So you're not after a yes/no answer then are you? You're after a detailed description of what we know to date. You're both simultaneously demanding detail, whilst also demanding a simplistic yes/no answer. Which is it?Thermoman wrote:If 'No' is your choice, is this based on field work? Have you, or some other trusted authority, actually counted animal bones around hook-spined cacti and compared the result with that around straight-spined plants? Were the results published?
My "No" is based on the fact that searching and complete lack of reference to any such thing brings up no evidence of any such study. I could have instead said "Yes" to also fit your binary criteria, but that would be based on even less evidence - I'd be responding in the affirmative to something for which there is no evidence of. I could say I don't know, but that both is and isn't an acceptable answer based on your contradictory posts about wanting a binary answer but also being happy with a don't know, but then not being happy with it because it's not binary but in that case you might as well just have a thread with zero replies or a lot of don't knows.
You seem to desperately want to be told yes, cacti are evolved as vicious predators, and there's lots of evidence everywhere, but you're not going to get that, because there isn't, and they most probably aren't. You want to be told that spines have evolved to catch creatures that die and provide nutrients, whilst seemingly being evasive of the idea that those spines most likely simply exist to protect the nutrients they're already effective at obtaining and storing from elsewhere.
If we look at other actual carnivorous plants, they have additional mechanisms to aid their predatory aspects - they have an inherent ability to break down and absorb nutrients from living things, which cacti do not, and they have a clear and succesful lure, which cacti do not. There are many documented lures to increase pollination however, on flowers that are exposed - i.e. Pilosocereus azureus with it's cabbage scented flowers that attract bats, but these flowers are big and extend out well beyond the spines, explicitly allowing pollinators to avoid the danger of the spines when pollinated.
It's not even really clear that Puya chilensis is genuinely predatory, the original source seems to be mostly local hearsay and folklore rather than any evidence of it being a widespread trait. Are the sorts of sheep it catches even native to where it grows in the first place as opposed to imported livestock or descendants of?