Blue Beasts of Happiness #3; anything but feathers!

For the last two postings (starting here) I've introduced some blue birds (including one bluebird) which I hope brought you some happiness in these challenging times. Well they brought some to me, so in the absence of any suggestions to the contrary I'm going to assume that it's worth concluding this bluey series with a post on other animal groups and other blue parts of birds apart from feathers. Like 'blue' feathers virtually of these other blue animals achieve their blueness not by blue pigments, but by some very clever physical properties at the nanoparticle level. (And no I don't really understand the intricacies of it either, but there's plenty more information on that out in webland.) The essence however is that layers of cells (or tiny bubbles in the feathers) are arranged precisely so that blue light only is reflected, and often reinforced to make the effect even stronger. 

However I'm going to start today with a couple of very special examples indeed of blue animals. As I've stressed, there are no known blue pigments in any birds, or in almost any other animals either. But not quite...  Here are two animals from very different groups which, shockingly after all I've said, do have blue chemicals to colour themselves.

Blue Triangle Graphium sarpedo Currarong, south coast New South Wales.
This is one of a very small handful of butterflies worldwide which contains the pigment pterobilin;
a very few others contain blue phorcabilins and sarpedobilins, but that's about it.
All other blue butterflies - and we'll meet some below - just play with physics and our eyes.

Bluebottle, or Portuguese Man o' War, Physalia physalis, beached on the south coast
of New South Wales. They drift on the ocean surface, their float at the mercy of
the winds and currents. Here the mercy gave out and this one died on the beach. Its stinging
tentacles must still be avoided at all costs though! However you're seeing it now
because, like some other marine organisms, it too has genuine blue pigment, in this case
complex combinations of carotenoids (common plant-derived pigments which
many birds, for instance, appropriate to produce red and yellow feathers) with proteins.

And these pale blue crabs may or may not fit this category; some crabs do have blue pigments, and these Soldier Crabs could well do so too.

 

Soldier Crabs Mictyris longicarpus, south coast New South Wales.

For the rest however we're back to familiar theme of cleverly reflected light. We started with a butterfly so let's meet some others; there are many blue (or part-blue) butterflies and moths to choose from, all of which use precisely aligned two-layered scales which together reflect and reinforce blue light.

 

Maybe I could have shown fewer butterflies, but you can't really have too many, can you? And I'm sorry that I can't identify all of them - as ever any help will be appreciated.

 

Blue Pansy Junonia oenone Peyeria, Madagascar.

Unidentified nocturnal moth drawn to the lights of the Tambopata Research Centre,
southern Peruvian Amazonia.

Sucking water from the sand by the Rio Madre de Dios, southern Peru.

At Amazonia Lodge, Manu Biosphere Area, southern Peru.

At Huembo Lodge, north-eastern Andes, Peru.

Brilliant Blue Junonia rhadama Lac Alarobia, Tananarive, Madagascar.

 Blue-banded Eggfly Hypolimnas alimena Cairns Botanic Gardens.

Shining Oak-blue Arhopala micale Cairns Botanic Gardens.

Rajah Brooke Birdwing Trogonoptera brookiana Mount Kinabalu NP, Sabah,
Malaysian Borneo. This magnificent creature is even more spectacular than
it looks from this angle.

Satin-green Forester Pollanisus viridipulverulenta Yeldulknie CP, Eyre Peninsula,
South Australia. This iridescent beauty can be blue or green, depending on the angle.
And iridescence is a topic I'll come back to one day.

Unidentified night moth that came to the lights of Owlet Lodge,
north-eastern Peruvian Andes. I think this one's extraordinary.

Turquoise Emperor Doxocopa laurentia Iguaçu Falls, Brazil.

Blue Tiger Tirumala hamata Bundjalung NP, north coast NSW.

Staying with insects, butterflies and moths aren't the only ones with blue wings, though others (including some dragonflies) tend more towards flashes of blue iridescence, rather than permanent blue.

Carpenter Bee Xlyocopa sp. Gomantong Caves, Sabah, Malaysian Borneo.

This dragonfly however, west of Sepilok in Sabah, seems to have solid scales on part of the wings.

In the case of blue in insect bodies, the mechanism seems mostly to involve particles suspended in a waxy layer within the cuticle, above a melanin-darkened background, to reflect and intensify blue light. I have no reason to suppose that any of the blues of the insects that follow don't derive this way, but I don't suppose many of them have been specifically studied either.

Blue Ant Diamma bicolor Orroral Valley, Namadgi National Park, near Canberra.
Despite the name this is a spectacular wingless wasp (which apparently has a
formidable sting). From the shine, this might be a case of iridescence too.

Mountain Grasshopper Acripeza reticulata, Namadgi National Park.
If disturbed she raises her wing covers to expose the dramatic blue and red abdomen;
she wasn't sufficiently worried about me however.

Unidentified grasshopper (by me anyway), Peyeris, Madagascar.

Blue Ringtails (damselflies) Austrolestes annulosus Canberra.

