Jimbo Jambo

The visual part requires a bit more imagination. It's pretty clear that Pikmin can see - they have eyes after all - but it plays a more important and complicated role just "see food, attack food." Since they don't likely smell very much, I think Pikmin use their sight to identify other members of their species, but their visual acuity and processing power are likely limited by their size, so they need a fast and simple way of doing so, something that is unique to them; I believe the leaves serve this purpose. Evidence for this idea is the fact that Pikmin leaves glow when they are idle, a clear visual signal of ''something'' (possibly to call the attention of the pack should a Pikmin become lost or stranded). The color of a Pikmin's body also always contrasts that of its leaf, so it is easily recognizable (White Pikmin have pink flowers, not white, so there is still contrast. It is also because of this that I firmly believe there should never and will never be Green Pikmin, since its body would blend with its leaf, which ''must'' be green). If one accepts this idea, it's easy to imagine why a Pikmin might follow Olimar, whose shining antenna probably sparks the same visual cues they get from other Pikmin, but to a much larger degree. It also explains why Pikmin accept juvenile Bulbmin, which probably smell and look just like Bulborbs save for their recognizable leaves, as their own (the adults are just so absurdly huge that they probably don't register as anything but an enemy to Pikmin).