Wednesday, 24 June 2015

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...

BACK ON WEDNESDAY

2 comments:

Susan said...

Ahem...your first unidentified beetle is a bug (check the antennae). I'd guess Scutelleridae, a jewel bug nymph, so entirely appropriate for the purposes of this post.

The second is another Scarabaeidae chafer of some sort, munching on pollen.

Ian Fraser said...

Oops, thanks Susan, duly noted...