Bombus ashtoni vs Bombus bohemicus in North America

With a recent discussion on an observation regarding whether B. ashtoni is merged or not with B. bohemicus, I wanted to collate my thoughts in a google document on the matter for future reference.

For a TL;DR, I think that merging these two is premature at this time, and many authors saying they are merged are misquoting sources and referencing a field guide that gives no references or methods to back up the claim.

Edit: I had quite a bit of weigh in on this (surprising as I usually don't on journal posts) including Dr. Paul Williams (towards the bottom). To get both sides of the issue, I would recommend that anyone reading this article also read the comments, in particular Dr. Williams'. I still have the same opinion that I had before (that the current published data does not support synonymy), but the added details were enlightening and that would be a good way to see both sides.

Bombus ashtoni and Why It's Not Merged with Bombus bohemicus (yet)

Publicado el marzo 8, 2023 12:46 TARDE por neylon neylon

Comentarios

Interesting post. Since I was involved in a related discussion on an observation page, I'll add a few points, and discussion could be held here, on the observation page, or wherever would be best. My reply is lengthy for a comment (written more like the post) so I'll add it in a few parts below.

Publicado por bdagley hace más de 1 año

I don't claim to have fully studied the question of whether the two species should be merged yet, partly because I don't have Williams's bumblebee book on hand, although have read it. I'm also in a sense replying to what was said on the observation and here as if it was combined, and mostly making arguments about whether the species have been merged (vs. whether they should have been merged). I use merge as a shorthand for synonymized throughout.

This discussion started when you expressed doubts about some articles saying the species were merged in literature by Williams, with regard to what Williams actually wrote or intended. I then briefly emailed Williams, who said he does indeed believe he synonymized the species (I don’t think he was aware anyone was debating it, I didn’t mention a debate). With that in mind, one correction seems to be that the additional articles that claimed that Williams merged the species were correct (whether or not they were incorrect about any other related matters). Note that for them to be correct doesn't require the merge itself to have arguably been justified, I just mean they are correctly retelling what Williams did in literature.

I haven't looked into the other inaccuracies you mention about the other authors, although can possibly grant you some may have occurred. But for me, the main issue mostly concerns what Williams did, as explained, and it seems misleading to fault other authors for (correctly) stating that Williams merged the species. We also should ensure we don't conflate the later publications by other authors with the justification for the merge, since the merge happened earlier.

Focusing on Williams (2013, 2014, and any additional publications) specifically now, you say that the evidence wasn't provided or demonstrated for the merge. I can't easily check this at the moment without the book on hand, but the claim seems somewhat surprising. Is it certain that such evidence/results aren't or weren't provided in the publications, or through a related for example online source, etc.? Even in the event you thought the evidence was left out, another relevant question would seem to be would that evidence/results be provided to authors who requested it in principle, which I'd expect to be yes. If relevant re: the original/precise sources for the merge, what Williams specifically said was "ashtoni is shown as a synonym of bohemicus on page 46 of the PUP bumblebee guide, which is justified on page 161."

This also relates to how you compared this merge to the Bombus fervidus paper which merged other species, which you said is what a real or full merge would've looked like. That is often although not always the case in my opinion, and so the merge at question here not having a fuller publication dedicated to it on it's own doesn’t negate it or mean it didn't occur. Where we may agree on this is that taxonomists are required to give reasoning and to note when they are merging species, although arguably that did occur here, with the references to page 46 and 161. I do also agree that clearer statements or longer or more dedicated publications for merges can be ideal, although not mandatory.

You've also argued that the language used in the Williams book expressed uncertainty or wasn't clearcut, although I don't entirely agree. For one thing, somewhat uncertain phrasing is almost always used when discussing genetic results, even when the overall ending conclusion is high confidence in the results. Another factor is we can't simply take a sentence or paragraph from a source in isolation and interpret things from it, we have to consider everything that was written and in chronological order, to understand. And since both Williams (in correspondence) and the additional sources citing him speak of the merge in a confident/fact-of-the-matter manner, it doesn't seem accurate to interpret Williams to have been uncertain in the publication. Although I don't have all the excerpts in front of me at the moment, I also recall that part of the excerpts that you said expressed uncertainty (by Williams and/or other authors) actually included statements made with more certainty as well. For example, one author spoke about how the two species have been treated differently in various ways by different authors over chronological time, and you said their language seemed uncertain, but the end of their excerpt simply stated that Williams did merge the species without making any caveat, so doesn’t resemble uncertainty to me. So, I disagree that the publications by Williams or those who cited him as merging the species overall spoke in an uncertain manner in the way implied. (cont.)

