Bone Collector Caterpillars and Fake Flower Spiders: Discover 7 Animal Illusionists

Plenty of animals employ optical trickery to stay safe or secure meals, but these creatures are masters of illusion. Let's (try to) take a look at...

• The Stunning Sea Sapphire
• The Cunning Flower Crab Spider
• The Sinister Bone Collector Caterpillar
• The Devious Decoy Spider
• The Camouflage-Curating Decorator Crab
• The Tricky Tawny Frogmouth
• The Masterful Mimic Octopus

The Stunning Sea Sapphire

Did you know that there's a crustacean that can flash brilliant blue... or turn invisible?

The sea sapphires are copepods (a tiny type of crustacean) that live in the world's oceans. Their bodies are translucent, leaving them pretty much invisible to the human eye... but the males can flash brilliant bursts of blue, red, gold or green, something thought to help them attract a mate. To an observer, a group of them can make the ocean seem studded with sparkling gems - hence the name "sea sapphire."

The secret to a copepod's display can be found in guanine crystal plates on his back. These crystals are held between layers of cytoplasm and reflect certain wavelengths of light - with the color depending on the species.

This reflection only functions when light hits the copepod at the right angle... so if the sea sapphire moves, the reflection stops and the creature fades from sight!

The Cunning Flower Crab Spider

Spiders have a knack for being sneaky, but the flower crab spider is a real piece of work.

So first off, why is it called a flower crab spider? Well, these arachnids have two long pairs of front legs that they tend to keep spread out like a crab's pincers - and they can also scuttle sideways. Rather than building a web, they sit on flowers and wait for an unwitting insect to come to them.

Females are able to gradually change color (the males don't seem to have this talent) to blend in with flowers, adopting a white, pink or yellow pattern that mimics their chosen bloom. If the spider can't find a suitable perch, it can simply grasp on to a stem and spread itself out... with the end result resembling a small flower.

The disguise certainly seems effective - the spiders catch bees, flies and pretty much any insect that visits their flower, often leaving a pile of husks on the ground beneath. There's another benefit to this disguise - birds and other predators will often miss the ambushing arachnids!

Researchers have also observed another species of crab spider performing cooperative camouflage. The spiders were seen perched on a hoya plant from the rainforest in Xishuangbanna, China, where a male and female seemed to be working together to mimic a flower. The pale body of the female matched the petals of a hoya bloom, while the smaller and dark male sat on her back and resembled the pistils and stamens of a genuine hoya. Not a fun flower for a fly to visit!

The Sinister Bone Collector Caterpillar

It may be something of a surprise that there are carnivorous caterpillars out there. Even stranger is the bone collector, a moth caterpillar that lives alongside spiders and dresses like a serial killer.

The bone collector lives in the dark crevasses and hollow trees of Hawai'i, hiding near the webs of arachnids. The caterpillars "borrow" the hard work of the spider, snatching dead or captured insects from the web to eat.

Naturally, the spiders would object to the freeloading caterpillar if they knew it was there. The cunning creature gets around any neighborhood disputes by building a silk bag to live in... and decorating it with left-over body parts. Wings, bits of weevil, earwig and even molted spider chitin can be added to the bag, with the caterpillar resembling a pile of inedible cast-offs to the unwitting spider!

The Devious Decoy Spider

Disguises can help keep a creature alive, but there's always the risk that a predator will still try its luck. Some Cyclosa spiders from Peru have come up with a safer solution - they build decoy spiders from silk and leftovers!

The replicas are surprisingly convincing at first glance, and are much larger than the real spider. Potential predators could easily be put off by the massive spider waiting for them, while the small Cyclosa hides in comparative safety. If a bird or wasp does decide to attack, all they'll get is a useless pile of silk and rubbish, while the real arachnid scuttles to safety!

The Camouflage-Curating Decorator Crab

Do you like gardening? So do the decorator crabs, crustaceans that cover themselves in plants, sponges, algae, anemones and even bryozoans (simple aquatic invertebrate animals.)

The crab isn't doing this just to look pretty, of course. The living coating acts as an incredibly realistic camouflage - and some of the components can even sting fish that get too close.

Crabs molt as they grow, which obviously results in losing this coat. The decorator is a practical gardener though and transfers its collection to the new shell, attaching the animals and plants to small, Velcro-like bristles (called setae) on its shell!

The Tricky Tawny Frogmouth

The tawny frogmouth is a strange looking bird from Australia and Tasmania. It looks a bit like an owl with an extremely wide mouth (hence frogmouth) but it's actually a relative of the nightjar.

The tawny frogmouth is nocturnal, so it sleeps on tree branches throughout the day. Obviously this leaves the bird rather vulnerable to predators - or it would, if they could find it. The feathers of the frogmouth are a mottled mixture of gray and brown, allowing it to blend in incredibly well with tree bark. The bird also hunkers down and flattens itself against the branches - the end result resembles nothing more than a bit of broken branch.

The Masterful Mimic Octopus

Most of these cunning creatures have only a single trick (albeit a good one) to disguise themselves... but the aptly named mimic octopus has a whole cast of characters on standby to keep itself safe.

Like most octopuses, the mimic can change color to match its surroundings. It can also contort itself to further change its outline. Here's where things get weird - the canny cephalopod can use a combination of color changes, contortions and nearby terrain to mimic other animals.

The repertoire of the octopus includes poisonous flatfish (it curls its tentacles around itself to make a flatfish body) lionfish (sticking out brown and cream striped tentacles like venomous spikes) and even deadly sea-snakes (using black and white tentacles to form a long "body.") It can even enhance the sea-snake impersonation by tucking its body into a hole and keeping the tentacles sticking out!

Thanks for reading - perhaps you'd also like...

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Sources and Further Info:

• Beautiful sea sapphire can make itself invisible in an instant
• Flower crab spider
• Male and female crab spiders “cooperate” to mimic a flower
• Bizarre "bone collector" caterpillar discovered by UH scientists
• Cyclosa Menge, 1866 (Araneidae) Orb-Weavers Build Stabilimenta That Resemble Larger Spiders
• These Spiders Build Decoy Dummies of Themselves | National Geographic
• Decorator crab
• Tawny Frogmouth
• Mimic Octopus
• Mimic Octopus: Master of Disguise