2011 has been a great year for Yellow Admiral butterflies in Cottesloe.
In May 2009, with help from Robert Powell, I sewed seed of a local annual – Native Pellitory (Parietaria debilis) at Cottesloe Native Garden, under the dappled shade of local tea trees, beside the sand path. A small number of plants have grown each year but this year we have a large patch of healthy plants, many are 40cm tall.
The flowers are tiny and the plant is not showy but it is the native plant food for the Yellow Admiral Butterfly (Vanessa itea) – it is the plant on which Admiral butterflies lay their eggs. The Yellow Admiral finds the plants by the chemical smell emitted from the plants. Admirals are strong fliers and they will travel long distances to find their preferred breeding plants.
The Yellow Admiral is a medium sized butterfly with dark colouring which ranges from orange brown to reddish brown – with a large pale yellow oval shaped patch on the forewings. When females are laying their eggs on the Pellitory they often flutter quite slowly from plant to plant. Now I can see the evidence that butterflies have visited these plants, as many leaves are folded over to make tiny shelters for the growing caterpillars. The tiny larvae make these leaf shelters to protect themselves from birds.The larvae (caterpillars) take about 4 weeks to grow to full size – about 3cm long. They then find somewhere to pupate. The pupation stage lasts about 10 to 18 days. The day before the butterfly emerges the pupae will change colour and you can see the dark wings tightly furled up inside the pupae. The butterfly usually emerges from its chrysalis on a sunny morning and sometimes you can see them stretching and drying their wings in the sun before they fly off for the first time – then the cycle of life and metamorphosis begins again.