Connor Fitzpatrick is the author of today’s write-up. Connor writes:
Some common names for this member of the Aristolochiaceae family include calico flower and dutchman’s pipe. The native distribution of Aristolochia elegans covers western and central South America. However, it is also listed as an invasive species throughout the Pacific (link contains more photographs; also note that Aristolochia littoralis is a synonym of the accepted Aristolochia elegans).
This species poses a high risk of becoming a serious pest in Australia (more information on risk assessments by Pacific Island Ecosystems at Risk), with particular impact on insect populations. Butterflies of the family Papilionidae, including Atrophaneura polydorus, lay their eggs on Aristolochiaceae. The caterpillars sequester the toxin and use it as defence from predation (via Wikipedia). No ill effects are caused to the larvae after ingesting native Australian species of the family Aristolochiaceae. However, an as-yet-unknown chemical poisons and kills caterpillars of Atrophaneura polydorus after they consume the leaves of Aristolochia elegans (via Crossley and Evans).