Publicado por bdagley hace más de 1 año

Lastly, although it seems somewhat self-evident, I find it confusing how you seem to disagree with what Williams later clarified, given that at the beginning of the discussion it seemed that everyone trusted his classification whatever it may turn out to be confirmed to be, and we since learned he considers himself to have merged the species. It can also be considered that Williams may have been aware or even have even been consulted to review some of the other articles that cited him, and for example he or others very likely would’ve publicly later noted if the latter truly had erroneously written about him merging the species. In other words, absence of debate or correction of that fact in the literature to date is another indication that it wasn’t actually an error, as well as (potentially) that many authors agree with the merge, considering it the prevailing view. As a side note, note that authors sometimes may agree (in not disagreeing) with another author’s classification without necessarily analyzing or scrutinizing it. And so, an author citing another’s finding or classification in no way necessarily affects or weakens the original, since it wasn’t related to the latter citing authors.

Anyway, there is another aspect of this, which is where your own view or anyone’s may most applicably fit. Which is that even a true merge in taxonomic literature isn’t always adopted by all authors. Yet, authors are supposed to indicate and explain why in writing if they disagree (in the sense that all of these discussions are mostly occurring in the literature/academia). I’d suggest that the conclusion that the merge was premature may be premature. In that, factors such as the genetic evidence (which was claimed to be omitted/incomplete in the publication) haven’t been discussed in much detail in judging the merge to be premature. I’d also expect someone disagreeing with the merge to for example access or request that evidence to examine first as part of that process, as well as potentially examine specimens, although anyone is free to conclude against the merge or in thinking it’s premature.

In short, it’s a complicated process to make the case both for as well as against the merge, but overall in general merges in literature aren’t usually so easily dismissed, and there is a meaning to the statement that the merge did occur. Also, the source and author are well-regarded and trusted, although it’s still ideal and fair to evaluate the evidence or reasoning of any source.

I’d rephrase what happened in lit. very similarly to what Williams and those authors said, which is that Williams synonymized the species. It’s informative to phrase it that way, because then someone taking your position for example could write something like Williams merged the species, although I haven’t accepted that synonymy yet for such and such reasons. Actually, sometimes taxonomists will phrase this as that someone synonymized two species and so that they are hereby resurrecting or removing them from synonymy in disagreeing. In that way, authors can reflect what happened (Williams once synonymized the species) but also can discuss whether they now agree or disagree.

Lastly, I note again that much of what I’ve written here are counterpoints to some of the claims made, although I haven’t actually set out to make a full case for the evidence of merging the two species themselves at this time. I’m mostly focusing on what happened in the literature (that they were merged), since you originally seemed to state or assume that they were never merged. So, the somewhat separate but related question of whether the species should be synonymized is still somewhat open to discussion, although I believe some corrections as given are justified to make in clarifying what happened in the literature.

For consideration to merge the species, I expect that there may not currently be enough of a consensus on iNat to propose that taxon change at this time, although would currently side toward the merge, partly because the source is regarded as very reliable and the evidence does suggest the two taxa are closely conspecific. A final thing to keep in mind is that occasionally even valid merges or splits are made in literature that later turn out to be modified again (e.g. split after a merge or vice versa), and therefore to consider accepting a synonymy itself doesn’t necessarily require perfect knowledge and confidence that the taxon concept will never change again.

Publicado por bdagley hace más de 1 año

Some thoughts:

"ashtoni is shown as a synonym of bohemicus on page 46 of the PUP bumblebee guide, which is justified on page 161."

What does Williams et al (2014) actually say?

Page 46: Lists ashtoni as a synonym of bohemicus:
"Bombus bohemicus Seidl, 1837
_____ashtoni (Cresson, 1864 [Apathus])"

Page 161:"Evidence from morphology and DNA barcodes supports a close relationship between B. ashtoni from North America and B. bohemicus from Europe and Asia, which appear to be parts of the same species."

Now, to get very pedantic about it, consider Williams et al. (2014) to have treated ashtoni as a synonym of bohemicus rather than synonymized ashtoni under bohemicus. This is because there is no statement indicating "new synonym" etc.

