Do intellect devourers need to eat to survive? If so, do they eat brains?
I know I can easily houserule either way as DM, I'm just curious if there's any official data about it.
I'm playing 5e, but I'm open to lore from other editions.
Possibly the most iconic Intellect Devourer to appear in 1E is the one that stalks players aboard the crashed starship in Expedition to the Barrier Peaks. This particular individual has been trapped on the ship for "many years" (p.19), or "decades" (pp. 3, 19). It was one of many types of alien fauna originally trapped in "stasis cages", but was one of the first ones freed, even before the crash. After it was freed, "The intellect devourer [has] freed other creatures from stasis in order to eat them..." (p.11) but it is currently is trapped in a part of the ship without food.
Unfortunately, the module does not tell us whether they need to eat (but suggests it may have been quite some time since it has), or suggest how they eat (1e illustrations do not show them with mouths and they do not get a bite attack). But thanks to the quote above, we at least know that they can and do eat.