you're going to tell me a cricket has a brain.

a cricket has an eye, but it doesn't really have a brain. the nervous system is actually really localized, so it's able to function independently when parts of the body get chopped off. one wonders if that's a first step to regeneration, or a mostly lost memory of it. but, what that means is that the neurons in the head of the insect, in addition to the optic neurons, are just the local cluster for functions in the head (like eating), and are not any different than the local clusters elsewhere in the body, that are for movement and reproduction.

a brain is supposed to be a centralized processing unit that oversees the control of the entire organism, and insects do not have that; they have an optic bundle that controls for functions in the head and a series of other bundles that control for other localized functions.

so, then, do they have six brains? it's a meaningless compound phrase, a contradiction in terms. i was taught that they have a ganglia that exists throughout their body, rather than multiple brains. but, we can call things what we want, i guess, so long as you realize that "six brains" is sort of an incoherent idea, and that what you're calling brains are very limited and segmented in the scope of their functions.

it's interesting to look at insects that have eyes, though, because it seems to suggest that brains may have evolved from eyes, rather than the other way around. further, who knows; in a few million years, maybe some insects with eyes may develop actual brains, as the optic nerve takes control of the ganglia system.