Overfeeding?

[Neil Martin]

I have heard that it is possible to overfeed Tarantula's?

My reason for asking is that I have recently started feeding locusts to my 2 year old Smithi (which molted 2 weeks ago) instead of brown crickets and it is currently taking 1 a day. They are almost the same size as the spider so I can't really see where it is putting it all?

It even ran up the glass last night to get one from under the lid (quite amusing to watch it take 1/2 hour to get back down, slipping on it's own venom with a tentative "foothold" on the cork bark), so I assume that it has a large appetite for them?

What are the consequences of overfeeding (if any) or should I keep putting them in until it stops taking them?

PS: Does this apparent overtly aggressive hunting (it also follows them around the tank rather than just waiting in it's lair) indicate that I may have a male spider?

[Joseph S. Gaglio MHS]

Back in the late 90's I was in contact with a biology grad student who was part of a group doing research on tarantula nutrition. Although the papers were not ready for the public at that time, he indicated that preliminary findings suggested that "Power feeding" reduces life span, interferes with the animal's immune system and can have an adverse effect on reproductive success. The papers were supposed to be ready for publication very early the next year and were going to include some studies on inbreeding and the nutritional needs of captive tarantulas, especially with respect to feeding your crickets. Unfortunately I lost contact with that student, however, my correspondence with him only topped off an idea already spawning in my tired old brain. I could have put it all together before if I was "thinking outside the box". In the past I have advocated heavy feeding but a series of events, culminating in with the above mentioned correspondence, completed some connections in my head and have caused me to rethink the issue.
It started when my daughter's African bullfrog died. I began to think about the effects of a steady diet of mice on the frog's kidneys. Although they are predatory, their natural diet would include a high percentage of insects, small reptiles, fish, and other amphibians. All of these items are very significantly lower in fat (just for one example) than mammals, especially captive raised mammals. Humans who are overfed on diets that are similarly rich develop a variety of degenerative diseases, including compromised immune systems and other life threatening conditions. We have seen the results of too rich a diet on human children. An alarmingly high number of youngsters killed in Viet Nam were already showing cardiovascular effects previously not seen until late adulthood.We have also seen what happens to Pacific Islanders who adopt heavy Western diets; obesity, diabetes, arteriosclerosis, auto immune irregularities, etc. I have seen some articles which point out that many captive reptiles are overfed, leading to various degenerative diseases. It is widely recognized that omnivores fed on a diet rich in large quantities of protein grow faster to maturity but have shorter life spans.

While tarantulas are not men or lizards, it seems to me that when we see these same effects in mammals, reptiles, amphibians and fish, we really need to keep our eyes, and minds, open on this issue. Quite a few of the spiders I've seen in captivity could only be referred to as obese by any standard. Some can barely keep their opisthosoma off the substrate and would very likely be injured in even a very short fall. Wild caught tarantulas, even those from "bug infested" tropics, are never found with the huge abdomens so common to captive animals. Unlike some of the other ongoing disputes , such as the *Best* substrate for captive care, I think research will eventually produce something pretty close to an answer on the nutrition issue, if we can get the research done. That's exactly why we should do research. We can come up with all kinds of logical explanations and lines of thought in any situation. Some of them will be incorrect and some are WAY off base. Just because something makes sense, that doesn't mean it's true. Controlled studies are the only way to begin to get a handle on these things. Even then there will be serious difficulties. One of the problems is the life span of some tarantulas. Who's going to be around for 30 - 40 years to check the effects of feeding on an Aphonopelma? It's an even bigger problem when we look at inbreeding. That's why I have been seeking information about the fastest maturing species. I don't think I will have the time to observe four or five generations of a tarantula that take 5 years to mature. Even if someone did he would run into all kinds study design problems. How many P.ornata does it take to provide a representative sample size? If it were only five or six pair he would need another five pair for a control group. Now he has to feed all the offspring of ten or eleven pair of wild caught ornata. What would he feed them? Crickets only to reduce the number of variables? How about a varied diet to simulate natural conditions? Do we have actual field observations to tell us what P.ornata eat during the course of a year? Having spent quite a few years in South East Asia I'd say it's very likely that their diet changes drastically from the rainy to the dry season and there are probably times toward the end of the dry season when they don't get much of anything at all. The number of unanswered questions is staggering and the time and money involved is far beyond what any individual could handle. I'd like to see the ATS and BTS funding some studies in this area.

