It's a (mini) beast on a blossom! 😊
I couldn't find a common name for the jewel beetle (Castiarina pallidiventris), but, if you're interested in etymology, the 'pallidiventris' in the scientific name means pale underside (you can't see it in my image, but it's a light yellow). I also couldn't find much general information about this particular species, other than that it's widely distributed across southern Australia, from SW WA east into SA, VIC & over the border into southern NSW.
I've mentioned in a previous post that beetles (order Coleoptera) are the most diverse group of animals on earth - there are ~400,000 species globally! And jewel beetles (family Buprestidae) are one of the biggest groups of beetles - there are ~15,000 known species at the moment, with ~ 1,200 of these in Australia. While most feed on nectar or leaves as adults, the larvae are wood borers. They pupate inside the wood of the host plant, and the adults bore their way to the outside after metamorphosis. They don't live long as adults - some species only live for a day or two, while the longer-lived ones last for ~2 weeks (they make the most of it though - it really is all about food & sex!). .
The flower this beetle was feeding on belongs to a Beaufortia - I think it's a purple Beaufortia (Beaufortia purpurea), which is endemic to a small area near Perth. If I've IDed it right, it's listed as Priority 3 flora because it's only known from a few locations but isn't under imminent threat, & flowers from mid-spring into summer. There are 21 other species in the genus Beaufortia, & they're all endemic to south west WA.