Blue Moths

[mothman27]

It seems to me surprising that there are so few blue moths. There seems to be a similar phenomenon with green butterflies although there are some exceptions like Papilionidae and lycaenidae but here in Indiana I have not collected a single green butterfly. Anyway, I have yet to hear of a single blue saturniidae although there are orange, yellow, green, red, pink, brown and many other colors. Are there any blue or purple saturniidae? I can only think of a handful of any kind of moths that have much blue such as Catocala fraxini, Ctenucha sp. and several day flying moths. It there an explanation for this?


Tim

[exoticimports]

My guess is that blue holds no value at night.

[jshuey]

Sept 19, 2018 3:20:20 GMT -8 exoticimports said:

My guess is that blue holds no value at night.

Plus there are no blue pigments (that I am aware of). All blue color is refracted light - which is in short supply after dark.

[Paul K]

Well, blue colour is a pretty bad camouflage during day so all blue moths if there were any millions of years ago are all extinct being eaten.
Day flying moths that are blue are usually toxic and no one wants to make a meal of those.

[Paul K]

Sept 19, 2018 5:13:59 GMT -8 jshuey said:

Sept 19, 2018 3:20:20 GMT -8 exoticimports said:

My guess is that blue holds no value at night.

Plus there are no blue pigments (that I am aware of). All blue color is refracted light - which is in short supply after dark.

You are right. The scales are empty and the light rays are refracted and the blue rays are visible.
There are actually no colours at all when none of the light is present.
We can only see things when light hits the object and the colour pigment absorbs one of the light rays or mix of them and rest of the rays are bounced back.

The whole universe existence is much more complicated as most of us think. No observers, no existence and so on...

Paul

[nomihoudai]

Paul, I am confused by your last sentence. A color has anyway always been a perception and not an object on its own. Therefore, it doesn't make sense to deduce laws on existence (that deals with objects, and not perceptions) from colors.

Furthermore, each one of us is in every moment observing the whole universe. Because of things like that a single magnetic monopole (not discovered yet) in the universe would already be sufficient to describe all of electromagnetism.

In any case, with a PhD in physics I couldn't leave a sentence like 'no observer, no existence' uncommented.

[nomihoudai]

Answering the topic, I don't know why there shouldn't be blue pigments?? Tetrapyrroles and some Caretenoids can be blue. They are present in Lepidoptera.

But as already said, being blue doesn't make sense when you want to hide during the day light. There is some blue moths in the genus Milionia, there is Catocala fraxini, and there is a wealth of blue microlepidoptera. In Saturniidae it wouldn't make much sense to be blue as they hide during the day because they fly so slowly.

[Deleted]

Do you mean entirely blue or with partial blue? Even in our impoverished UK we have moths with some blue on them.

[jhyatt]

Nomihoudai,

Does your comment about carotenoids and porphyrins mean that I'm not the only natural-products organic chemist on the forum? Small world...
J. Hyatt

[nomihoudai]

Not exactly John, I have a PhD in biophysics and in our group some people also worked on energy transfers in organic molecules (OLEDs). This is the closest I ever came to the topic, I myself focused more on thermodynamics