|St Andrews Cross Spider|
The Wildlife of Greater Brisbane, the field guide I use to find out about local animal species, doesn't know why these spiders make these stripes.
I wonder whether it is not a way to seem bigger. Normally the spider sits on its web with the arms of the cross extending its paired legs. Nor does this one have a very tidy web.
Friarbirds are a common predator, says the book, and since I do see these occasionally I suspect them the reason for the here today gone tomorrow flavour of St Andrews Cross spiders.