It's usually like that on imgflip. A couple of people made mantis memes that made the front page (like 2 or 3), and suddenly it became a thing to make a meme saying something along the lines of "every single mantis meme hits the front page" or "there are too many mantis memes."
The same thing happened about Raydog memes. There are have been far more memes recently by users talking about Raydog and/or their perception of his popularity and how he gets to the front page than there have been memes by Raydog.
People just repeat what they hear I guess. I don't know.
Maybe it's a good time for conservatives to step up our meme game! :)