darwinian principle. There may be some that mature faster than others from one eggsac and these will pass the genetic material before all others and have a better chance of securing resources. I may be up the creek with this though.
ORION

Since this shortened lifespan has been shown time and time again in Ts with males (or have you never seen the breeders who will keep males at lower temps with less feeding to slow their maturation and subsequent death, or speed them up by raising temps and food?), you are simply "up the creek" on this one. And if you still hold out that females magically live longer, I'll tell you what: Get yourself a couple of avic female slings. Go raise temps and food to get the one female to her maturing moult in 14 months, leave the other one at room temp such it takes 24 months, they will both be roughly at the same point in terms of their instar number. Now, since we know that tarantulas and scorpions along with all of your arthropods have a relatively fixed number of instars (admittedly, no one knows what the spread is something like a B. smithi or A. chalcodes - that's why I went with Avicularia ;P), even if we magically assume that each mature female, independent of food and temp, only moults once per year from that point out are you going to seriously try to side step the obvious conclusion that the one that got to maturity in 14 months is not going to live a shorter time span the one that took 24 months?

EDIT: Also, you are right in your schpiel about variance and such existing within a population, it just doesn't have anything to do with particular subject. Sure, you can't point to Bob's spider that is powerfed and automatically conclude it won't live as long as Jay's spider that isn't since there is variability. However, if Bob were to somehow duplicate his spider such that he had genetically identical spiders, and he then raised the metabolic rate of one versus the other, it would be pretty easy to predict which one should live the shortest time (barring something odd like nematodes or a fall). The raising or lowering of metabolism for any particular spider is going to alter that individual's potential lifespan based upon it's particular genetic makeup. So, you were sort of on the right track (as opposed to Anansi a few posts back that was off hitting golf balls into the swamp).

 

[TroyMcClureOG82]

Regarding alterations in temperature affecting the metabolism of poikilothermic organisms: I don't think Anansi was trying to argue that the metabolism of tarantulas won't increase with an increase in temperature. That is what code monkey would call a scientific fact. His point was that tarantulas have survived for thousands of years through many climatic changes. Even today they survive in varying climates. There is no evidence that suggest that modern tarantula species in cooler climates live longer live than species living in warmer climates. There is also no conclusive evidence to suggest that tarantula species lived longer lives in cooler climates in the past.

I will admit Code Monkey, I tend to agree with you. You provide an interesting and well thought hypothesis connecting metabolic rates with life expectancy of Ts. It is still nothing more than an untested hypothesis that can not be supported without using the scientific method, and you are attempting to use rhetoric and conjecture to "prove" your point to others. There are many hypothesis among the scientific communities that have not been tested. Many are sound hypothesis that may very well some day be proven, but without any solid evidence the argument will continue forever. Even after extensive research and conclusive evidence/data/experiments there will always be somebody that will argue against you.

 

[Code Monkey]

what is "instars"

Each particular moult is an instar. For instance, the non-feeding but free moving post-nymph moult out of the egg sac is the 1st instar. When it moults again and becomes the free living, free feeding sling that gets sold or otherwise distributed, that's the 2nd instar. When that spider moults again, it's a 3rd instar, and so on & so on. Arthropods are marked by a fairly fixed pattern of instars relative to their life cycle.

 

[Code Monkey]

Regarding alterations in temperature affecting the metabolism of poikilothermic organisms: I don't think Anansi was trying to argue that the metabolism of tarantulas won't increase with an increase in temperature. That is what code monkey would call a scientific fact. His point was that tarantulas have survived for thousands of years through many climatic changes. Even today they survive in varying climates. There is no evidence that suggest that modern tarantula species in cooler climates live longer live than species living in warmer climates. There is also no conclusive evidence to suggest that tarantula species lived longer lives in cooler climates in the past.

Well, I think you're putting words in the mouth of someone I've had to correct more than once

And even if that were the words he meant to type (as opposed to typing), he'd still be wrong because nobody argued this as an apples an oranges kind of thing, which is what your particular interpretation of his post requires.

I will admit Code Monkey, I tend to agree with you. You provide an interesting and well though hypothesis connecting metabolic rates with life expectancy of Ts. It is still nothing more than an untested hypothesis that can not be supported without using the scientific method, and you are attempting to use rhetoric and conjecture to "prove" your point to others. There are many hypothesis among the scientific communities that have not been tested. Many are sound hypothesis that may very well some day be proven, but without any solid evidence the argument will continue forever. Even after extensive research and conclusive evidence/data/experiments there will always be somebody that will argue against you.

So now, although even the biggest nitpicker of all, Professor T, has properly chastised me in *our* discussion for an irrelevant use of a term on a web forum, you're going to suddenly wax all scientific yourself about untested hypotheses, puhlease

While it may be technically untested in the specific of tarantula species, it has been seen so often across the animal kingdom, invert and vert, that no one runs about testing such a thing. Yes, it may be nothing more than a 'scientific assumption' to hold that this principle *also* holds for Ts, and that there is a 10 time power-ball winner's chances that Ts somehow magically avoid the correlation between lifespan and metabolism that effects everything from a mushroom to us, but it would be a fool's bet to take that chance. Let me put it this way, we haven't proven using the scientific method that not feeding T. blondi slings will kill them, would you seriously be in this thread arguing if the point was that I claimed that you had to feed your T. blondi to keep it alive? We haven't proven using the scientific method that using a Macintosh G5 tower to bludgeon chihuahuas will kill them, but I'll bet you'd accept that deduction from other applications of the scientific method without this sort of semantical whining. Heck, let's even put it another way, if it wasn't *me* making that post and that P_T had already got me to capitulate a semantic point within this thread, what are the odds you'd be doing the whining?

