Interesting article at Scientific American about the nature of consciousness, using bees as an example:

Although these experiments do not tell us that bees are conscious, they caution us that we have no principled reason at this point to reject this assertion. Bees are highly adaptive and sophisticated creatures with a bit fewer than one million neurons, which are interconnected in ways that are beyond our current understanding, jammed into less than one cubic millimeter of brain tissue. The neural density in the bee’s brain is about 10 times higher than that in a mammalian ce­rebral cortex, which most of us take to be the pinnacle of evolu­tion on this planet. In humans, widespread loss of cerebral cortex, as in the vegetative patient Terri Schiavo, leads to an irreversible loss of con­scious­ness. That is not to say that a cerebral cortex is necessary for consciousness in creatures with a different evolutionary heritage.

Very interesting stuff.