Vegetarian spider... what the hell?

[Third Eye Open]

This is just to weird. How does something like this happen?

Although this quote:

A tropical jumping spider that eats mostly plant buds has been identified, a new study says—making it the only known vegetarian out of some 40,000 spider species.

Contradicts this one:

Though the spider does occasionally snack on ant larvae, the bulk of their diet is plants, Meehan said.

Which would mean the spider is an omnivore and not a vegetarian, it still is very weird to me. How does a spiders fangs adapt to eat fruit?

 

[godless dave]

It doesn't seem that weird to me. Digestion of the food would seem to be more of a hurdle than the mouth parts.

 

[Steve]

This summer my 7yo caught a spider and put it in a covered aquarium. She fed it leaves and grass every day for a week, until she lost interest. She also made sure that it had fresh water to drink. It was still alive when I released it so this too must have been a vegetarian spider!

(Ok, sorry.... I expect that spiders can probably live for a week without feeding, or that there were bugs on the leaves)

 

[Dr. Trintignant]

I wonder:

I've read that one reason that spider silk isn't harvested is because they can't be bred easily in captivity (as is done with silkworms), since they tend to eat each other if in proximity. Perhaps this vegetarian spider would get around that problem? Spider silk could be a very useful material (although I admit that I like the spidergoat approach as well).

- Dr. Trintignant

 

[Floyt]

I wonder:

I've read that one reason that spider silk isn't harvested is because they can't be bred easily in captivity (as is done with silkworms), since they tend to eat each other if in proximity. Perhaps this vegetarian spider would get around that problem? Spider silk could be a very useful material (although I admit that I like the spidergoat approach as well).

- Dr. Trintignant

If this species is a Jumping Spider, it probably won't produce a lot harvestable silk, as it does not spin trapping webs (although possibly cladding for its lair, if it does keep one).

ETA - duh. Being herbivorous, it wouldn't use a trapping web in any case

 

[jasonpatterson]

I've read that one reason that spider silk isn't harvested...

It used to be harvested, but I don't know if it still is. I wouldn't know about this at all except that there was a spider silk 'farm' during WWII a few miles from my house (well before I was born, but we learned about it in a local history class. They used the silk in gun sights, as well as in scientific instruments. Pretty much anything that needs fine crosshairs could use it and did, as far back as the 1800's. Here's a little bit about it. The farm in Fredericktown, Ohio that is described about halfway through is the one I was referring to. It does sound as though it was a difficult job though, I agree.

Harvestmen, sometimes called daddy-longlegs, while not spiders, are omnivorous. Also, my daughter and I caught several spiders last fall and kept them in a terrarium for a couple of months. We fed them crickets by dropping in a dozen at a time. Because we wanted the crickets to stay alive until eaten, we also put a slice of fruit in every few days, and there was a little cup of water as well. The spiders happily ate the fruit (apples, peaches, bananas) while crickets literally climbed over top of them.

I've always been surprised that there were no vegetarian spiders. They've been around for forever; there's certainly been plenty of time for some of them to have evolved into a vegetarian group.

 

[EHocking]

...I've always been surprised that there were no vegetarian spiders. They've been around for forever; there's certainly been plenty of time for some of them to have evolved into a vegetarian group.

I'm not entirely unsurprised with this either and can even conjecture steps in the spider's evolution.

This particular acacia tree evolved a symbiotic relationship with an ant species that drives off other organisms.
The tree produces specialized nubs called Beltian bodies at their leaf tips for the ants to consume.
Spiders need fluids or they die from dehydration.
Spiders use this acacia tree for a source of hydration.
Spiders develop a behaviour for extracting hydration from plant buds by adaptation, both of habit and jaws.
Spiders that are too slow, get killed by the ants.
A jumping spider is fast enough to evade the ants.

That spider evolves to be Bagheera kiplingi

The above could of course be a "just so story", but that's quite fitting considering the spider's name!

ETA: Here's a 2008 paper on observations of the spider.
Exploitation of the Pseudomyrmex-Acacia mutualism by a predominantly vegetarian jumping spider (Bagheera kiplingi)

ETA, ETA: How cool is this?!

...The spiders also seem to build their webs in less attractive plant "real estate" and to actively defend their nests against ant invaders. Finally, Meehan added, the spiders might actually mimic the ants. Young spiders in particular look a lot like and seem to act like ants, one reason they have perhaps flown under scientists' radar for so long despite intensive study of the ants and acacias. Meehan suspects that the spiders wear the ants' chemical scent as well, a notion he is now investigating in more detail.

The research will appear in the October 13 issue of Current Biology.

Link to article in Current Biology. Unfortunately you need a Science Direct account to view the full paper. Rats...

 

[Skeptic Ginger]

It doesn't seem that weird to me. ....

