Iridescence Without Feathers

This is the third and final in this series of iridescence in animals; the first two dealt with birds, but this time I want to look at other animals - mostly invertebrates but with a fish and a lizard thrown in. The principles are exactly the same as in feathers, with layers of cells underlain with melanin reflecting light from bottom and top surfaces such that they reinforce or cancel each other, giving gleaming colours like polished metal or glass. 

Beetle carapaces seem particularly suitable for the task - or maybe it's just that there are so many beetles!

This scarab beetle, from along the Tamar River in Tasmania, has to be one of the most
beautiful animals I have ever seen; the glowing colours were spectacular.

Christmas Beetle (because they emerge in huge numbers to eat eucalyptus leaves in high summer),
Anoplognathus sp., Canberra. These are also scarabs.

Scarab on Acacia flowers, Leeuwin Naturaliste NP, south-west Western Australia.

Diphucephala sp. on Acacia dealbata, Tinderry NP, south-east of Canberra.

Wasp, Standley Chasm, central Australia.

Fly, Batang Ai NP, Sarawak.
It's OK, I'd given up on the tea by now anyway!

Unidentified bug - ie Hempiteran - Sceales Bay, western South Australia.
(My thanks to Susan - below - for correcting my previous blunder with this one!)

The iridescence need not be in the body though - many insects have iridescent wings, and butterflies of course feature heavily in the iridescent hit parade.

Pollanisus viridipulverulenta Yeldulknie CP, western South Australia.
Only a small moth, but it absolutely gleams.

One of the brightest lights in the Bornean rainforest, the blue flashing against the black background.
This, in Kinabalu NP in Sabah, is the Rajah Brooke Birdwing Trogonoptera brookiana, I feel sure, though that is usually described as having 'electric green' flashes on the wings.
It actually looks more like T. trojana, but that is endemic to the Philippines.

Butterflies and moths are not the only ones with iridescent wings however.

Scarlet Percher Diplacodes haematodes Standley Chasm, central Australia.

Carpenter Bee, Playa Espumilla, Santiago, Galápagos.
Not much iridescence here, but a few seconds later that changed with a change of position
- see below!

 

Finally, a couple of vertebrates, as promised. Some frogs have the characteristic, but I don't have photos of those. Many fish feature brilliantly flashing silver as they turn, perhaps to help confuse predators.

Barramundi Lates calcarifer, Territory Wildlife Park, south of Darwin.
Most Australians probably regard Barramundi as 'ours', but in fact it is a species found from northern
Australia through south-east Asia all the way to the Middle East.
(Annoyingly I didn't notice the reflection of the Emergency Exit sign at the time!)

Finally, one of the most handsome lizards I know.

This big lizard, in all his breeding finery, is a male Eastern Water Dragon Intellagama (formerly Physignathus) lesueuriiAustralian National Botanic Gardens, Canberra.

I hope this little series has given you some pleasure too. Perhaps something slightly less flashy next time...

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Humming with Iridescence

Last time I revelled (as I hope you did) in some birds that flaunt iridescent colours - colours that flash with light, and even change with the angle of viewing. I won't repeat the details of how it works here, but now I want to dedicate this entire post to just one family of birds, the fabulous hummingbirds, a South American group which has spread into North America in relatively recent times. Hummers seem to specialise in iridescence, with rich layers of cells that reinforce reflected and refracted light to magnificent effect.

It's probably a cheek for someone from this side of the Pacific (and with a non-spectacular camera) to be featuring hummers, but I am such a fan that I can't help myself. Hopefully some of these will give you pleasure too. I think these little gems can speak for themselves throughout this post for the most part.

Amethyst-throated Sunangel Heliangelus amethysticollis, Inca Track near Machu Picchu, Peru.

Andean Emerald Agyrtria franciae, Alandbi Lodge north-west of Quito, Ecuador.
Common in the northern Andes, but always exquisite.

Blue-mantled Thornbill Chalcostigma stanleyi, El Cajas NP, southern Ecuador.
A mostly high-altitude bird which shines all over!

Buff-tailed Coronet Boissonneaua flavescens, Bellavista Lodge, north-west of Quito.
A relatively unassuming hummer - until it catches the light.

White-necked Jacobin Florisuga mellivora male, Alanbi Lodge, north-west of Quito.

Collared Inca Coeligena torquata female, Bellavista Lodge, north-west Ecuador cloud forests.

Golden-tailed Sapphire Chrysuronia oenone, Wild Sumaco Lodge, north-eastern Andes, Ecuador.
Some of these birds really have big names to live up to, but they seem to manage with ease...

Green Violetear Colibri thalassinus near Cusco, Peruvian Andes.
A widespread beauty.

Green-crowned Brilliant Heliodoxa jacula, Mirador Rio Blanco, north-west of Quito, Ecuador.
A relatively big hummer, and brilliant indeed.

Green-crowned Woodnymph Thalurania colombica, Alanbi Lodge.
Surely one of the most stunning in the glittering constellation of hummers.

Long-tailed Sylph Aglaiocercus kingii, San Isidro Lodge, Ecuador (above)
and Violet-tailed Sylph A. coelestis, Sachatamia Lodge, north-west of Quito.
This stunning species pair evolved on opposite sides of the Andes, east and west respectively, from a common ancestor; this phenomenon is one reason that the northern Andean countries
are so fabulously rich in natural diversity.

Purple-bibbed Whitetip Urosticte benjamini, Alanbir Lodge, is limited to the northern Andes.

Rufous-tailed Hummingbird Amazilia tzacatl, also at Alanbi.
A very common hummingbird from Mexico to southern Ecuador, but who could ever tire of them?

Velvet-purple Coronet Boissonneaua jardini, Sachatamia Lodge, north-west of Quito, above and below.
This is one of the most iridescent of all hummers - a big claim, and not really borne out by these photos
taken on a dull wet day. But compare the wing edges and thighs in the two photos to see how the iridescence
'switches on and off'.

 

Violet-bellied Hummingbird Juliamyia julie, Umbrellabird Lodge, southern Ecuador.
There is no bad way to end a posting on either iridescence or hummers
and I reckon this bird emphasises that. Wow!

Thanks for staying with me through a fairly self-indulgent post and one without a lot of extra information - this cast doesn't need help though.

Next time I'll finish this mini-series by looking at iridescence in other animals, mostly invertebrates.

BACK ON WEDNESDAY 24 JUNE (WHEN I'LL BE BACK AT MY DESK!)