An Unhealthy Obsession.
I removed the extra male as gently as possible, and then put the mating pair (stripy male and female) in another box to give them a little peace. At once the rest calmed down. That pheromone is a powerful molecule, but it seems that once the source is removed the effect soon fades away.
I then managed, at last, to separate yesterday's happily mating couple (stripy female-unstripy male), removed the male, and after waiting a few seconds replaced the paper under the female - which was now dirty. She then promptly started to lay her eggs. It were as if I had given her permission.
I am trying to leave the silk moths alone now, and divert my mind back to the Patagonia novel. I want to try and finish the Tehuelche edits this week because I have to give in the revised manuscript to my editor at Seren in March.