In my opinion, this leaves a lot of wiggle room for people to treat ashtoni as distinct.

Without some sort of action statement synonymizing ashtoni under bohemicus, along with the continued scientific works treating ashtoni as distinct including the bees of MA by Veit et al. 2021 and my own bees of MN (in press in Zootaxa), I think they should remain separate.

Publicado por zportman hace más de 1 año

Thing is, it doesn't matter what Williams said in a communication or what he thinks regarding a merge, because that's not what these authors are citing. They're citing the 2014 book, which I quoted word for word in my post and Dr Portman did as well (adding the section on pg 46), which doesn't supply any details regarding synonymy. To speak facetiously, in essence he said: they're the same, trust me I did tests. Also if it took an entire other article to merge fernaldae/flavidus, why would the exact same wording from Williams merge these other species?

At this point, the literature doesn't support merging, if Williams has the data supporting this merge, then I eagerly await its publication

Publicado por neylon hace más de 1 año

Well, as I said I don't have the book in front of me, although have read it, although not with specific focus on this question at the time. One other thing there to add is that the book was a multi-author publication and one of the most influential bee books of all time I think. Now, about the evidence, unfortunately I don't have all of the passages on hand, but am just confused that you seem to think evidence is omitted or something. If the authors made reference to any evidence, it probably does exist and they would send it. I recall one of the citations of Williams publications also making reference to some online source Williams (2020). So, I'm suggesting that if you think evidence was mentioned but omitted that it possibly exist somewhere, or could be requested from the authors. Also about evidence, bear in mind that some authors are also including as part of their reasoning or evidence the evidence from past studies by other authors, for example in the excerpt from one of the papers where they gave a timeline of the different classifications authors have used over years.

I do agree that this situation is atypical, in that Williams et al. didn't write "new synonym," etc., although subsequent citations to the work did directly characterize it as that the two species had been synonymized. Also, there has been no published disagreement or questioning of the Williams et al. merge in literature that I'm aware of. The evidence matter still seems unclear to me. It seems unlikely that a coathored book that probably was reviewed would make many simple mistakes, such as referring to evidence but it not being present. So, I'd say there's at least more to look into regarding the evidence rather than assume.

People earlier also seemed to assume that Williams would agree the species weren't merged if asked, but he said the opposite. The fact that he thinks they were merged does matter. In any case, the merge was somewhat atypical/incomplete, and so is somewhat open to further question or review. I think if anyone here wanted to work specifically in this area, they may consider doing further study or expressing their view in a publication, because many authors wouldn't be aware of the disagreement otherwise, because taxonomy is only revised in the literature.

Also to clarify, I'm not necessarily asking for a taxon change, although would support one in the chance there became more agreement. Overall in summarizing on some of these matters, I'd still to some extent conclude that Williams et al. at least intended to synonymize the species (in one or various sources, the 2014 book, possibly also the 2020 website), although the manner seems somewhat atypical or incomplete, and you two have now said you potentially disagree or think merging them would be premature. So, I'd ideally recommend further study and discussion into some of the unclear issues such as the evidence, including possibly discussing your disagreements with Williams or related authors (I only asked him if the species are considered merged or not because some of the identifiers are wondering).

As for what to do now, in some senses some authors (maybe most) already assume the species are synonymized. So, that's what I meant when I said that the Calgary researchers who believed they were synonymized aren't necessarily incorrect. It is overall fair for them to interpret the literature that way, and as we've now seen it turns out the answer is even more complicated and Williams's view was opposite to what some expected. So, I'd no longer phrase it so simply as are they merged or not, because the matter is clearly disputed and/or unclear, although (part of my point) has only been regarded with confidence in the post-Williams et al. literature itself so far. Given that the situation is somewhat unclear, I agree that the two species don't need to be merged on iNaturalist right now, although with the caveat that in some senses or interpretations they were synonymized in literature, in an atypical way that you've now also disputed for multiple reasons.

I'm also curious what anyone makes of the concept of ashtoni being a subspecies of bohemicus? Which apparently has been used by some authors, because some websites currently list the taxon as the subspecies.

