Sorry dont have a link but was talking to a friend and I was informed (And this is just rumor) that while Megatron is hiding in the Jungles of Africa, he somehow aquiers a new power-type mode. Could it be the "Heart of Darkness" form/mode that was hinted at a while back? Only time will tell. But I was also told that this mode may allow him to have a dark power that allows him to siphon Energon from other Transformers.
(Kind of reminds me of the last Prime cartoon with the orb harvister Starscream had.)