The tribe adjacent to Mono Lake regularly gathered and consumed some sort of fly that regularly hatched out in rather significant quantities - offhand, the details escape me. There are several other groups as well that regularly consume bugs.

There is no biological reason why insects cannot be consumed by humans. For us Westerners, particularly, there is only a culturally determined "ick" factor.

Somewhere back in my college days, I heard the statement that there is no known group which makes 100% effective use of the biologically useful potential foods available to it - culturally determined taboos always come into play.

Chocolate covered ants, anyone?