Publicado por bdagley hace más de 1 año

When Sikes and Rykken referred to Williams 2020, they were referring to the online catalog https://www.nhm.ac.uk/research-curation/research/projects/bombus/subgenericlist.html section on bohemicus https://www.nhm.ac.uk/research-curation/research/projects/bombus/ps.html#bohemicus from site images of male genitalia https://www.nhm.ac.uk/research-curation/research/projects/bombus/Ps/mg_ps.html#bohemicus In essence, says the same thing as the book.

The evidence may be out there, but it isn't in the sources being quoted by the various authors, and they didn't do the examination themselves. If they had, then referring to Williams' and Cameron's papers would have been in the context of indicating the history of the taxonomic change and then would have gone into the examination methods. In which case, I wouldn't have written this. It would be on others to judge the methods.

Publicado por neylon hace más de 1 año

"the book was a multi-author publication and one of the most influential bee books of all time I think"

It is not a peer-reviewed journal article.

The maps have many errors.

Publicado por johnascher hace más de 1 año

An unqualified statement as a pers. comm. does not change the fact noted by @neylon and @zportman that what was published was qualified or ambiguous

Publicado por johnascher hace más de 1 año

You missed that I above came to agree with them that it was "atypical, incomplete, and somewhat unclear," however I have additionally made some useful corrections in the process, and some of the original claims some made turned out to be incorrect, although I found the entire discussion useful or educating for all of us. I also have largely come to converge upon the same views as the others that we don't want to make a taxon change on iNat now given the complexity, so I actually have thought that I'm mostly in agreement with the others at this point. It's best not to overly simplify issues. Anyway, I'll also remind you all that in a good way I do always consider our discussions before making taxon changes, and wouldn't make any taxon change on my own if everyone else disagreed. So, we can discuss or debate things with no urgency, since I don't those big changes on my own.

Publicado por bdagley hace más de 1 año

I should mention that while I disagree with how Williams "synonymized" (by the way, I hate that word, I have typed it a lot over the last few days and still can't get the spelling right), I am not criticizing him, I am criticizing the authors referring to things that aren't present in his work.

On the incredibly slim chance that Paul Williams reads this, we carry BB of NA at the store, and I have sold quite a number of copies over the years. Not to mention all the people on here I've encouraged to buy a copy. My own copy is heavily dog-eared with a broken spine.

The fact that the book is important from the standpoint of making Bees accessible to the general public and is an incredibly useful resource doesn't mean it is without flaws and without reproach.

Publicado por neylon hace más de 1 año

It is indeed a great book (highly recommended).

As noted by Zach, the main reason to be especially careful about the taxonomy of this species (or species pair) are the potential implications for conservation of North American populations (i.e. ashtoni) which have declined precipitously whereas European populations (bohemicus sensu stricto) have not.

Publicado por johnascher hace más de 1 año

@johnascher @bdagley @zportman Thanks to everyone for reading and discussing. I thoroughly enjoyed it.

Publicado por neylon hace más de 1 año

1/3 Hello – and many thanks Rich for pointing me to this discussion. I am very glad to help to clarify if I can. It would be possible to write long reviews of the history of people’s treatments of North American bumblebee species and of the global status of bumblebees of the bohemicus-complex. Right now, I am keen to try to help clarify at least my contribution on these bees through the BBNA here.

In summary, as far as I was aware in 2014 (the BBNA book), and still now, in my view the weight of evidence supports the name ashtoni as applying to part of the same global species population as the name bohemicus (a biological issue). Therefore I regarded ashtoni as a junior synonym of bohemicus, because of the priority of the latter name by date of available publication (a nomenclatural issue). Such decisions on species extent depend on the species concept adopted and on the evidence available relating to that concept. Interpretations of either of these may change through time, especially as more information becomes available.

More to follow...

Publicado por paulwilliamsnhm hace alrededor de 1 año

2/3
BIOLOGY
I am assuming for the present that species are real observable entities in nature and that they are out there to be discovered or recognised. The BBNA book was necessarily a compromise and one of the things that could have been more fully explained there is ideas of what a species is, the underlying species concept. If it is of interest, my views on the history of species concepts as applied to bumblebees can be found at https://doi.org/10.1093/zoolinnean/zlab123. I have published formal revisions of several bumblebee subgenera and species groups (others are in preparation), which give more details of how this can be applied in practice to real examples (but see e.g. https://doi.org/10.5852/ejt.2020.719.1107).

