How come the caterpillar does not die by eating poisonous vine?
P. praevenosa is not a particularly poisonous vine – there are about 14 + described aristolochic acids and this one is quite low in toxicity for vertebrates. Second, in the 25 million years or so it has taken for butterfly and plant to co-evolve, the larvae have developed specific enzymes that break down the toxins and use them for food – except for Dutchmans Pipe where the 2 did NOT co-evolve in Australia! This is a common situation in “old” Australian insects, many of which have only one, or a few food plants, and where their guts have evolved over very log periods of time, and to be immune to otherwise toxic plant compounds. Think of the Wanderer – it has the ability to break down the toxic milkweeds!