The only vege spider EVER and it doesn't seen weird to you?

Kool article.

 

[Skeptic Ginger]

If this species is a Jumping Spider, it probably won't produce a lot harvestable silk, as it does not spin trapping webs (although possibly cladding for its lair, if it does keep one).

ETA - duh. Being herbivorous, it wouldn't use a trapping web in any case

Hypothetically a spider could trap airborne seeds.

 

[William Parcher]

How does a spiders fangs adapt to eat fruit?

The fangs may be unmodified and the spider eats the acacia bud in the same way it would eat an insect. The fangs are thrust into the wall of the bud and venom is injected. The venom "digests" the interior of the bud, and then the spider sucks out the liquid. Spiders take in liquid, not solid matter. I think that's how it works with spiders.

 

[Floyt]

...
That spider evolves to be Bagheera kiplingi

The above could of course be a "just so story"
...

I see what you did there

 

[Rosinbio]

This is just to weird. How does something like this happen?

Although this quote:


Contradicts this one:

Which would mean the spider is an omnivore and not a vegetarian, it still is very weird to me. How does a spiders fangs adapt to eat fruit?

As a former Arachnologists, I have never heard of any Arachnid feeding on plant material. Therefore, even though I had long stopped following the scientific literature about this utterly fascinating group of animals, I am inclined to be very skeptical of rare reports about spiders seen feeding on plant-buds, or pieces of fruit.

I would, therefore, appreciate full details about the source of information about a species of jumping spiders that feeds mostly on flower-buds.

I would not, however, completely discount the possibility of cases where, either the human observer, or the spider, were fooled.

Newly molted insects are pearly white. It is, therefore, theoretically not utterly impossible that the spider was feeding on very tiny, newly-molted insects, that rested on a bud, and were so small, and colorless, that the observer missed seeing them.

It is also theoretically not utterly impossible that a piece of plant material became so heavily contaminated with odors from prey the spider had learned to eat, that the spider bit into the piece of plant, mistaking it for the insect.

 

[EHocking]

As a former Arachnologists, I have never heard of any Arachnid feeding on plant material. Therefore, even though I had long stopped following the scientific literature about this utterly fascinating group of animals, I am inclined to be very skeptical of rare reports about spiders seen feeding on plant-buds, or pieces of fruit.

While scepticism is good, this is argument from incredulity.

I would, therefore, appreciate full details about the source of information about a species of jumping spiders that feeds mostly on flower-buds.

I gave links to the original announcement by the researchers as well as the latest link to their latest paper published 2 days ago. See post 7.

I would not, however, completely discount the possibility of cases where, either the human observer, or the spider, were fooled.

Newly molted insects are pearly white. It is, therefore, theoretically not utterly impossible that the spider was feeding on very tiny, newly-molted insects, that rested on a bud, and were so small, and colorless, that the observer missed seeing them.

It is also theoretically not utterly impossible that a piece of plant material became so heavily contaminated with odors from prey the spider had learned to eat, that the spider bit into the piece of plant, mistaking it for the insect.

It's all very good to denigrate another researchers work, but at least have the decency to ready their studies and papers before leaping to ill-informed conclusions.

 

[ellindsey]

It's not hard to see how this evolved in this case.

The spider lives on a species of acacia plant which cultivates symbiotic ants for defense. The acacia plant produces buds which are rich in fat and protein for the ants, and provides hollow thorns for the ants to nest in. The ants in turn defend the acacia from herbivores. Apparently the spider in question started as a predator on ants, sneaking onto the acacia and ambushing ants to either eat the ant or steal ant larva being carried by a worker ant. As worker ants also carry acacia buds to storage, it's not hard to imagine a situation where a spider ambushed an ant and stole the bud being carried by that ant, mistaking it for a larvae, then decided to eat the bud anyway. From there it's a small step to directly harvesting and eating the buds itself.

 

[Rosinbio]

While scepticism is good, this is argument from incredulity.
I gave links to the original announcement by the researchers as well as the latest link to their latest paper published 2 days ago. See post 7.
It's all very good to denigrate another researchers work, but at least have the decency to ready their studies and papers before leaping to ill-informed conclusions.

You should have had the decency to avoid criticising me for wrongs I had never done.

I did exactly what any responsible scientist would have done under the circumstances, i.e. when confronted with new information that does not fit easily with all the information he had before,. I conjectured about the possibility of alternative explanations, and requested a fully detailed reference (to examine).

I have by now (even before noticing your links), encountered this spider on my own on an online report from National Geographic tat provided the reference to the publication in Current Biology, as well as a very convincing photo of the drab spider holding a bright orange-colored bud to its mouth. I am sure I could check the journal in the Public Library (although I'm not sure whether I shall bother to do so. However, I shall definitely read the 2008 article to which you provide a link.