In short, for bohemicus/ashtoni (let’s call it the bohemicus-complex), page 161 of the BBNA book refers to how the interpretation of these bees was based on ‘Evidence from morphology and DNA barcodes’. On page 48 it mentions how this includes ‘new evidence from DNA barcodes (from the COI gene) provides stronger support for interpretations of their [bumblebee taxa] status as parts of species more widespread elsewhere in the world’.

For the BBNA book, all of the North American bumblebee species were studied in detail, afresh, for both morphological and barcode variation, as part of a long-term project studying this variation for all bumblebee species world-wide (this included revising all of the sequences in BOLD at the time in collaboration with CCDB). I had worked with Sydney Cameron and Heather Hines on other genes previously, but COI sequences can be aligned with greater certainty and, because COI (which they did not use) is a faster-evolving gene, it can be more informative for closely related taxa, near the rank of species. My recent revisions have focussed on looking for species coalescents in the COI gene. The coalescent approach is seen as better than simply measuring divergence in one or more genes (e.g. using a ‘barcoding gap’) or simple genomic approaches, because single-gene species coalescents are direct evidence of the evolutionary independence of lineages that is at the centre of the current (EIL) species concept. There are potential pitfalls, of course, which are discussed in the papers above. In all of these studies an integrative approach is taken, so that COI coalescents are only accepted as supporting species when they coincide with differences in morphological diagnoses.

Regarding morphology, I have been looking at these bees in faunal studies for North America, Europe, Russia, Mongolia, China and the Himalaya (e.g. recent treatments by me include https://doi.org/10.1017/S1477200008002843 https://www.nhm.ac.uk/research-curation/research/projects/bombus/Williams11_KUE.pdf https://doi.org/10.11646/zootaxa.3830.1.1). There is always more to learn, of course! To show that the species interpretations in the BBNA are not immune to new evidence, please see e.g. https://doi.org/10.11646/zootaxa.4625.1.1 https://doi.org/10.1080/00222933.2021.1900444

The interpretation in the BBNA (and now) is that although these bohemicus-complex bees show variation, the weight of evidence is that there is a single species spanning North America, Asia, and Europe and that this includes the type specimens for both of the named taxa ashtoni and bohemicus. If on page 161 the word ‘appear’ conveys uncertainty, then this is only because all interpretations of species always remain subject to new evidence, to be interpreted in the context of whichever species concept is accepted. Note also that the species have not ‘merged’ – it is the interpretation here of what is recognised here as an objective reality of the species that has changed (rightly or wrongly). (Another consequence is that if species are recognised as an objective evolutionary reality, then necessarily they are not arbitrary units of convenience that can be modified to meet conservation values, but rather as real individuals they may have consequences for conservation values.)

As recently as 2018, I had a printout of a complete tree for all of the bumblebee COI barcodes in BOLD, as part of a joint project with CCDB. In this tree, the North American ‘ashtoni’ sequences and the European ‘bohemicus’ sequences all came out as intermixed in the same group. This is again consistent with the two taxa being conspecific.

More to follow...

Publicado por paulwilliamsnhm hace alrededor de 1 año

3/3
NOMENCLATURE
In contrast, there should be no uncertainty in reading the BBNA book in how the conclusion on species status was interpreted for nomenclature. On page 46, the legend for the checklist table explicitly states that valid names for species are given in bold with synonyms given below them. The table legend adds that a ‘?’ is used ‘when synonymy is uncertain’. Therefore, in this list, ashtoni is unequivocally given as a synonym of bohemicus, just as fernaldae is given as a synonym of flavidus. This can be contrasted with the case of intrudens, which is given as an uncertain synonym of variabilis (I have seen barcodes for intrudens but not for variabilis, for which only the morphology has been compared).

The familiar point is that we use the oldest available name as the valid name for a species (ICZN, 1999: Article 23). So Bombus ashtoni (Cresson, 1864) becomes a junior synonym of Bombus bohemicus Seidl, 1837, when both types are interpreted to have come from the same species population. Although there were actually referees commissioned by PUP for the BBNA, referees are not required by ICZN in order to publish nomenclatural actions, only that the publication should be available in the sense of ICZN. And although it might be desirable to highlight such nomenclatural actions with e.g. ‘syn. n.’, this is also not required by ICZN.

(It was good to see that the act of synonymisation of fernaldae with flavidus in BBNA was agreed by L’homme et al. (2021), but their action was not original on this nomenclatural point.)

