Apple songs on Niconico

Hello, can someone tell me what's up with those apple songs on Niconico? They are very prominent in the Weekly Vocaloid Ranking right now. haha

Edit: So they are sung by Neutrino AI Tohoku Kiritan and Yukkuri, too. They are parodies/covers of anime and Vocaloid songs.

So apparently there is a girl from Idolm@ster who is known with apples. (Tsujino Akari?)