This is a Wanderer Butterfly egg about a week after it was laid. I’ve done some Googling and the information I found said the eggs hatch in 3 – 5 days. There are no signs of any caterpillars on the bush but there have been small ants. I’m not sure if the ants would eat the eggs but I’ve put some Vaseline around the base to discourage them.
I’ve marked the leaf this egg is on so I can check it over the next week.