Ultimately all of this work is the published interpretations of various authors, to be accepted, or not, by others, as they consider appropriate.

I’m sure that there is a lot more that could be said about this, so please let me know what is unclear, or what new information is available to change our interpretations. Please use email, because regrettably I do not routinely read iNaturalist.

Publicado por paulwilliamsnhm hace alrededor de 1 año

Thank you very much for taking the time to read give such an extensive response. By the way, I do have a Researchgate request in for the March 2022 article you mention, I'd very much like to read it.

I've read the response a couple of times, and I still stand by the main point of what I wrote: The authors stating that ashtoni is synonymized under bohemicus, are not listing sources that demonstrate that. They are only listing sources that state or suggest it themselves.

The main point that I make here is not that ashtoni and bohemicus are separate species (I state this in the document), I cannot say that one way or the other. However, the papers that I mention are telling me that I can find the details for the change in BBNA, and the details are not there. Therefore the point still stands, everyone is saying it, no one is showing it.

Publicado por neylon hace alrededor de 1 año

I'm not quite sure what kind of details you were expecting to see in the BBNA text. I could of course describe how I work as a taxonomist e.g. the hours of examining bees down the microscope looking at the subtleties of exoskeleton sculpturing and the many iterations of genetic tree building. Would a barcode tree showing the two taxa together with no difference between them help? I am very happy to engage with anyone who believes that there are two clear species here, having looked at specimens from across the global range of the complex. As a taxonomist who has spent 40 years looking at bumblebees, I have so far found no evidence to recognise two different species in this case, and have therefore synonymised the two nominal taxa. I think the onus is actually on those who wish to make such a distinction to explain what the distinction is.

Especially in a guide book, as in many taxonomic papers, it has been common practice to simply report an original inference that two taxa are conspecific with a mention of the kinds of evidence studied, as on page 161 of BBNA. There are several similar examples in Thorp, Horning & Dunning (1983) on the bumblebees of California (pages 32, 37, 45, 50, 52). I hope that my comment goes some way towards answering this, at least in demonstrating that a lot of work has been done in examining these bees world-wide.

I will search for the ResearchGate request now, but if you don't receive a copy today, please do send me an email so that I can send it directly.

Happy #TaxonomistAppreciationDay!
Paul

Publicado por paulwilliamsnhm hace alrededor de 1 año

Thanks for adding the clarifying notes, and happy Taxonomist day @paulwilliamsnhm

One minor note is a couple of us used the word "merge" but only meant it as a shorthand for synonymized.

I had made many of the same points you made, earlier in the discussion, including that the written language wasn't uncertain, that the book had been reviewed, that writing syn. nov. isn't necessary, etc., and most importantly that the justification for synonymizing was given. I made the point that the genetic data was available and that you would likely share it if authors asked. Maybe it would help further clarify to link to exact pages regarding the COI sequences? These are the results I get on BOLD when searching the taxa. I downloaded the data as a KML file and opened it in Excel, and it includes nucleotide sequences and additional information.
Bombus bohemicus
Bombus ashtoni

I wonder if BLAST could be used so we can see how similar they are? (https://blast.ncbi.nlm.nih.gov/Blast.cgi)

Brian

Publicado por bdagley hace alrededor de 1 año

Thanks Brian - good to hear from you. For assembling barcodes, the largest sample I have examined was from BOLD in 2018 by arrangement with CCDB, but I don't own these sequences and unfortunately I would not be free to distribute them even if I had them here. However, I'm sure many sequences are publicly available in BOLD and you would then be able to download them for analysis. Analysing them should be relatively straightforward, although there a number of issues of which to beware to avoid the familiar problems (misidentifications, numts, minimum selection of species to include, unique haplotypes, appropriate techniques for evolutionary trees, etc.). Ideally one would also contact people around the world in order to achieve an even sampling from across the range of the taxa of interest. Building up a good reliable sample can take a while of course (which is why some revisions can take ten years or more!).

BLAST should certainly be used to check for misidentifications. However, percentage sequence divergence (or similar metrics) does not relate in a simple way to current species concepts, especially because of the complications that can arise from differences in species range sizes and their consequences for levels of intraspecific variation. This is why reliable evolutionary trees (e.g. MrBayes or BEAST) coupled with species coalescent analyses (PTP or GMYC) are more appropriate and more closely related to the EIL species concept. If you need any help, please let me know.

