Do Tarantulas use there venom for all prey?

[deathfingers66]

I'm sure when a Tarantula tackles larger prey like rodents, snakes lizards, etc. it uses its venom, and that the fangs alone must quicken the death of the prey, but what about a larger spider feeding on a roach or big cricket, does it save its venom depending on prey size?

 

[clearlysaid]

I'm going to have to say tarantulas do not use their venom on all prey. I say this because from what I've read tarantulas expend a lot of energy to make their venom so they only use it when absolutely needed... and also, I've seen my G rosea take over 15 minutes to kill a B dubia juvie. I would assume if she injected venom in it, it would have stopped squirming pretty quickly... but it didn't.

 

[Fingolfin]

I've seen B. dubia still kicking their legs despite being half consumed hours later... I'm going to go with no. The other thing is, I've seen B. dubia struggle with pokies especially, either they aren't using their venom or that particular roach might have some resistance to it. Its an interesting thought!

 

[JDeRosa]

It's my understanding that their venom is actually their digestive juices as they have no internal digestive system. Then they suck the already digested insides out of the cricket/roach/etc.

Hey, I am new here. How do I start a new thread in the classifieds section? This forum isn't that user friendly.

 

[Tuwin]

I would think they do as that's how they liquify the inside of prey so they can consume it, am i wrong?

 

[RottweilExpress]

I would think they do as that's how they liquify the inside of prey so they can consume it, am i wrong?

Yes you are wrong.

Tarantulas has cheliceral teeth. Further regarding the mouthpart and macaration:

"Spiders are split into two major feeding groups based on the method they use for prey manipulation. The feeding method of any particular species is based, perhaps erroneously, on the presence or absence of cheliceral teeth. Cheliceral teeth are sharp, hardened points in a line on the chelicerae above the fangs. The fangs fold in on top of the teeth, facilitating a firm, crushing grip on the prey. In most, but not all spider species having cheliceral teeth (including tarantulas), the prey is ripped to pieces and manipulated into an unrecognizable ball, or bolus. In spiders with no cheliceral teeth, although also included are certain species with cheliceral teeth, the body of the prey is perforated in one or more areas by the fangs. The prey is not torn apart, and if an exoskeleton is present, it looks much like it did in life after feeding is over. Traditionally, arachnologists have used the presence of cheliceral teeth as the indicator of what method a spider species will use when feeding on prey, yet accept that some with cheliceral teeth are exceptions. Cheliceral teeth may be a good indicator of feeding methods, or they may not. Many cobweb weavers (Theridiidae) have few or no cheliceral teeth, such as the largest members of the family, the widow spiders (Latrodectus). Even without cheliceral teeth, widow spiders are capable of tearing the prey to pieces, but they don’t. I suggest some other adaptation, such as a more powerful sucking stomach, or specialized mouthparts, may be of equal value in explaining why some species tear the prey apart and others do not. This hypothesis needs scientific evaluation, but so does the cheliceral teeth hypothesis."

Regarding venom and/or digestive enzymes:

"All spiders, except the hackled orbweavers (Uloboridae) and certain species of the primitive segmented trapdoor spiders (Liphistiidae), have venom. It seems logical to many that spider venom should contain not only toxins to incapacitate the prey but, conveniently, also all the digestive enzymes needed to break down the tissues. This is not the case. The venom of many spiders studied does contain a connective tissue enzyme, which does make sense, since loosening the connected organs seems like a valuable adaptation. However, spider venom has none of the required enzymes needed to break down proteins, carbohydrates, fatty acids or other materials. Spider venom plays an insignificant role in digestion."

Further information:

"We know that spiders regurgitate all required enzymes from the mouth and onto the prey (in those that tear up the prey) or into the prey (for the rest). With tarantulas and others that shred the prey, these enzymes are poured onto the prey bolus, then “licked” back into the foregut. The widow spiders and many crab spiders force enzymes into the hole they made in the prey, then suck it back into the mouth. They repeat this action who knows how many times before completing the meal."

Source (I don't know the credibility of this study):
Spider Digestion & Food Storage
Robert Gale Breene III
College of the Southwest, Carlsbad, New Mexico USA

 

[dtknow]

Interesting. I've seen two general ways of killing prey in T's.

Many terrestrials will grab the prey, and start immediately crushing it up. I'd guess no venom is used here.

I've seen my pokies and psalmos when dealing with large prey grab the prey(lobster roach) on the backside and hold onto it. The roach stops moving after maybe 10 minutes at which time the T begins chewing. Venom might play a part here.

 

[Tuwin]

Interesting...

I knew about cheliceral teeth but i didn't know that the venom was an insignificant role in digestion

 

[saminthemiddle]

Interesting. I've seen two general ways of killing prey in T's.

Many terrestrials will grab the prey, and start immediately crushing it up. I'd guess no venom is used here.

I've seen my pokies and psalmos when dealing with large prey grab the prey(lobster roach) on the backside and hold onto it. The roach stops moving after maybe 10 minutes at which time the T begins chewing. Venom might play a part here.

I have seen another method too that obviously involves venom. Although I haven't seen it with tarantulas (yet) I have seen true spiders hit and run a prey item. They very quickly (it only takes a split second) pounce, strike, and retreat from their prey. Once the venom starts kicking in the spider comes back to finish the job. I have only seen this done by very small spiders tackling prey bigger than themselves.

 

[deathfingers66]

I have seen another method too that obviously involves venom. Although I haven't seen it with tarantulas (yet) I have seen true spiders hit and run a prey item. They very quickly (it only takes a split second) pounce, strike, and retreat from their prey. Once the venom starts kicking in the spider comes back to finish the job. I have only seen this done by very small spiders tackling prey bigger than themselves.

My 2.5 inch Ceratogyrus brachycephalus will often kill the prey bring to burrow, then come out quickly ready for another cricket or roach(its venom seem strong to where it kills its prey fast allowing it to do this.).Its cool to watch so I hope it continues this way of eating when it gets bigger, but i doubt it.