How does evolution explain butterflies?

Question

I've been wondering about butterflies lately. Evolutionarily speaking, I understand that mutations cause different forms which may be more suitable for adaption. Some variations are more successful than others and those genes that caused the advantage can be passed on to the next generation. This is how different finches have differently shaped beaks and giraffes are somehow related to horses.
But with butterflies, I don't know how such a rapid change in form could evolutionarily arise. A baby chimp, fish, hippo, etc. looks like a miniature version of an adult of the species. But butterflies and moths go through a chysalis stage at the middle of their lifecycle which involves a specially specific constructed enviroment to develop into a completely different form (unlike tadpoles). How could genes for not one but two forms (catapillar and winged butterfly) be passed on? How does evolution explain this?
I give a very warm and kind thanks to the entomologist, lepidopterist or evolutionary biologist who answers this.

Answer 1

don's answer is pretty much spot on.

Most of the 'higher' groups of insects go through this process of metamorphosis, with different life stages as larva, pupa and adult.

As an evolutionary strategy, this adaptation means that the larvae and adults can occupy completely different ecological niches, and do not compete with each other. The larvae are essentially eating machines, adapted for obtaining as much nutrition as possible in the shortest amount of time. Because of the metamorphosis in the pupal stage, they do not have to waste metabolic energy on reproductive structures, or wings and flight muscles.

The adults are reproducing and dispersal machines. Because the larvae of these insects have gathered so much nutrition, many adult insects do not even have to feed (some don't have functional mouthparts - saving more metabolic energy). They can concentrate all of their resources towards mating and getting eggs laid.

The insect groups that undergo complete metamorphosis like this are some of the most successful and diverse organisms on the planet, so the evolutionary advantage of this adaptation is fairly evident. It includes not just the butterflies, but beetles, flies, wasps, ants, and a few other groups like fleas.

How this complete metamorphosis adaptation evolved was through modifications of the incomplete metamorphosis seen in 'lower' insects like dragonflies, true bugs and termites.

Those insects have larvae that are essentially very much like the adults, only without wings. When the insects are born, they go through several moults before becoming adults. The stage between each moult is known as an instar. During each instar, the wings and reproductive organs are slowly developing, and are fully developed only the final instar, the adult stage. In the complete metamorphosis insects, they have simply added an instar which is devoted solely to metamorphosis, where the entire body chemistry is rearranged.

Later selective pressures have shaped the forms of the larvae and adults in different ways. Because these completely metamorphosing insects can take advantage of completely different environments at different times, and natural selection can work to develop completely and totally divergent forms in the larvae and adults of these insects.

The earliest completely metamorphosing insects would still have had larvae and adults that were pretty similar (this is still seen in some beetles that don't change too terribly much between life stages). The rapid generation time of most insects (some can go through multiple generations in a single year) means that evolutionary selection can act rather rapidly on insects (compared to say, mammals), and has resulted in the wide variety of insect species we see today.

Answer 2

Many animals go through a larval stage, not just butterflies. Most insects do. So do crustaceans. And molluscs. And amphibians. And even those which do not go through a larval stage as such still undergo a sort of metamorphosis from the embryonic form to the mature form. The morphological difference between a human embryo and a newborn human baby is certainly as great as that between a tadpole and a frog, or between a caterpillar and a butterfly. I don't see it as a unique situation at all.

Answer 3

There are few examples of butterfly fossils, but the oldest ones we have are around 40 million years old and look very much like butterflies do today. ...no missing link here. Not all evolution moves in long slow processes; sometimes a major catastrophic event or some other phenomenon can lead to rapid change in adaptation. It could be that butterflies responded to something which happened rather suddenly in their immediate environment. As far as I know, the details of this are still unsolved.

Answer 4

I think you're confusing Evolution with Metamorphosis. Catapillars don't evolve into butterflies and moths... they metamorphosise into butterflies and moths. It's part of the lifecycle of the incect. It's just like most other insects begin life as a grub and grow up into a beetle, or maggots to flies.

Answer 5

The caterpillar that is most adapted for survival (camouflaged or bad tasting to birds) has the best chance to mate. Like wise the adult butterfly that is the most adapted or camouflaged has the best chance of surviving to matie and passing on its genes. So there are 2 stages that the btrfly has to survive through and adapt. But that is common in many animals. The young fawn that is camouflaged best etc.

Answer 6

Butterflies as Bioindicators

Answer 7

Well I am no scientist at all, but wanted to tell you your question is very intelligent and engaging. I hope you get an answer! Now I want to know! Good luck

Answer 8

one tiny change at a time, over millions of yrs, thats how evolution works