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ramriot t1_itbvn7t wrote

Reply to comment by SecretNature in is it the case that poisonous animals tend to be colourful and if so why is it that they tend to evolve to be colourful moreso then other animals? by HumbleProdiGenius

This ☝️ is the best answer, most of the others end up being teleological or anthropomorphic arguments.

An interesting since note is that once a boldly coloured hazardous population is present with its selective predators there is often a secondary evolutionary selection for any mutations that leads to other species beginning to resemble it.

Thus the possible evolution of non-stinging Hover Flys with bold black & yellow stripes that closely resemble those on wasps.

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SecretNature t1_itbys04 wrote

Yes, selection can also cause two hazardous species to end up looking like each other as negative interactions with either species is beneficial to both. Monarch butterflies and Viceroy butterflies are an example.

The example you cited with hover flies is Batesian mimicry while the butterfly example is called Müllerian mimicry in case someone wants to learn more.

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ramriot t1_itbzbtb wrote

Thanks for that, just reading through wikipedia on this, I love how the selection pressure is population sensitive. In that if the mimic starts to predominate over the model the whole thing falls apart.

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E_M_E_T t1_itd8osh wrote

I think that's a decent theory but it might have a big problem. If non-poisonous animals start to resemble poisonous ones, then the selection pressure for looking poisonous goes away, as there's only a limited amount of food out there and predators will inevitably realize that some of the colorful prey are tasty as well.

So if the Hover Fly evolution theory is true, then you have to either go with the assumption that food scarcity just isn't enough to push animals back towards older behavior, or you can assume that this trend towards colorful poisonous animals comes and goes in cycles.

Maybe the answer is that Earth's biodiversity reached some kind of equilibrium in the past and the number of new, colorful yet non-poisonous species equals the number of new, poisonous yet colorless species. So the generalization of "colorful animals are poisonous" is always true enough.

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ramriot t1_itdsx9e wrote

Yes, as someone else put it here about Betesian Mimicry the mimic will reach only a minority of the models population because it is becomes dominant the pressure goes away.

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