What did they eat before?

At the moment my citrus plants are lunch for a range of caterpillars. Early in the season the Dainty Swallowtail (Papilio anactus) laid eggs on a Kaffir Lime (Citrus hystrix), that resulted in a batch of caterpillars (pictured left). This week caterpillars of both the Orchard Swallowtail (Papilio aegeus), pictured below, and the Dainty Swallowtail are happily munching on the new Lemon (Citrus x limon) leaves. Given that both species of butterfly are endemic to Australia it begs the question ‘What did the caterpillars feed on before lemons and limes were introduced into Australia’?

Lemons and limes are from the plant family Rutaceae, commonly called citrus. Lemons and limes originated in India and southeast Asia but it turns out that there are many species of Rutaceae that are native to Australia. The majority of plants of the genus Boronia, Correa, Eriostemon, Zieria and Philotheca (to name but a few) are Australian and are all of the Rutaceae family, citrus!

I bought the Kaffir Lime to specifically attract Dainty Swallowtail butterflies. It is positioned next to a native garden full of Correas and Boronias. I should have saved my money. Who knew!