Most sensitive solar cell

 It was sunset tonight: you can see the Belt of Venus on the horizon. The chef solar-powered kinetic toy was still going but the ladybird and a third toy had long since stopped.

I would say that the ladybird's panel is angled more towards the light. Maybe it is not to do with the amount of light coming in but to do with the mechanics of the mechanism. Need to think of a way to test that!