More than likely it be pine, as nearly all the wood for hives in Australia is plantation. Every beekeeper has a different method of painting and preserving. The traditional method is to paint or soak the timber in copper napthenate and then leave to cure for a month or two and then paint the outside only with water or oil based paint, its your choice. Don’t paint the edges top and bottom this will cause the hive boxes to stick together. The copper napthenate prevents wood rot which will eat away your boxes in only a few years. Otherwise you should get at least 20 years if you keep sealing the external parts and the bees will seal the internals. I was originally concerned about the napthenate, but after a couple of months the smell is gone and you could always paint with an undercoat on the inside if you want to seal it.