I tried hard to find an adult, but no luck. Our cucumber plant is rapidly losing vigour under the onslaught of a lot of larvae. The 2nd photo shows their impact on an old leaf. Having checked on the web, I think it is probably E. vigintioctopunctata, which is sadi to feed on Solanaceae (esp. potatoes), curcubits (as ours are) and some beans. Larvae are described as being yellow in the first instar, then developing these darker markings: https://nzacfactsheets.landcareresearch.co.nz/factsheet/InterestingInsects/Hadda-beetle---Epilachna-vigintioctopunctata.html
I didn't change it, Jackie. E. vigintioctopunctata seems a likely candidate and I think it would be fine to call it that. Some (perhaps all) of the ACT sightings have been identified (by others) as E. sumbana, but I can't tell them from vigintioctopunctata so I haven't ventured to challenge that ID. Kim.
OK, must have been me having a seniors moment, and just using the only name available on ALCW. So I've done a bit of a web search and it appears that E. vigintioctopunctata sumbana is a synonym for E. sumbana, and that it specialises on cucurbits, not Solanaceae which are the favoured food plants of E. vigintioctopunctata, so I'll add E. sumbana to ALCW's list and confirm it as that.
Just one bit of missing info - neither of the two books we have in which it is mentioned (whoops, should have looked there before posting it) nor any of the websites I checked told me whether it was native or introduced. I've put it in as cosmopolitan and a minor pest. Hope that's right. I see Hangay and Zborowski suggest picking the larvae off by hand as a control method. That'll keep me busy for a while! Or as it's the end of the cucumber season anyway, I could just let them have their fun.
There is a complete current synonymy on AFD at https://biodiversity.org.au/afd/taxa/Epilachna/complete. Hermes Escalona of CSIRO-ANIC is currently working on Epilachna and has told me some of the Australian species may be introduced.
Thanks Kim, had a look but didn't extract much sense from it, except that it looks like cosmopolitan and minor pest might be close enough. So if the holotype of E. cucurbitae was collected in NSW, that suggests it is native, but then maybe it has since been synonomised with E. sumbana, which is also known from at least Indonesia?
Unfortunately, finding a specimen at a particular locality (whether it becomes a type specimen or not) is no guarantee that the species is native to that locality. There are plenty of examples where introduced species are not recognised as such, and described as something new. The longhorn beetle Karadinia nubila was described in 1942 from central Qld as a new genus and species, but was later found to be Lagocheirus funestus, a Mexican species deliberately introduced earlier as a cactus biocontrol agent!