I've been thinking about memetic 'ecologies' - that is to say, the environments in which memes compete. These ecologies are largely undefined. Are memes competing in our minds? BETWEEN our minds? On top of other memes?
Regardless as to what, exactly, these ecologies are, one thing is sure: memes replicate themselves by garnering attention. They seek to garner attention in individuals, and the most successful ones also seek to have infected individuals garner attention FOR them with other individuals.
But that's the only way memes replicate: by gathering attention.
Now, think about the 'real world'. Sure, we have creatures that do nothing but suck on the ground to replicate. Plants, fungus. But we also have animals - predators which consume both plants and other animals. Insects and other such non-animal creatures are, of course, included here.
Why haven't we developed memes that do this? Although memes compete and cooperate in some astonishingly complex patterns, we don't seem to have any memes which actively CONSUME other memes, deconstructing them and incorporating them.
I can think of a lot of memes which COMBINE with another meme - for example, "fey changelings" and "science" combine to form "extraterrestrial abductions". But this isn't an ongoing predation. This is a single merge, from which point the combined meme is propagated as is.
A proper predator moves in and consumes other memes, remaining largely unchanged itself. It can ONLY propagate where there is a prey meme to consume, and in the process of propagation, it destroys - or, at least, very badly damages - the local prey meme population.
The only example I MIGHT be able to see is 'skepticism'. The action of continually annihilating pseudoscience and mysticism continually strengthens the meme of 'skepticism', such that it is more capable of destroying this sort of thing again later. But skepticism is notoriously hard to spread. People will outright deny it, which rather limits its ability to spread to new locations and consume these prey memes.
Perhaps a more insidious version exists, and I don't even realize it. I'm open to suggestions from any angle.