What were Australian Cane Beetles before the British colonised?
I was looking up about the whole 'Australian Cane Toad' problem, when I noticed something; the beetles that were the catalyst of having cane toads brought over are described as being "native" to Australia.
So the obvious question I have; how can Australia have a native insect species that targets sugarcane, when sugarcane itself isn't native to Australia?
I know sugarcane is native to some of the nearby Oceanic islands, but from what I could find online, it never got to the Australian mainland until it was introduced by British Colonies around the late 1800's, yet it only took till 1900 for them to be considered a pest large enough to have a government funded body tasked to clear them out.
What were these beetles doing to live before 1850, and how did it only take them less then half a century to have their entire life-cycles based around a plant that didn't exist before?