I maybe criticized for fear mongering based on speculation and very preliminary results but I choose to err on the side of caution until we can get more conclusive data. That's what being a scientist is all about. If there are obvious design flaws in the research the results may be discredited. If the researchers "have a stake in the game" (i.e., the American Dairy Association funding research on why it is good for adults to drink milk) the results might merit VERY careful scrutiny. However, barring these problems, good studies should give us something to go on, even though a lack of replication may keep some die hards in the old school. We will see. In the meanwhile I will stake my bet on the "natural" side and keep my bugs at a weight closer to what would be found in the wild.
Another factor to be considered when we talk about feeding is the mindset of the hobbyist. Most of us really enjoy watching our pets eat. This is no problem for someone with 30 or more animals. I know I used to have difficulty just getting to my 300 or so spiders and s'lings on a weekly basis. I gave the s'lings priority so on many an occasion some of the the big guys had to go two weeks or more without tending other than the cursory inspection I did nightly to insure there was nothing getting out of hand anywhere. On the other hand we have someone with just a few spiders who is likely to feed often. Stan Schultz does some very rough calculations in his book (Schultz and Shultz, 1998, p.49) and surmises that full grown tarantulas likely need no more than 6 - 8 crickets per month and that some will become obese even on that amount. If research does suggest (and that's all this kind of research can ever do is suggest) that overfeeding is detrimental, it will take a lot of restraint for some folks. I saw a similar problem when I was involved with the art of Bonsai a number of years ago. People with just a few trees often watered, pruned and fertilized them to death. A bigger collection was self limiting with respect to the amount of time that could be spent daily on a single tree. With all this in mind I guess there is a simple solution to the problem of overfeeding. We all just need to go out and get more tarantulas! . (I originally posted an earlier version of this to the web back in '99)

[clarkemcrobb]

Id like the opportunity to study something along those lines. its fascinating. My very uninformed opinion, based on logic is that the truth could lie either way:
A: there is no such thing as overfeeding, an instinctual animal will build up and store the appropriate amount of energy to molt/reproduce etc, and it will eat when it next needs to.
B: Overfeeding is a serious lifespan threatening factor.

I believe in the latter TBH, like the gentleman in the post above me stated, comparative studies of of humans, reptiles etc would suggest that being 'overweight' leads to serious problems.

But like he said, someone like me, who has two spiders so far in his collection, may overfeed, as the feeding is beneficial to the entertainment of themselves, yet they dont have a large enough collection to properly study the effects of overeating. Whereas someone with a large enough collection to study the effecs of overfeeding, may not possibly be able to overfeed and monitor, several hundred pets for many, many years with complete and utter dedication.

Unless a decent study is done, all we have are analogies and logic.

[Ray Hale]

Many years ago I introduced a reptile enthusiast friend of mine to tarantulas. He had insisted that I get into keeping snakes but having tried over the years I constantly return to my spiders.Being new to the hobby he went along the road of keeping the biggest he could find. ( he was the curator of a zoo and wanted to exhibit them). He kept goliaths and fed them mice. I advised him against gut loading his spiders but he had made up his mind and feed them he did. It had to be said that his spiders were big but they were also very short lived, achieving maturity very quickly and death even quicker. Overweight spiders often suffer when moulting and Ive never seen a fat spider in the wild. I often use the analogy of a tomato. Feed it every day and keep it hot and it will get to huge size but its shelf life and quality are greatly reduced. Just a thought!

[Neil Martin]

Thanks all for the replies.