Paul

Publicado por paulwilliamsnhm hace alrededor de 1 año

Thanks, that sounds like it would be a large project so I don't plan to undertake it currently.

Publicado por bdagley hace alrededor de 1 año

In case of interest, after Seidl (1837) described bohemicus, neither Cresson (1864) in describing ashtoni nor Franklin (1913) in revising North American bumblebees (including ashtoni) actually mentioned bohemicus. So unless it has been mentioned somewhere else (I haven't re-checked the many other references today), it seems that ashtoni may have been described in ignorance of bohemicus and, at that time, no-one had considered the possibility that the two might be conspecific.

The first mentions of the possibility that bohemicus and ashtoni might be conspecific seem to be by me in (Williams 1991: page 46) and by Cameron et al. (2007: page 20), but neither study had sufficient evidence to be confident (evidence of absence of difference is always difficult). The COI barcode data evidence used for the BBNA (2014), of finding zero or very few base-pair differences between the two taxa (which formed a single group on the COI tree), was much clearer (bearing in mind that COI is a particularly fast-evolving gene and should reflect any differences). When by 2018 a total of 8861 bumblebee barcodes had been re-examined from BOLD, including 31 bohemicus and 15 ashtoni (these are not abundant bumblebees), this evidence was looking consistent and even more convincing support for a single species. The subtle morphological variation reported in 1991 seems to fall within the range expected for a very widespread holarctic species (by comparison with e.g. B. cryptarum), although this is not easy to quantify and is difficult to accept alone when using an integrative framework for recognising species.

I hope this helps.

(PS Neylon - I don't seem to have any unfulfilled requests on ResearchGate - please try again)

Publicado por paulwilliamsnhm hace alrededor de 1 año

"I'm not quite sure what kind of details you were expecting to see in the BBNA text. I could of course describe how I work as a taxonomist e.g. the hours of examining bees down the microscope looking at the subtleties of exoskeleton sculpturing and the many iterations of genetic tree building. Would a barcode tree showing the two taxa together with no difference between them help?" If papers are going to make statements like "Details on the justifications for these changes can be found in Williams et al. (2014)", then yeah, that's exactly the kind of details I would hope to find.

I didn't write this because I'm convinced that ashtoni and bohemicus are separate (I'm obviously not), I wrote this because It's annoying when papers tell me something authoritatively, but when I check their sources, I'm not seeing anything. Working on iNat: something like 3 or 4 times, someone had disagreed with an ashtoni ID by putting a bohemicus ID sending the observation out of the spotlight Subgenus limbo. In every case, they had referred to COSEWIC 2014. Which I feel does not properly show support for that change. Yes, it does point to papers that strongly indicate it, but not that show it.

But is it really too much to ask that when authors tell me where I can find extra details, that I actually find extra details there? To speak facetiously: these papers say "they're merged, Williams did tests, read more about it here" and I go there and all it says is: "yep".

While I fully acknowledge that I'd still have to take the work on faith (barcodes are quite a bit beyond me, and I've only seen a small handful of ashtoni specimens), I still want to at least see the work. Papers showing the work and the evidence for other splits and lumps are out there https://www.tandfonline.com/doi/abs/10.1080/00222933.2021.1900444
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0207080
https://academic.oup.com/isd/article/5/2/5/6239767?login=false
https://www.researchgate.net/publication/338624490_Substantial_genetic_divergence_and_lack_of_recent_gene_flow_support_cryptic_speciation_in_a_colour_polymorphic_bumble_bee_Bombus_bifarius_species_complex

Some while back, I was asking around for details regarding which one should be used. It was suggested a couple times that this change is from unpublished data. And people could only point me to the BBNA guide. If tomorrow, you published a 20 page formally synonymizing these two, then that would be what I'd reference when people asked for details regarding the change, and I would still criticize the other papers.

I sent you a DM on here with my email (I don't have yours regrettably). I am looking forward to reading that.

Publicado por neylon hace alrededor de 1 año

Sorry, I just saw you responded while I was typing, but I have to go to work. I'll read later. Thanks.

Publicado por neylon hace alrededor de 1 año

I'd suggest that publications are often considered to include their supplementary data and related documents. In this case it seems that some of the data is on BOLD. The links I added above include COI records for the species including some labelled as by Williams, so there is some information that can be accessed.

Publicado por bdagley hace alrededor de 1 año

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