I'd seen this mud wasp nest on the back verandah for a while - entry open. Then one afternoon, while daisying, I saw something odd - something small struggling along dragging a spider. It was a wasp, black, making for a daisy bush - with some difficulty as the spider was twice its size. The wasp climbed up about 20cm - strong wind-gusts not helping its cause - and wedged the spider in a branchlet fork - then flew off. So I grabbed my camera.
The wasp returned - checked that all was well with its prey - and flew off again.
I waited for a while, but nothing. Returning 20 minutes later I saw that the wasp had repositioned the spider.
There was no further action, but the next time I went back the spider was gone and, on the way back inside, I saw that the mud nest had been sealed.
The folks at SAM think it is a Potter Wasp, although I have yet to find an image of one with black and white striped abdomen. There are several species of wasp commonly referred to as Mud-daubers... anyhow, if you know, please let me know. Several of these wasps specialise in spiders (Spider Wasps) - first they paralyse the spider, then drag it to their nest (sometimes they'll bite the legs off to make it easier to move)where eggs are laid on it. The eggs hatch and the larvae feed on the still-living spider, avoiding vital organs to avoid killing it too soon. As adults they will feed mainly on nectar.