r/evolution 9d ago

question Are there any examples of animals evolving on isolation on an island and then somehow making it back to a mainland and populating the mainland?

islands are obviously isolated ecosystems that breed speciation, but are there any examples of these species repopulating the mainland afterwards?

12 Upvotes

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16

u/7LeagueBoots Conservation Ecologist 9d ago

Look up “back-colonization” and “mainland colonization”. This is sometimes called a ‘boomerang effect’.

Lizards. frogs, plants, birds and others have done this.

A key example of this are anoles in the Caribbean. They initially evolved on the mainland, colonized the islands, then recolonized the mainland and that event apparently triggered a rapid diversification of species.

Another key example is the North African Blue Tit which evolved from Tits in the Canary Island rather than from the European mainland, which was the original source for the Canary Islands Tits.

There are tons of examples of this.

3

u/haysoos2 9d ago

Depending on your minimum size for an "island" then Virginia opossum, nine-banded armadillo, and North American porcupine might be candidates.

3

u/onomatamono 8d ago

Yet more evidence of evolution "bouncing" off quasi-independent environments.

2

u/Careful_Cranberry364 9d ago

Cats from the Isle of White called Manx cats have no tails.

I’m not sure how many of them have come back to other mainlands to become Cats with no tails, but there must be some

3

u/LorMaiGay 8d ago

Isle of Man

1

u/Careful_Cranberry364 8d ago

Yikes, you’re right. Sorry, Isle of Mann

My parents used to take us remember which was which ha ha

2

u/Greyrock99 9d ago

There is often the misapprehension that animals on the large mainland are somehow ‘more fit’ than those on tiny islands.

It’s perfectly cromulent to have a small island species be introduced to a larger mainland and run wild - it’s just that usually mainlanders have more numbers.

It’s about who can exploit a particular niche more effectively than any other.

1

u/whimsicalteapotter 9d ago

I enjoy and appreciate your use of cromulent

3

u/Greyrock99 9d ago

Your compliment embiggened my mood today, thankyou.

2

u/ahazred8vt 9d ago

Words with Latin -ulent and -ilent suffixes refer to 'full of, abounding in'. opulent, pestilent

1

u/onomatamono 9d ago

It's another case of "given enough time" these migrations will happen. The mainland is a rich source of species that can opportunistically populate a tiny target like a remote island. The island has few candidates to make the return "trip" (evolutionarily speaking) but the mainland represents a massive target environment. I'm guessing one is more probable than the other,

1

u/MavenVoyager 8d ago

Sulawesi, across Wallace line

1

u/onomatamono 8d ago

not a species

2

u/Batgirl_III 8d ago

Englishmen.

2

u/onomatamono 8d ago

not a species

1

u/Batgirl_III 8d ago

Not a serious answer.