So last week found several workers running around the top of the tank, OMG!!!! Put them back in just to find some more a few moments later and again and again..There was a tiny hole in the mould at the base which they had chewed through. Phew no one got stung thank god….
Their tube is now busting at the seems with larvae and pupae, they are desperately in need of something bigger. I can’t decide whether to go with the moat idea as nothing i have tried seems to stop them climbing the sides. Such a worry.