Since you now raise yet another possibility (that the spider chews on the buds for liquid (water), and not for any nutrients), and another poster raises the possibility that (since the adult ants transport both ant-larvae, and buds), the spider could mistake a bud for an ant larva (on which it prays) bite into the bud (and perhaps also utilize the nutrients in the bud). Mistaking a bud for an ant-larva seems even more plausible, if the adult ants inadvertently cause a contamination of buds with larval odors.

In view of all that, I think we should all be wise enough to suspend further judgement, until we know more details!

 

[jasonpatterson]

Rosinbio, as we've seen in other threads (magnetism in non-human animals, for instance), providing evidence for something that you feel is false cannot persuade you. What would it take to make you believe that this is a vegetarian spider? Read the articles at least before speculating wildly about what mistakes you assume the researchers made.

 

[Steelmage]

This summer my 7yo caught a spider and put it in a covered aquarium. She fed it leaves and grass every day for a week, until she lost interest. She also made sure that it had fresh water to drink. It was still alive when I released it so this too must have been a vegetarian spider!

(Ok, sorry.... I expect that spiders can probably live for a week without feeding, or that there were bugs on the leaves)

Correct, spiders can go on without eating for days, and live.

Link: http://www.spiderzrule.com/spider1.htm

Digestive system. A digestive tube extends the length of the spider's body. In the cephalothorax, the tube is larger and forms a sucking stomach. When the stomach's powerful muscles contract, the size of the stomach increases. This causes a strong sucking action that pulls the food through the stomach into the intestine. Juices in the digestive tube break the liquid food into particles small enough to pass through the walls of the intestine into the blood. The food is then distributed to all parts of the body. Food is also pulled through the stomach into a fingerlike cavity called the caeca. Because spiders can store food in the caeca, they can go for long periods of time without eating.

Link: http://www.earthlife.net/chelicerata/s-ecology.html

The amount of space a spider needs to live in is small, especially for web building spiders, they can go a long time without food and expend little energy waiting fro their prey. Spiders that hunt out their prey obviously use more energy but even these can live for weeks without eating. This, and the small size of most spiders means their can be a great diversity of spiders in every habitat with different species occupying different niches only a few centimetres apart.

 

[EHocking]

You should have had the decency to avoid criticising me for wrongs I had never done.

I did exactly what any responsible scientist would have done under the circumstances, i.e. when confronted with new information that does not fit easily with all the information he had before,. I conjectured about the possibility of alternative explanations, and requested a fully detailed reference (to examine).

No you didn't, you admitted that,

...I had long stopped following the scientific literature about this utterly fascinating group of animals

and then proceeded to denigrate the researchers' aptitude. You did NOT acquaint yourself with the evidence first, as "any responsible scientist would have done", as evidenced by,

I am inclined to be very skeptical of rare reports about spiders seen feeding on plant-buds, or pieces of fruit.

. If you HAD acquainted yourself with the evidence, you would have seen that two research teams, had discovered this behaviour indepently of each other in 2001 and 2007. 8 years of observation does not constitute, "rare reports".

I have by now (even before noticing your links), encountered this spider on my own on an online report from National Geographic

Very independent of you considering the link to the NG article was the second word in the OP of this thread.

In view of all that, I think we should all be wise enough to suspend further judgement, until we know more details!

It would have saved a number of antagonistic posts in this thread if you had taken your own advice.

 

[Rosinbio]

No you didn't, you admitted that, and then proceeded to denigrate the researchers' aptitude. You did NOT acquaint yourself with the evidence first, as "any responsible scientist would have done", as evidenced by, . If you HAD acquainted yourself with the evidence, you would have seen that two research teams, had discovered this behaviour indepently of each other in 2001 and 2007. 8 years of observation does not constitute, "rare reports".
Very independent of you considering the link to the NG article was the second word in the OP of this thread.It would have saved a number of antagonistic posts in this thread if you had taken your own advice.

My advice was intended for you too, but there is no way I can oblige you to accept it.

Instead you chose to try me in a court of your own creation, whith you as a self-appointed judge & jury. In no way can you oblige me to defend myself before such a "court".

I shall only state here that I do not need your permission to apply my skepticism wherever I see fit to do so, and that this thread first opened on my computer without any reference that I could check right away.

 

[Rosinbio]

Rosinbio, as we've seen in other threads (magnetism in non-human animals, for instance), providing evidence for something that you feel is false cannot persuade you. What would it take to make you believe that this is a vegetarian spider? Read the articles at least before speculating wildly about what mistakes you assume the researchers made.

Contrary to you I assumed nothing. I only conjectured about various possibilities. Unfortunately you cannot tell the difference.