Orchard Swallowtail Butterfly (Papilio species): Although the gardens at Yallaroo are on an exposed hill, we have been able to grow citrus in sheltered situations. At present (June 2001) we have lemons and mandarins ripening. During spring and summer the citrus plants are home to large caterpillars. They are about 4 centimetres long, green with blue spots. The image shows a mature caterpillar. When disturbed a fleshy Y-shaped organ appears from behind the head. This organ, known as osmeterium, emits a pungent citrus smell. This is probably a defence mechanism against bird attack.
The caterpillars develop into large butterflies with black and white colouring. They are the largest butterflies that we see cruising around Yallaroo.
The Orchard Swallowtail feeds on members of the Rutaceae plant family. The range of this beautiful butterfly has increased dramatically since the introduction of exotic citrus plants. Their diet before European settlement consisted of native members of the Rutaceae family particularly species growing in rainforest. With the introduction of citrus, both in orchards and home gardens, the butterflies have become established in areas previously not suitable as butterfly habitat. The caterpillars cause little damage to citrus plants. Allow the caterpillars to survive and your domestic environment will be enriched by the presence of these beautiful butterflies.