In Japanese, weevils are called zoumushi, which means “elephant insects,” because their heads are elongated into a beak or rostrum (with mandibles at the end). The species I found today had a relatively short rostrum. It had a very effective defence behavior – dropping from the leaf when disturbed. In the second picture below you can see it has flattened itself against the leaf and is hanging on with only the legs on one side, the other legs tucked in ready to drop. As soon as I moved closer, it released its hold, fell and disappeared somewhere in the undergrowth.
Weevil = shirokobu zoumushi = Episomus turritus