Some Notes on cannibalism in Theraphosid Praelarvae and Larvae

[Theraphosid Research Team]

It is well known that tarantulas are cannibalistic in most cases. The nymphs of the 1st moulting stage are often separated very soon, since they often start to decimate each other very quickly. For a long time it was thought that the praelarvae and larvae would feed exclusively on the yolk supply of their very voluminous abdomen and the spiders would only be able to take in their own food from the nymph stage. The opposite is the case, because the following picture and the show that this cannibalism can start much earlier. The picture shows 2 praelarvae parasitizing on an egg together. In the video you can see a larvae that has slammed its chelicerae deep into the abdomen of another larva and is now starting to suckle it. Obviously, tarantulas can eat long before the 1st nymphal stage.



View attachment YouCut_20220302_134150940.mp4

 

[Wolfram1]

Wow i was not aware it could start so soon. I was aware that the Larval stages in Spiders were often much more cannibalistic than the actual first nympth stages, but that praelarvae were already capable of canibalism is stunning. May i ask if you are proposing this for all species? And with which species were the observations made?


Here is a recent observation me and a friend made:

He hatched an M. balfouri sack.
100 eggs, 92 fertile, no apparent cannibslism during the praelarval and first 2 larval stages. Once they reached L3 cannibalism started. 3-4 L3 would consume another Larvae togeter. They did not seem to prefer the still less developed L2 or freshly molted L3 but rather grabbed what was closest. around 3 L2 seemed to have died of natural causes in this period, these were ignored. Food, from live Fruitflies, dead Firebrats, dead mealworms, dead roaches of different species, dead crickets, all cut up to offer easy access were similarly ignored. Cannibalismus by L3 continued but stopped once they reached the first nympth stage. A few N1 fell victim to some of the last L3. In the later days some of the remaining L3 as well as all of the N1 started to accept prekilled prey.

Cannibalism seems to have stopped once they reached N1. Around 52-53 Nympths are remaining.

 

[Theraphosid Research Team]

This phenomenon can obviously be observed in numerous species such as Avicularia, Xenesthis, Chromatopelma or even Ornithoctonus aureotibialis, as the attached photo shows. So far, however, no "conditions" are known according to which the parasitic Praelarvae proceed.

 

[8 legged]

I have read several times that there is a suspicion that the focus is usually limited to "weak, sickly" animals. But that seems more like: what is currently offered is being eaten up... I will keep a better eye on the brood in the future and start counting earlier. Thanks for the information!

 

[viper69]

This is interesting. Few things about nature surprise me, and while I didn't think this happened, I'm not surprised. Thank you very much for this post.

 

[cold blood]

It is well known that tarantulas are cannibalistic in most cases. The nymphs of the 1st moulting stage are often separated very soon, since they often start to decimate each other very quickly. For a long time it was thought that the praelarvae and larvae would feed exclusively on the yolk supply of their very voluminous abdomen and the spiders would only be able to take in their own food from the nymph stage. The opposite is the case, because the following picture and the show that this cannibalism can start much earlier. The picture shows 2 praelarvae parasitizing on an egg together. In the video you can see a larvae that has slammed its chelicerae deep into the abdomen of another larva and is now starting to suckle it. Obviously, tarantulas can eat long before the 1st nymphal stage.

Nice pics.

Twice I have observed this...honestly when I saw it I was confused and not really sure if I was seeing things right as I also thought they were incapable of eating at this stage.....glad to have my observations confirmed.