Aristolochia and the Cairns Birdwing Butterfly
Author: Ian Dyer, Townsville Branch
Published: Journal March 2022
Image above: Chewed Aristolochia stem Feature
I recently planted a number of Aristolochia acuminata in various places in my garden to see what conditions they would be successful in. Nearly all grew well in various levels of shade and I was surprised at how quickly they were discovered by birdwing butterflies. I was able to observe their laying habits and watch the caterpillars grow.
Young caterpillar
Cairns Birdwings are the largest of Australian butterflies having a wing span up to 200mm. The female flits around the vine for some time before laying eggs, normally on new growth. The minute specks develop into caterpillars the size of my little finger. They have rather large spines in which they store poison gained from the plant thereby protecting against predators. It has been observed that the caterpillars ringbark the stems to reduce water levels and increase concentration of nutrients (see photo).
I also noted the smaller vines were almost eaten to the ground, but subsequently bounced back. For the pupal stage they attach themselves to the vine or nearby shrub/tree. Males will hover over the pupae to mate as soon as the females emerge before their wings are dry, so the next generation is underway quickly.
Young Aristolochia acuminata vine heading skyward
Reprinted with permission from ‘The Native Gardener’ Townsville Branch’s newsletter, June 2021.