# Metallic insects: What, Why And How?



## NYbirdEater (Aug 11, 2004)

I sometimes see flies around my area (NorthEast) that look metallic green, gold and even blue. Then recently for the first time, I saw what appeared to be a bee, but instead of the normal black and yellow stripes, it had green metallic stripes with yellow stripes. Looked exactly like the ordinary bees around my house accept for the color. 

Why do some insects look metallic, that is what's the benefit? 

How chemically do their body's produce the colors is it on their exoskeleton or hairs or something else?

What's with the metallic bees?


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## Horrido (Aug 22, 2004)

> Why do some insects look metallic, that is what's the benefit?


Intraspecies indentification or communication, as well as camouflage in shiny vegetation, or to confuse or warn predators, as a conspicuous insect may indicate it's toxic or has a nasty sting or bite, or a flashing insect may make it difficult to focus on and track its target in pursuit (like trying to pursue somebody in a strobe light, your eyes can't process and plot the course of the image).




> How chemically do their body's produce the colors is it on their exoskeleton or hairs or something else?


Three ways immediately come to mind, which may create the colors singly or in concert.  The most common cause of metallic colors relate to the structure of the insect's shell, which is made of a substance called chitin.  Because chitin is actually transparent, small cracks and fissures in the shell, scales, or hairs refract the light like a prism, creating the typical metallic blues and greens you see.  In some cases, there is actually a colored pigment in the shell that creates/aids the the color shading, and the source of the pigment is often related to the foods they eat.  For a few insects, a powdery substance is produced that they then apply to their bodies.




> What's with the metallic bees?


I don't know, they tend to be very solitary, but whether it's being shy or snobby, they still refuse to talk to me about it.    

(But since they readily sting if disturbed, and very bright green, I think their coloration is of the structural variety for intraspecies identification and to tell predators to leave them alone.  Family Halictidae is the most common metallic bee.)


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## NYbirdEater (Aug 22, 2004)

cool, thanks for the info


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