Desert Beetle

This tiny little green bug is the only thing capable of withstanding scorching heat and freezing nights in the deserts of this world, where no one else seem to be capable of surviving. This beetle not only survives there seemingly with no problems, but it lives and seems to prosper.
Because of its perseverance it has appeared in many cultures of the world as a symbol of resilience and life, even at places where everything seems to be against prosperity. It is also a sign of last hope, while there are some places that see it in a negative sense - as a bad omen of incoming disasters, mostly famine.
On a first glance there is nothing special, really, about these creatures - they just got lucky in the genetic pool. Their outer shell is able to regulate heat so their squishy little insides don't get burnt or frozen; they are able to survive on very little substinence (they are scavengers and eat basically whatever they can find in the desert, as anything that ends up there has very little chances of surviving giving the beetles big chances for good dinner every time and when times get particularly tough, they can either fly away outside of the reach of a predator or dig themselves deep underground to hybernate for months, sometimes even years, until things get better.
What is particularly interesting about this bug is its pigmentation. When their little bodies get ground up, they are the only source of the Tai jade dye, a very vibrant green shade that doesn't fade under the sun and creates for a lasting and non toxic colour for fabrics and other materials.
Which is why fake oasis are being planted and experimented upon in various deserts in the world, particularly in the Tai kingdoms, to attract these creatures in bigger numbers despite the fact that the oasis cannot survive in the desert on its own, and is there only to provide a green beacon to these little insects to feast upon. And then be squished for fashion.