There is much to be said for indolence. Had I cut back the fishtail lawyer vine (Calamus caryotoides), I would have missed this jolly gathering of moths.
At first I thought that the large, brightly-coloured moth near the leaf base was a female and the others were smaller males lined up on the starting grid. But a search through CSIRO's Australian Moths Online makes me think that they belong to different species in the family Crambidae,. As far as I can tell, the entire group is made up of small- to mid-sized moths that are very similar in external appearance, so, were I wearing a cap, I'd doff it in admiration of the lepidopterists that have worked and continue to work on the systematics of this group.
The closest match for the larger one is Margarosticha euprepialis, and for the smaller ones, Tetrernia terminitis. Small and large are relative terms. The moth in the image below has a wingspan of 14 mm.
This group of moths lays eggs on submerged rocks and leaves. The caterpillars are wholly aquatic, spinning silk shelters or sticking together fragments of vegetation to protect themselves from predators. Adults emerge from their cocoons under water and make their way to the surface to dry, before flying off to begin their short but exciting existence on land.
BunyipCo has blogged on this group of moths and has photos of these and other species from Far North Queensland. You can see pictures of caterpillars and their shelters at the Murray - Darling Freshwater Research Centre's bug guide.
