The process from egg to butterfly is weather dependent and also depends on the regional climate. It can take about four weeks in the peak of the summer in warmer climates. The egg takes 5 to 10 days, the larva/caterpillar and pupa/chrysalis each take about 10 to 14 days.
In winter, autumn and spring it takes a lot longer (if it happens at all – they continue to breed in Northland).
The process slows down in cool weather; in this way we can ‘use’ the climatic conditions to speed up or slow down the creation of a butterfly.
When the pupa is ready to hatch, the shell will be transparent and you can see the dark colours of the butterfly’s wings folded up inside. The transformation happens suddenly and if you turn away for a few minutes you will usually come back to find a butterfly.