Why do caterpillars metamorphose?

[motorollin]

I can understand that caterpillars might have an evolutionary pressure to grow wings in order to evade predators or find food and mates. But normally when survival of the fittest is in play, the unfit members (in this case those without wings) will not survive or find food/mates. Either way, their genes will not be progressed. I would expect this to lead either to an extinction of the caterpillar species in favour of the butterfly/moth species, or a separation of the two in to separate species. So what is the advantage of the eggs hatching as caterpillars and then changing in to butterflies/moths? Why would this a metamorphic behaviour be evolved rather than an evolution to a different species?

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moto

[motorollin]

A4000_Mad wrote:
They get jealous when they see birds up in the sky :-D

:roll:

A4000_Mad wrote:
But it is incredible how a skin full of pus can turn into legs and wings and start flying  8-)

Well done, you just managed to make something beautiful and incredible sound totally revolting :lol:

A4000_Mad wrote:
 :popcorn:

Indeed. I am observing a Vapourer Moth which I am keeping in a glass with a breatheable cover and a load of leaves :-) It is starting to coccoon itself now. I'm thinking of setting up a webcam to take pictures every 10 seconds so I can make a high speed animation of the process.

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moto

[motorollin]

Ok I understand what happened, but why did they not evolve in to a different species? I still don't understand the evolutionary advantage of larvae which develop in to the mature adult rather than just being born as the butterfly in the first place.

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moto

[motorollin]

mel_zoom wrote:
The vast majority if not all insects have a similar larval stage - the eggs are too small to allow for the growth of a fully fledged insect in the same way as many higher order egg-laying creatures.

I think this is the answer to my question :-)

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moto

[motorollin]

bloodline wrote:
What is weird to think though, is that inside the catapillar are a few cells that do nothing, but have been their since it hatched from it's egg... then when the catapilla enters its cacoon, these cells then secrete enzymes that digest the rest of the catapillar... and the butterfly grows from these cells which feed off the catapillar... weird huh!

Revolting :lol: Does the caterpillar die then?

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moto

[motorollin]

I wonder why they evolved a larval phase rather than just laying bigger eggs with tiny, fully-formed butterflies inside?

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moto

[motorollin]

My Vapourer moth has emerged :banana: It's wingless so is a female. She has laid some eggs on one of the leaves. Is it usual for moths/butterflies/insects to lay eggs whether they are fertilised or not?

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moto

[motorollin]

Well regardless of why it happened, here is what emerged from the cocoon created by the caterpillar I caught. I have released her in to the garden now, so she is free to lay useless unfertilised eggs, and lie helplessly as predators consume her wingless body. Ahhh, the beauty of nature.

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moto

[motorollin]

I understand the functions of each stage in development and what part they play in the animal's life cycle. My question was more focussed on why this complex lifecycle evolved, rather than the larval form becoming extinct in favour of the better adapted adult form. I now know that this is because the eggs laid by the adults are too small for a smaller version of the adult creature, which is why the tiny larvae hatch and then grow.

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moto

[motorollin]

bloodline wrote:
If a fly doesn't lay it's eggs, they will hatch out inside the female and consume her.

Fascinating, but still,

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moto

[motorollin]

I understand that. I genuinely was fascinated by that, it was not a facetious comment :-)

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moto

[motorollin]

bloodline wrote:
No, I know! I'm excited by your thirst for knowledge, I felt it important to make that point. Please do read the "Selfish Gene"!

Just ordered from Amazon :-) I read the first few pages of the introduction and it sounded right up my street.

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moto

[motorollin]

Intriguing...

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moto

[motorollin]

I don't see how leaving parts behind would make a difference. If the larva has learned some behaviour, then this information would be stored in memory. Even if the brain of the larva remained intact and were re-used in the adult, presumably the digestion of the body would result in brain death since there would be no oxygen or nourishment supplied to the brain tissues once the larval body had been destroyed.

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moto