Ray, I will heed your advice and cut down on the feeding as the spider seems to have no "self regulation". Perhaps a locust every other day with crickets in between, or does even this sound like too much?

As an experiment I fed it a cricket last night which it took immediately. I am also looking after a friends spider which is pretty much adult and seems to have stopped eating and may be ready to moult. Anyway when the locust climbed onto it's back and the spider ran off, I decided to remove it and for convenience threw it into my spiders tank - It could hardly have finished the cricket when it took the locust!

This morning it has a very extended abdomen and I feel this one may cause itself problems if I keep providing the "ammunition"?

[Neil Richardson]

For feeding mine, spiderlings get 1-2 roaches a week, dependant on the specimen and it's eating habits.

Adults get 1 roach every 2 weeks, unless they have been mated, in which case they get as many as they will take, once a week.

[Ray Gabriel]

This is a good thread,

I discovered that after my collection grew, i had less time to feed all my spiders on a weekly basis, (only rearing and breeding stock and mated females were fed on a regualr basis), and as i had less time to feed them all (dont worry they all got fed) but as the feeding went down the comparitive overall death rate went down also, and i am not the only person to have noticed this.

Spiders are opertunistic feeders so dont get fed at 5PM every Friday in the wild, i think that in captivity missing the occasional feed is not a problem (except with spiderlings), and the spiders benefit from it, so does the bank balance :P

So dont worry about going away on holiday just make sure they have water.

Over fed Tarantulas with thier abdomens dragging on the ground are not healthy tarantuals, i have yet to find a tarantula in the wild with a huge abdomen, most of the spids i have found in the wild would be considered by pet keeping standards as "starving", but boy can the move fast.

There is also something in the BTS Exhibitions best specimen awards about over fed spiders (which i fully agree with), lose out in the judging (sorry guys) maybe a BTS Commitee Member can elaborate on this, as there appears to be more new members on the site, and proper feeding of thier spiders is a good way to help them realise they can glean information from the website.

Ray

[Andrew Ferguson]

Prior to my smithi recent moult, it rarely ate anything. So when it moulted I knew it would be hungry. Three days after the moult, the fangs looked dark so I tossed in a very small cricket about 7mm in length. Gone!
After a week I tossed in a much larger (15mm) cricket. Gone too. It was finally a joy to see it eating (not in a macabre way) and acting like a tarantula (in my opinion). Later in the week I thought "would it take another?" So I tossed in another small one. Gone. Surely it wouldn't take another. Yup, that went too. All in all, since its moult (just under a fortnight ago) it must have taken 5 little 'uns and a large 'un. However something prompted me to do a search on the forum for over eating and I found this thread. I thought I'd give it a bump as there are a few newbies (myself most definitely included!!) who may benefit from it.

p.s. Gloria will be going on a diet for week and a half

[Peter Lacey]

Thanks for bumping this thread Andrew, a great read.
I think its so much easier to feed more than necessary when faced against the worries of not feeding enough, despite what we may be told. Apart from the slings, I try to restrict to 2 crickets a week but some receive 3, they're almost always consumed within 24 hours and to the most part within half an hour. Only one of my Ts, a boehmei, has ever killed food items in the enclosure without eating, almost as if to say, that I'll teach you to run around annoying me
Taking a quick look, all the Ts I can see at the moment have rounded abdomen which suggests they don't need feeding, despite tomorrow being feeding day. As I'm soon to take a weeks break I'll probably give each of them 2 crickets within the next week and see if I can see any signs of change once I return. Of course I'm not expecting anything within 1 week but on my return I may resist the temptation to feed for a period after that. Will the T be more active, more of a hunter, more responsive to disturbances? Its a worthwhile study if I can only resist feeding.

[matthew spooner]

i used to feed my Ts regularly but after taking note of some advice i was given by Andrew Smith, i now only feed my Ts 2 locusts per month, they are quite happy with this and i expect their life expectancy has gone up too