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Butterfly arrival in New Zealand

Axonly
Posts: 1,801
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2/12/2016 11:57:25 PM
Posted: 9 months ago
So, here in New Zealand, endemic/native butterflies only belong to the families "Nymphalidae" and "Lycaenidae", both of these families first appeared between 38-40 million years ago. New Zealand separated from Gondwanaland about 85 million years ago. No other families of butterfly exist in New Zealand (Excluding introduced ones). Additionally, many of these species are similar and are also native to Australia.

So, based on these facts, which of these statements is more likely to be true:

A: Butterflies from Australia drifted/flew over to NZ and colonized there, replacing the other butterfly species present at the time.

OR

B: Butterflies from Australia drifted/flew over to NZ and colonized alongside other NZ butterflies, but did not replace them.

Or are there other options I am missing?
Meh!
Mhykiel
Posts: 5,987
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2/13/2016 12:45:15 AM
Posted: 9 months ago
At 2/12/2016 11:57:25 PM, Axonly wrote:
So, here in New Zealand, endemic/native butterflies only belong to the families "Nymphalidae" and "Lycaenidae", both of these families first appeared between 38-40 million years ago. New Zealand separated from Gondwanaland about 85 million years ago. No other families of butterfly exist in New Zealand (Excluding introduced ones). Additionally, many of these species are similar and are also native to Australia.

So, based on these facts, which of these statements is more likely to be true:

A: Butterflies from Australia drifted/flew over to NZ and colonized there, replacing the other butterfly species present at the time.

OR

B: Butterflies from Australia drifted/flew over to NZ and colonized alongside other NZ butterflies, but did not replace them.

Or are there other options I am missing?

Well they didn't need to fly. Transmission could have been by eggs or cocoons.

Could have been butterflies emerged on NZ and went to Australia where some species found dominance that their ancestors couldn't find on NZ. vice versa for NZ butterflies emerging first in Australia.

Or when all other options don't seem to pan out Scientist like to use convergent evolution as an answer. 2 similar looking species with no relationship evolved the same feature. What's great is this has even been used to explain similar genetic structures of supposedly unrelated creatures. Such as in the exclusion of some endogenous retroviruses data found in 2 unrelated animals. But the rest of the data was sued to show ancestry.

Pretty much when it comes to evolution there is a "tool" to answer any scenario you want.
RuvDraba
Posts: 6,033
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2/13/2016 11:44:48 AM
Posted: 9 months ago
Axonly, I understand that the monarch butterfly known in both NZ and Australia [http://www.monarch.org.nz...], is actually native to the Americas. [http://monarchlab.org...]

It is believed to have dispersed elsewhere as late as the 1800s, or perhaps earlier. Monarchs are migratory (in New Zealand they migrate to winter in warmer parts) and in North America they can fly over 2,200km to migrate, so it may be possible that some actually did fly to other lands -- and this is supported by some monarchs spotted having been blown across the Atlantic to the UK coast.

However, they're dependent on milkweed plants to host the larva, and those plants have been spread by human action, which may account for why they didn't migrate much before the colonial expansions of the 19th century. But direct human action may have migrated some eggs or pupae too.

So there might be more than one story regarding the origin of NZ butterflies, depending on the species.

I hope that may help.
Axonly
Posts: 1,801
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2/14/2016 3:57:47 AM
Posted: 9 months ago
At 2/13/2016 11:44:48 AM, RuvDraba wrote:
Axonly, I understand that the monarch butterfly known in both NZ and Australia [http://www.monarch.org.nz...], is actually native to the Americas. [http://monarchlab.org...]

It is believed to have dispersed elsewhere as late as the 1800s, or perhaps earlier. Monarchs are migratory (in New Zealand they migrate to winter in warmer parts) and in North America they can fly over 2,200km to migrate, so it may be possible that some actually did fly to other lands -- and this is supported by some monarchs spotted having been blown across the Atlantic to the UK coast.

However, they're dependent on milkweed plants to host the larva, and those plants have been spread by human action, which may account for why they didn't migrate much before the colonial expansions of the 19th century. But direct human action may have migrated some eggs or pupae too.

So there might be more than one story regarding the origin of NZ butterflies, depending on the species.

I hope that may help.

I dont think I ever mentioned Monarchs? I did however say that I was excluding introduced species
Meh!
RuvDraba
Posts: 6,033
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2/14/2016 4:58:16 AM
Posted: 9 months ago
At 2/14/2016 3:57:47 AM, Axonly wrote:
[Monarchs as an example.]
There might be more than one story regarding the origin of NZ butterflies, depending on the species.
I don't think I ever mentioned Monarchs? I did however say that I was excluding introduced species

As per my example, what's interesting about the Monarch though is that it might not have been introduced. It may simply be that its preferred food-plant was.

A butterfly species can cross the Atlantic, and may well have crossed the Pacific too. That being so, what requires the ancestors of New Zealand natives to have come only from Australia? Certainly some Australian natives are present in New Zealand, but at least one Americas native has appeared too, with no present way of excluding that it flew there. If a butterfly can reach the geography, survive the climate and find something to eat on arrival, then it may well do so -- at which point it might begin to diversify.

You asked if you might have missed something. As I mentioned above, it seems to me that different species might have different stories.