If there exist ants within the spawn radius belonging to more than one distinct bot then the food is destroyed and disappears from the game.
Since the combat phase is before the gather phase, is it even possible for this to occur, given the gather radius is smaller than the combat radius? One-on-one, the ants would kill each other before they get a chance to gather the food, so the only possibility I can imagine is if some complicated combat resolution managed to leave two ants standing with the food piece right between them. I haven't given it much thought, but I somehow doubt it's possible...