Field Lines in Expanding Space Explained

[Feeble Wonk]

Can anyone explain to an ignorant layperson, with as little mathematics/geometry as possible, whether field lines in expanding space become "farther apart". I view this question as being closely related to the concept of quantum foam distribution in expanding space... do virtual point particles in quantum foam form farther apart in expanding space?

 

[Feeble Wonk]

OK... I've apparently not phrased my question in the appropriate fashion. Let me try again.
If we imagine "empty space" a evenly distributed with its quantum foam of bubbling virtual particles, and then recognize that the involved expanse of space will expand or contract subject to factors such as a gravitational field, how does the corresponding distribution of the virtual point particles change?