Spider Hunting Wasp question

[Geoff F]

About a week ago - back in the summer! Close to those S. Devon woods.

I saw what I think is Anoplius nigerrimus tending her burrows. There were 2 burrows close together. She was frantically rushing around (making focusing difficult) and dragging some dead plant material which was stuffed into a hole. This continued until eventually the burrow entrance was covered with earth.

Then she moved to the second burrow where it all happened again. First of all she dragged a piece of dead twig over the entrance, no mean feat for such a small creature, but then had a change of mind and removed it. When satisfied with the dead leaf/moss stuffing this hole was also covered with earth.

Eventually she ran off into some nearby grass.





I didn't see any spiders being taken into the burrows which left me wondering, were the 2 burrows already provisioned with spiders. In which case why didn't she block up the first hole before catching the second spider. Which would make sense to me.

Or were these a couple of 'empty appartments' which had been constructed in advance and the entrances hidden to prevent another insect using them in the meantime. I know that some species construct burrows before catching their prey but do they hide the entrances.

Perhaps if there are a lot of easy targets they catch 2 quickly in a row, like a fox in a chicken run, then quickly dig 2 burrows.

Any suggestions about this behaviour?