Kids love to imitate the behaviour of adults. It is an important way of learning as they grow up. Entertainers earn laughter by mocking and exaggerating the features of others. In nature, imitation is not about learning or fun, but is a matter of life and death. Creatures have to protect themselves as well as foraging for food. Imitation is the way of survival of many animals; it is known scientifically as “mimicry”.
Sheep in Wolf’s Clothing -- Defensive Mimicry
Pretending to be a fierce animal can increase the chance of survival by evading predators. Aggressive wasps are popular models, as most insects avoid them. The wasp moth is particularly good at mimicking wasps with its yellow and black body and transparent wings!
Snakes are also often imitated. Some caterpillars of Sphingidae moths and Papilio butterflies have eye spots on their bodies to mimic snakes’ eyes. When threatened, a Papilio caterpillar even sticks out an osmeterium, a red forked fleshy organ that closely resembles a snake’s tongue!
Also among butterflies, Danaids are poisonous, deterring predators. Numerous non-toxic butterflies, including Common Mime (Chilasa clytia) and Danaid Egg-fly (Hypolimnas misippus), as well as several moth species, have evolved to imitate the Danaids.
The great master of defensive mimicry is a spider, the Ant-mimicking Jumper. The species not only exhibits behaviour of aggressive Weaver Ants, but also frequents the vicinity of Weaver Ant colonies for protection. But how can the eight-legged spider pretend to be a six-legged ant? The answer is that it sways the pair of front legs to mimic the ant’s antennae. Some larger Weaver Ants sometimes carry a smaller ant in their mandibles while walking. The larger male Ant-Mimicking Jumpers even mimic this paired-up walking motion!
Master Killers Playing Dumb – Aggressive Mimicry
Similar to Ant-mimicking Jumper, Ant-like Sac Spider (Castianeira hongkong) is also an expert in mimicry. However, this time the protagonist is trying to conceal its identity as a predator to increase the chance of a successful hunt. This is called aggressive mimicry. Preying on the ants of Polyrhachis spp., Ant-like Sac Spider, with its close resemblance to the ants, can easily get into the ant colony without alerting the ants.
A classic example of aggressive mimicry involves false cleanerfish resembling cleanerfish. Bluestreak Cleaner Wrasse (Labroides dimidiatus) feeds on the parasites and dead skin of other fish, earning it the nickname “cleanerfish”. Sabre-toothed Blenny (Aspidontus taeniatus), on the other hand, is a fake version that mimics cleanerfish and gets close to other fishes not to clean them but to take large bites off them!
Turning Invisible -- Plant/Inanimate Mimicry
Some animals imitate plants or inanimate objects to conceal themselves in the environment. Most of this behaviour (such as stick insects) comes from the need to evade their predators. For others, however, this is a way to disguise themselves when hunting. For example, Crab Spider (Thomisus labefactus) has a white or yellowish white body to allow it to hide among flowers, waiting to prey on small insects that come for nectar.
Text | Candy Yau