To go back to my one post to Professor T, if I went to my committee meeting and proposed to *quantify* the effects of environmental variables on P. murinus development, they would be happy. If I said I was going to test to see if the environment affected the development of P. murinus they would look at me as if I'd just proposed a project that involved counting the legs on insects. Sure, we don't know specifically how much the change is; we, however, do assume based on good science that change is there in the first place.

This is a hobbyist board, keep the sort of crap I expect in my committee meetings away from them if you don't mind.

 

[TroyMcClureOG82]

Slowing down the metabolism of some organisms will kill them. Speeding up the metabolism of other organisms will cause them to thrive. A human with a slow metabolism is in worse shape than one with a faster metabolism. I have never heard anything about skinny people with fast metabolisms having shorter expectancies than fat asses with slow metabolisms. All you have done is continue to spew more rhetoric and conjecture. Not only are you making unfounded claims, but you are generalizing. These are both looked down upon in the scientific community. Just take a look at the current state of taxonomy that was done by people who generalized based on shared characteristics and assumptions compared with modern gene mapping discoveries.

 

[Code Monkey]

Slowing down the metabolism of some organisms will kill them. Speeding up the metabolism of other organisms will cause them to thrive. A human with a slow metabolism is in worse shape than one with a faster metabolism. I have never heard anything about skinny people with fast metabolisms having shorter expectancies than fat asses with slow metabolisms. All you have done is continue to spew more rhetoric and conjecture. Not only are you making unfounded claims, but you are generalizing. These are both looked down upon in the scientific community. Just take a look at the current state of taxonomy that was done by people who generalized based on shared characteristics and assumptions compared with modern gene mapping discoveries.

Oh whatever, you raise/lower most endotherms they die because their biochemistry doesn't function except at a vary narrow range of temperatures. You raise lower ALL the ectotherms and their metabolism does change by the 10=2X I described, there's even a common name for that principle that escapes me at the moment. P_T was merely trying to make a point, you're just being stupid at this point.

 

[TroyMcClureOG82]

"If I said I was going to test to see if the environment affected the development of P. murinus they would look at me as if I'd just proposed a project that involved counting the legs on insects. Sure, we don't know specifically how much the change is; we, however, do assume based on good science that change is there in the first place."

Sounds like you just admitted after all your rambling and babbling that in fact we can not say that there will be any SIGNIFICANT change in the life expectancies of Ts with increased metabolism and feeding and to say there is would be adding even more rhetoric and conjecture to your "good science".

 

[Code Monkey]

Sounds like you just admitted after all your rambling and babbling that in fact we can not say that there will be any SIGNIFICANT change in the life expectancies of Ts with increased metabolism and feeding and to say there is would be adding even more rhetoric and conjecture to your "good science".

I said that back in my first post to this thread, but I guess a nitpicker like yourself would have missed that

EDIT: OK, it was the second post: http://www.arachnoboards.com/ab/showpost.php?p=338356&postcount=13

And, btw, thanks for your own misuse of terminology, there would clearly be every reason to believe in a significant difference (you know, the whole P<0.05) between some particular set of variables or no one would approve the project. Don't act like you know what you're talking about when apparently it's nothing more than a "hey, let's see if I can tag the monkey game" day for you.

 

[TroyMcClureOG82]

"And, btw, thanks for your own misuse of terminology, there would clearly be every reason to believe in a significant difference (you know, the whole P<0.05) between some particular set of variables or no one would approve the project. Don't act like you know what you're talking about when apparently it's nothing more than a "hey, let's see if I can tag the monkey game" day for you."

That would assume that there is going to be any difference at all. Plenty of projects are funded without any knowledge to whether or not there will be any difference found at all. Some students in my class are currently using digital recording anlaysis software to determine whether or not there is any difference in songs between a particular bird species in different localities. Prior to their research it was assumed there was no difference (the human ear could not hear one). Their research found there are specific differences between localities. I met a guy today that mapped gene sequences of microbes found on the mucus of corals. Nobody knew anything about this prior to his research at Scripps. 72% of the bacteria he found had never been sequenced and were found nowhere else in the ocean. He had similar results with phages. Prior to his research nobody had any reason to believe microbial diveristy was any different from the surrounding sea water.

 

[TroyMcClureOG82]

" Yes, it may be nothing more than a 'scientific assumption' to hold that this principle *also* holds for Ts, and that there is a 10 time power-ball winner's chances that Ts somehow magically avoid the correlation between lifespan and metabolism that effects everything from a mushroom to us, but it would be a fool's bet to take that chance"

You call me silly for saying:

" A human with a slow metabolism is in worse shape than one with a faster metabolism. I have never heard anything about skinny people with fast metabolisms having shorter expectancies than fat asses with slow metabolisms"

Instead of giving me any evidence that supports your claim that our life expectancy is decreased as our metabolism increases