Caterpillar an expert in mimicry

By Bec Crew | April 17, 2014

This little caterpillar has elaborate mimicry to appear much bigger and scarier than it is.

Contributor

Bec Crew

Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.

HELLO NIGHTMARE MATERIAL. Behold, the fantastically creepy caterpillar of the pink underwing moth (Phyllodes imperials).

Native to the undisturbed subtropical rainforests of northeast Queensland and northern New South Wales, the species is also found in parts of Papua New Guinea, the Solomon Islands, Vanuatu and New Caledonia.

Proud owner of the toothiest fake grimace in town, the P. imperials caterpillar exemplifies an insect camouflage strategy known as ‘mimesis’. Mimesis describes the ability of an animal to adequately mimic certain natural objects in its environment to make it appear less edible than it actually is.

Whether that’s a toxic species of insect or a larger, more formidable creature such as an owl or snake, or perhaps just plant parts such as thorns, leaves or flowers, this strategy involves using elaborate patterns, colours and shapes to produce a convincing disguise.

Caterpillar mimics teeth

Many species of butterflies and moths sport large eyespots on their wings to emulate the face of a larger animal, but the P. imperials caterpillar has taken this defense strategy one step further by adding rows of terrible teeth to the mix.

This skull-like pattern sits on the P. imperials caterpillar’s back, and when it’s threatened, it will rear up its upper body segments and curl its head down towards its ‘chest area’, to create the illusion of a much larger head. The caterpillar will then stretch out the skin covering its fake head to reveal the eyespots and teeth patterns that sometimes lie hidden under a roll of flesh.

Now, I know what you’re thinking, but fear not, because P. imperials caterpillars do not feed on the souls of old people and disobedient children. They subsist entirely on milk or carronia vines (Pycnarrhena australiana and Carronia multisepala), which also provide a place for them to breed.

Once the P. imperials caterpillar has gone through the process of metamorphosis, it will emerge from its cacoon as a bronze-coloured moth with large forewings shaped like autumn leaves and distinctive pink patches on its hindwings. Its wingspan will stretch up to 170 mm long.