Surviving by disguising

Baby German cockroaches of both sexes have been found to mimic the smell and feel of adult female cockroaches,the better to dupe adult males into spreading their wings and exposing the hidden pantries beneath—pools of beery maltose sugar,proteins and fats. Within-species mimicry is generally rare in nature,said Coby Schal,a professor of entomology at North Carolina State University,who recently reported with his colleagues in Animal Behaviour on the gambit they dubbed jail baiting.

Perhaps the most remarkable case of mimicry is of the mimic octopus of Indonesia,with so many shape-shifting,shade-changing tricks at its disposal even eight sleeves cannot hold them. A report published this month in the Biological Journal of the Linnean Society presents the evolutionary backstory to Thaumoctopus mimicus,a marine mollusk discovered and described only in the last dozen years. Like most octopuses,T. mimicus can use its nervous system to instantly change colours into a perfect wallpaper blend. Unlike most other octopuses,the mimic will sometimes choose to make itself more conspicuous to potential predators.If it must venture out to forage in dangerous open waters,it assumes a menacing disguise appropriate to context. For skating along the sea bottom,the octopus turns its skin bumpy and beige,compresses its body,pulls its limbs to its side: it’s a toxic flatfish,undulating its fins,staring you down with its top-sided eyes. “When it’s being pestered by a damselfish,it will turn one of its arms into a sea snake,with the contrasting banding pattern of a sea snake,and with the tip of the arm thickened to look like the snake’s head,” said Healy Hamilton,a biodiversity and informatics expert at the California Academy of Sciences and an author on the report.

We humans also like our mimicry in small,imperfect doses. Psychologists are coming to appreciate the profound importance of nonconscious mimicry in making us feel loved and appreciated,or simply smoothing the edges of our everyday affairs. Without realising it,when we’re conversing with friends,we match our tone of voice and speech rhythms to theirs,adopt similar body posture and even imitate their tics. Studies have shown that,when students are instructed to work cooperatively with somebody who engages in either repeated hair touching or foot shaking,the students soon start fiddling with their hair or waggling a foot. Waiters who repeat their customers’ orders word for word,or mimic a customer’s body language,earn higher tips than waiters who paraphrase the order or forgo the gestural mirroring.