With over four hundred species of butterfly represented in Australia, it’s tempting to think that the whole continent offers a bonanza to the keen amateur lepidopterist. However, that figure is not what it seems.
The Aurelian loves maps. Especially maps of isopleths. As Greek scholars will know, these are lines of equal plenty, and on this map they indicate the numbers of species that occur in different regions of the country.
And it rapidly becomes apparent that the regions of Australia are not all equal when it comes to butterflies. The majority of species are found in the wet tropics, those areas of rainforest on the eastern side of the continent. Warm and humid, these are a butterfly paradise, with over three hundred resident species.
Moving inland towards the central deserts, the number drops off rapidly. Yes, there are a few, very few species that will tolerate the dry heat, such as the hopelessly widespread and indiscriminate Meadow Argus and more interestingly, the Desert Sand-skipper, Croitana aestiva – a small, inconspicuous insect that few have seen, and even fewer photographed.
And then, as one approaches the south-west corner of Western Australia, the numbers begin to pick up again. This is an area of native forests with a pleasant Mediterranean climate, and around fifty species of resident butterflies, a number of which are endemic to the region.
That figure of fifty means that the number of species is similar to that of resident species in the UK. And again similarly, there are around fifteen species that can be found by the casual observer in local parks or gardens.
And then, for the rest, it starts to get interesting. Among the endemics, the beautiful Western Jewel can still be found within the metropolitan boundary of the city of Perth if you know where to look.
By contrast, the Speckled Ochre will require a four hour road trip from Perth to one of the few coastal locations where it has been observed.
Even for a skipper, it’s a disappointingly dull and mothy butterfly.
The Arid Bronze Azure will require another four hour road trip, this time in the opposite direction. You will be looking for one small piece of remnant woodland, the only place it flies.
If you’re lucky and well-informed, you can combine the trip with an excursion to one of the half a dozen rocky outcrops in the wheatbelt where the Laterite Ochre flies.
More widespread is the Wedge Grass-skipper which rather unsportingly emerges after the first of the autumn rains, rather than in the springtime as do most of the others.
Unsporting, in that photographers from other states must now make multiple journeys to Western Australia to complete their “bag”.
And then perhaps, the ultimate anomaly – occasional and transient colonies of that universal migrant, the European Painted Lady, Vanessa cardui.
Distinguished from the ubiquitous Australian version V. kershawi by the absence of blue centres to the dark spots on the hindwing, these colonies seem to have been established by adventurous individuals taking an unauthorised route out of their African hibernaculum .
So yes, while the region boasts a mere fraction of the species available in the rainforests of Queensland and New South Wales, no one who seeks a comprehensive account of Australian butterflies can afford to ignore the south-west.