 

 

 

 

Grasshopper, Mt Kupé, Cameroon. I like the blue side bar; I also thought
it was fairly likely you've not seen this one, given where it was.

 

 

Tropical Rockmaster Diphlebia euphoeoides, north Queensland.

Frog skin colours are very complex, with often three layers of different cells in the skin. In the case of blues, iridophores sit above melanin-filled melanophores and reflect blue light back.

Ecuadorian Poison Dart Frog Ameerega bilinguis, Sacha Lodge, Amazonian Ecuador.
Fortunately I'm not likely to be putting anyone at risk by attempting to emulate this local guide, who
seems to have developed a resitance to the potentially lethal toxins carried by the frog.
You're not likely to encounter the frog without such a guide to warn you off.

Reptile scales can have similar structures.

Skink, Manglares Churute NP, Ecuador.
Presumably the blue tail is to attract attention of predators, who are
then left with the tail, but no skink. It's one of the most beautiful
skinks I've ever seen.

In lizards, especially dragons (agamids) where males display with bright colours in mating season, the blues can often be switched on and off by contracting the melanin cells below the light-scattering layers.

 

Kenyan Rock Agama Agama lionotusm, Tarangire NP, Tanzania.

Blue-headed Tree Agama Acanthocercus atricollis, Queen Elizabeth NP Uganda.

Australian Water Dragon Intellagama lesueurii, National Botanic Gardens, Canberra.
The large population of these impressive lizards, quite habituated to people, is
a feature of these magnificent gardens.

And I can find no information on how a creature produces a blue tongue, but I imagine the layer priniciple applies here too.

Eastern Blue-tongued Lizard Tiliqua scincoides, Kakadu NP, Northern Territory.
The bluetongue group comprises the world's largest skinks; the blue tongue is part
of a threat display which, unfortunately for them, relies entirely on bluff.

There are very few examples of true blue in mammals. Among them the face and buttocks of male Mandrills are well-known (though other colours complement them), as are the testicle of Vervet Monkeys Chlorocebus pygerythrus. Sorry to lower the tone, though they are very striking...

Male Vervet Monkey, Serengeti NP, Tanzania. This common ground-feeding
monkey is found throughout east Africa from the Horn to the bottom of South Africa.

Blue skin in mammals follows a now-familiar theme, though the structure comprises an array of collagen fibres over a melanin layer.

Which brings us back to birds, in which bare blue skin is not as uncommon as you might reasonably imagine. Here the collagen fibre layers also are the basis of it, though it must have evolved quite separately from the same system in mammals. A perhaps surprising number of birds display an attractive ring of bare skin around the eye. Here is a selection from a wide array of families (meaning they developed it independently of each other, as well as of mammals) and three continents.

Blue-faced Honeyeater Entomyzon cyanotis preening, Griffith, NSW.

Channel-billed Toucan Ramphastos vitellinus Chapada dos Guimarães, Brazil.

Yellow-throated Toucan Ramphastos ambiguus Wild Sumaco Lodge, north-eastern Andes, Ecuador

Chabet Vanga Leptopterus chabert Itafy, Madagascar.

Hoatzin Opisthocomus hoazin, Manu Bioshere Reserve, Peruvian Amazonia.
This is truly one of the most extraordinary birds in the world, which has had
no close relatives for at least 64 million years - about the time the non-bird
dinosaurs unwillingly left the stage.

Little Corella Cacatua sanguinea, Mutawintji NP, western NSW.

Madagascan Paradise Flycatcher Terpsiphone mutata Ankarana NP, Madagascar.

A few bird species have actual blue eyes, whose blueness is (like mine) due to particles suspended in fluid.

Crested Orependola Psarocolius decumanus Sacha Lodge, Ecuador.
These magnificent birds are large tropical members of the North American
blackbird family.

Blue bills, feet and extensive area of skin are all due to the layered collagen structure, and can be quite dramatic.

Blue-billed Duck Oxyura australis, Canberra. Only the males have this impressive adornment.
    

Dusky Woodswallow Artamus cyanopterus, Canberra.
This blue bill is not such a striking feature, but worth looking for.

Double-barred Finches Stizoptera bichenovii, Darwin.
Another bird which doesn't flaunt its little blue bill, but it's an attractive accoutrement.

Blue-footed Booby Sula nebouxii, Puerto Ayoras, Galápagos.
Surely one of the most admired bird appendages in the world; they really are amazingly blue.

 

But I'm going to end with an Australian bird, the mighty Southern Cassowary Casuarius casuarius. Only a tropical bird, and a large one (which doesn't lose as much heat as a smaller one) could afford to dispense with all of its head and neck feathers in order to flaunt a truly dramatic colour display.

Southern Cassowary, Mount Hypipamee National Park, north Queensland.
It's not easy to get a clear photo in its rainforest home but I think this
does justice to its featherless finery.

Well that will do us for blue creatures for a while. I hope it's give you something to smile at, and perhaps ponder over. Keep your eyes out for nature's wonderful blues.

Previous post in this series here.

NEXT POSTING THURSDAY 18 MARCH.
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