What is her object when, before proceeding to sink her hole, she inspects her acorn, from above, below, before and behind, with such meticulous care?
She is making sure that the acorn is not already occupied.

The larder is amply stored, but it does not contain enough for two.

Never in fact, have I found two larvae in the same acorn.

One only, always only one, digests the copious meal and converts it into a greenish dust before leaving it and descending to the ground.

Only an insignificant shell remains uneaten.