Any honeydew not eaten by ants rains down from trees infested with aphids, and is plausibly thought to be the origin of ‘manna’ in the Book of Exodus. It should not be surprising that ants gather it up, for the same reason as the followers of Moses did. But some ants have gone further and corralled aphids, giving them protection in exchange for being allowed to ‘milk’ the aphids, tickling their rear ends to make them secrete honeydew which the ant eats directly from the aphid’s anus.
