i think Akane becomes more jelous of Shampoo since Shampoo usually will actively provoke it or if Shampoo feels likes she's getting her way she'll stick her tongue out or make a face that pretty much says "ha ha, I won." So Shampoo literally draws out reactions from Akane and many times she purposely provokes the jelousy.

I think at times though Akane feels more THREATENED by Ukyo because she is Ranma's childhood friend, so she sees Ukyo as having an actual relationship of some sort with Ranma, which makes her uneasy, and maybe even sad because she feels or is reminded that this was a part of Ranma's life that she didn't get to share with him or be apart of.

idk. I sometimes thinks that shampoo gets under her skin the most. But she's most jealous of Ukyo because she and ranma new each other as children, and I think Akane's jealous because it feels like a part of ranma's life that she wants to be, but wasn't apart of, and Ukyo was.

SHAMPOO IS ANNOYING

I think Akane is more jealous of Shampoo, but she sees Ukyo as a bigger threat.

Yeah I agree with BloodMoon1 because they were childhood friends, and also Ranma calls her his 'cute' fiancée.

Akane is the author's self-insert and Shampoo is the prettier girl.