Prehistoric origins of Troidini

[nomihoudai]

I was wondering about the prehistoric origins of the Troidini. I do remember that Ornithoptera and Troides got lumped, and more importantly, that Troides and Parides are more closely related than other Papilio genera. It kind of makes sense when looking at the wing shapes.

Now, recently I saw this very interesting YouTube video (no insects, but I invite anyone to watch it that has some spare time):



I wonder if the ancestors of Troidini came to Asia floating there through India, or if they took the route through Antarctica to Australia (See the video at t=14:49)? Any consensus on that?

[livingplanet3]

Apart from those you mentioned, the following genera are classified under Troidini as well -

Atrophaneura
Battus
Byasa
Cressida
Euryades
Losaria
Pachliopta
Pharmacophagus
Trogonoptera

Until recently, it hadn't occurred to me that the Battus philenor that I so often see in my yard are considered to be more closely related to birdwings than they are to my several other local species of swallowtails.

[nomihoudai]

Yes, Battus also likes to hang from plants when resting. It reminded me of birdwings when resting. Lycaenidae sleep in a different position.

I took this picture 2015 in the Attwater Prairie Chicken Reserve, West of Houston, TX.

[livingplanet3]

Yes, and the larvae and chrysalides of Battus are much more like those of Ornithoptera than of Papilio.

[Crake]

Jan 27, 2021 14:03:02 GMT -8 nomihoudai said:

I was wondering about the prehistoric origins of the Troidini. I do remember that Ornithoptera and Troides got lumped, and more importantly, that Troides and Parides are more closely related than other Papilio genera. It kind of makes sense when looking at the wing shapes.

Now, recently I saw this very interesting YouTube video (no insects, but I invite anyone to watch it that has some spare time):



I wonder if the ancestors of Troidini came to Asia floating there through India, or if they took the route through Antarctica to Australia (See the video at t=14:49)? Any consensus on that?

It was a bit of an "AHA" moment when I noticed the resemblance between Parides and Troides. An excellent example is Parides chabrias; the body size/wing proportions are quite "birdwing-esque".

[nomihoudai]

The resemblance in caterpillars is indeed striking for them. I did spend some time this evening and wrote a computer program to download me pictures of caterpillars for most species groups. It was interesting, but after seeing so many pictures it looks like the features that separate them are not always that clear to me. Still, there is plenty of resemblance.

Considering the topic, Pharmacophagus antenor confuses me right now. How and when did it get to Madagascar? Is it the proof that India was important in the evolution of Troidini or did it most likely all happen before Gondwana broke into pieces? I forgot the conclusion of the existing papers.

[Crake]

Jan 27, 2021 20:15:38 GMT -8 nomihoudai said:

The resemblance in caterpillars is indeed striking for them. I did spend some time this evening and wrote a computer program to download me pictures of caterpillars for most species groups. It was interesting, but after seeing so many pictures it looks like the features that separate them are not always that clear to me. Still, there is plenty of resemblance.

Considering the topic, Pharmacophagus antenor confuses me right now. How and when did it get to Madagascar? Is it the proof that India was important in the evolution of Troidini or did it most likely all happen before Gondwana broke into pieces? I forgot the conclusion of the existing papers.

I reviewed some of the papers, and I found the study below to be the most informative. It's concluded that Pharmacophagus probably dispersed to Madagascar from India not through vicariance, but transoceanic dispersion after the breakup of Gondwana. 


biodiversitygenomics.net/site/wp-content/uploads/2016/01/2011%20-%20Simonsen%20-%20Phylogenetics%20and%20divergence.pdf

[Adam Cotton]

Simonsen et al. is a bit older, and not directly aimed at Troidini.

Here is a paper about Neoptropical Troidini:

bmcecolevol.biomedcentral.com/articles/10.1186/1471-2148-12-82

Condamine et al. 2012. Biogeographic and diversification patterns of Neotropical Troidini butterflies (Papilionidae) support a museum model of diversity dynamics for Amazonia.

And a paper about global biogeography of Papilionidae:

onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2699.2012.02787.x

Condamine et al. 2013. Global biogeographical pattern of swallowtail diversification demonstrates alternative colonization routes in the Northern and Southern hemispheres.

Try this paper about origin of birdwings:

www.nature.com/articles/srep11860

Condamine et al. 2015. Deciphering the evolution of birdwing butterflies 150 years after Alfred Russel Wallace.

All of these pdfs are open access, click the download link on the page.

Adam.

[Adam Cotton]

nomihoudai wrote
"I do remember that Ornithoptera and Troides got lumped"

They have been split again

I should also mention that similarities between certain Parides and Troides spp is convergent, rather than evidence of a close relationship between species.

The ancestor of Battus separated from the rest of the Troidini first and then the ancestor of Pharmacophagus. Subsequently the rest of the Troidini split into two main lineages, the first wholly Asian containing Losaria + Pachliopta and Atrophaneura + Byasa; and the second lineage split into two branches between 30-40 million years ago. The first branch contained ancestors of Parides, Cressida and Euryades and the second branch became the birdwings.

Adam.

[Adam Cotton]

Crake wrote
"It's concluded that Pharmacophagus probably dispersed to Madagascar from India not through vicariance, but transoceanic dispersion after the breakup of Gondwana."

Yes, that is correct. Other studies also showed that the ancestor of Pharmacophagus diverged well after Gondwanaland broke up, and after Madagascar split away.

Another interesting question which has not yet been answered is why Pharmacophagus is restricted to Madagascar when its larval foodplant, Aristolochia albida, occurs across tropical Africa. Many other butterfly species have crossed between Madagascar and mainland Africa and back in the past resulting in multiple cases of speciation, but there are no species of Troidini in mainland Africa at all.

Adam.

[nomihoudai]

Thanks to everyone replying to this thread. Thank you very much for the extensive list Adam. I spent today reading the papers. Long story short it looks like there is a lot of ideas and theories out there. Some of them looking at an earlier splitting of the subfamilies (+-50Ma), and the other claiming that there was very recent (12Ma to 2Ma) diversification and that the species spread along coasts etc. to every place where they are found today.

Somehow I still wonder if Troidini did split off of ancestral Papilionidae earlier than 50Ma and that they stayed around tropical Proto Australia/India. If then the ancestors of Red-bodied swallowtails (Atrophaneura, Byasa, Losaria, Pachliopta) would have been on India together with the earlier version of Troides they would have had a blast when reaching the western Palearctic. Ornithoptera could have taken the other route with Australia. I liked that this idea was in parts also mentioned in a sentence in Simonsen et al.. Pharmacophagus could have reached Madagascar in that scenario either by dispersion or vicariance. Anyway, despite being a trained scientist I will probably not look into it at the same level of depth than others have worked on their theories.

The papers by Codamine have many good points (they favor much younger diversification events), still I would have liked if they also included Graphium and a deeper look at host plants.

In the end I feel like both ideas in their entirety are very different. If there is two different sets of ideas the correct entire picture most likely is a mixture of both.

[nomihoudai]

p.S. I am glad that Ornithoptera is back. The name lumping never made sense to me.

[Adam Cotton]

Here's a new publication which looks at both Papilionidae and larval foodplants:

www.nature.com/articles/s41467-020-20507-3
(open access)

Allio et al. 2021. Genome-wide macroevolutionary signatures of key innovations in butterflies colonizing new host plants.

Adam.

[Adam Cotton]

Fabien Condamine gave a web presentation on the new paper organised by McGuire (recordings of other seminars are available here www.floridamuseum.ufl.edu/nhdept/seminars/) on January 26th.

The 1 hour presentation can be watched here:
ufl.zoom.us/rec/share/UURo9tP4YYCdzHzpTRgQfUaEmxNGi9mogdTYNjBZICOaIzmOKdh59ghOK8sPqL6e.8tdBy2uG29qkBVc2?startTime=1611680378000

Also the 63 slides used in this presentation can be downloaded as a powerpoint file here:
www.dropbox.com/s/wlzk2wgz63mzm8x/Seminar%20McGuire%20-%202021.pptx?dl=0

Adam.

[Adam Cotton]

Jan 28, 2021 19:14:27 GMT -8 nomihoudai said:

p.S. I am glad that Ornithoptera is back. The name lumping never made sense to me.

Troides and Ornithoptera are clearly sister monophyletic groups with a common ancestor which was sister to the ancestor of Trogonoptera.

Unlike species, (which can be tested for validity by several methods - can they interbreed to produce fertile offspring, are they morphologically different, are their DNA sequences very close or not?) where to separate genera is completely subjective. One person may consider Troides and Ornithoptera as separate genera, whereas another treat them as subgenera of a single genus. It is worth bearing in mind that neither person would be 'wrong'. It is only wrong to combine two groups of species in a single genus while excluding some species which evolved within the group.

So for example, if someone combined Trogonoptera and Ornithoptera in a single genus, but kept Troides as a separate genus that would be incorrect. At the same time, treating all 3 as separate genera would be just as valid as lumping them all into a single genus. Where to split monophyletic groups into genera, subgenera, tribes and even families is absolutely subjective, but is normally based on some form of evidence, such as morphological characters shared by all members of the group but not by those outside it. What rank a taxonomist gives a particular group is subjective, but hopefully the ranks given are equivalent across the various taxa.

As an extreme example of this, it would be acceptable for an author to treat each species of Troides as belonging to a separate genus, as long as he treated all species similarly. Of course whether other people accept his classification or not is up to each individual since it is based wholly on subjective opinion. In this particular case I expect the classification would be rejected by most if not all readers of the author's work.

To summarise, whether sister groups are treated as separate genera or lumped together in a single genus is completely subjective and different treatments are neither 'right' or 'wrong', as long as they do not include unrelated taxa or exclude taxa which belong within the genus/genera.

Adam.