Taxacom: Minimalist revision of Mesochorus
Lynn Raw
lynnrgraw at gmail.com
Thu Aug 31 02:38:06 CDT 2023
I know that pushing the identification and description of new species being necessary for the protection of biodiversity is being used as a tool to obtain funding but in reality it is far more important to protect the remaining diversity of habitats than to worry about individual species, perhaps to the detriment of other species.
On another tack, I saw a paper, unfortunately behind a paywall, where the authors looked at using barcodes as a tool in forensics. I presume this is because of the variability in human mitochondrial DNA see https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHuman_mitochondrial_DNA_haplogroup&data=05%7C01%7Ctaxacom%40lists.ku.edu%7C0863541a573a4c5b875c08dba9f53e98%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C638290643313211873%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000%7C%7C%7C&sdata=hssGvvi8zFJqViu2tK7RUuWJfY1fkEe91dG%2FuYjt%2FkY%3D&reserved=0
A search of the internet will provide a number of articles relating to the use of mtDNA in forensics for those who are interested.
While in many cases taxa are separated simply by presence or absence of one or more character states in the examined samples, there are also some that are based on the statistical analysis of meristic characters. Most papers that I have read that use DNA for taxonomy have sample sizes too small for statistical analysis. How do we know that these samples are actually representative of the species as a whole? There is also the problem of unknown convergence as well as occasional hybridization with a female of another species resulting in some members of a population having different mtDNA to the rest of the population. I think that there needs to be a lot more research into these aspects before we can have full confidence in the reality rather than just faith in the theory. I suspect that barcoding may eventually be shown to be much less reliable than is currently believed.
Just my thoughts that, while DNA barcodes might possibly be useful additional details in species descriptions, they should not be used as the sole diagnostic determinant.
Regards,
Lynn Raw
> On 31 Aug 2023, at 02.24, Richard Pyle via Taxacom <taxacom at lists.ku.edu> wrote:
>
> Again, I think this is a really great and constructive discussion! I limited myself in my previous post to "Commissioner-speak" with respect to the Codes, but the real crux of this discussion (as pointed out by others) is "good taxonomy" vs. "bad taxonomy". The point I wanted to make is that this discussion -- like almost everything else in life -- boils down to a cost/benefit decision. There are no "right" or "wrong" answers, but there can be "better" or "worse" answers depending on what the goal is. In this case, we have two competing goals:
>
> 1) Increase the pace of documenting biodiversity, so we aren't so handicapped in the race against biodiversity loss as we are if we keep describing new species at historical rates.
>
> 2) Avoid making matters worse by cluttering the world with ambiguous and superfluous scientific names that cause more harm in terms of future taxonomists dealing with a mess of names.
>
> The good news is that these are not mutually exclusive goals, and I think Jose's excellent post did a fantastic job of making that point. There are examples at both extremes (hyper-careful/robust taxonomy that yields 10 new species after 20 years of work at one end; and mass minimalist cranking out of names at the other), but the real trick here is threading the needle in such a way that we get the most benefit (#1) at the lowest cost (#2).
>
> Discussions like this are extremely helpful (to me, at least) for figuring out how to thread that needle. The ICZN Code is very limited in its role for promoting "good taxonomy", but that role is not zero. And it's one of the only actual "legal-ish" standards in biology, and thus has at least a small amount of influence over how taxonomists do their work.
>
> Aloha,
> Rich
>
> Richard L. Pyle, PhD
> Senior Curator of Ichthyology | Director of XCoRE
> Bernice Pauahi Bishop Museum
> 1525 Bernice Street, Honolulu, HI 96817-2704
> Office: (808) 848-4115; Fax: (808) 847-8252
> eMail: deepreef at bishopmuseum.org
> BishopMuseum.org
> Our Mission: Bishop Museum inspires our community and visitors through the exploration and celebration of the extraordinary history, culture, and environment of Hawaiʻi and the Pacific.
>
>> -----Original Message-----
>> From: Taxacom <taxacom-bounces at lists.ku.edu> On Behalf Of Neal Evenhuis
>> via Taxacom
>> Sent: Wednesday, August 30, 2023 10:44 AM
>> To: taxacom at lists.ku.edu
>> Subject: Re: Taxacom: Minimalist revision of Mesochorus
>>
>> Although I am an ICZN Commissioner, I am speaking here as a taxonomist
>> who has described more than 700 new species of flies, all based on
>> morphological characters (although I have used molecular ones to test
>> hypothetical species groups to tell me I was either spot on or whacko in my
>> hypotheses). To me, molecular characters are just another character set and
>> not the end unto themselves. As has been pointed out, barcodes do not
>> always = unique species and to use them without resort to morphological
>> characters is, in my opinion, sloppy taxonomy.
>>
>> I was trained in taxonomy in an age where we were curious biologists and
>> wanted to know not only the manifest of Spaceship Earth (yes, I’m from the
>> Bucky Fuller era), but how things worked. We went into the field; hand-
>> collected specimens, and watched our taxa live their lives and how they
>> nourished, parasitized, predated, courted, mated, etc. When I describe
>> species impaled on pins or floating in ETOH (thankfully I do not have to
>> prepare them on slides – except genitalia), I am always asking myself how
>> those species recognize each other in order to mate and have F1 generations.
>> If Sharkey et al. are on the right path, then maybe they have sensory devices
>> we have not found yet that can discern barcode sequences and those little
>> wasps can confidently say with a wink after they have found one of their kind
>> and the opposite sex -- “Whoowhee, baby! How YOU doin’ ACCGTCTAAGGT?”
>> I doubt it. Insects have other sensory devices to discern their own species. I
>> do not think males of Mesochorus in Guanacaste fly around humping
>> everything that looks similar in hopes of a successful mating (maybe they do
>> – do we know? That would be a step backward evolutionarily as wasteful
>> energy epxediture). Instead I’d wager they discern their own species either
>> visually or semiochemically. The former requires that each species is visually
>> different somehow. The latter may require other techniques that include
>> molecular - in hopes that what is used codes for those different
>> semiochemicals. Barcodes do not. Nor do they always account for normal
>> variation in a population of the same species.
>>
>> My hunch (having done taxonomy on tropical flies over the last 40+ years - in
>> habitats similar to the dry-but-tropical Guanacaste) is they use visual
>> characters. I am finding that some of the tropical flies I work with have
>> unique Wing Interference Patterns (WIPs) that are used in species
>> recognition. Males and females all have to rest and when they do and the
>> sunlight hits their wings, they show a distinct pattern that is receptive to like-
>> kind species. They sometimes vary geographically in the same species, but in
>> restricted geographical populations where many occur sympatrically, they
>> work well in differentiating otherwise cryptic species. There are other hard-
>> to-see morphological characters to differentiate (some internally), but the
>> WIPs cinch my hypotheses that the specimens are the same taxon and I
>> hypothesize THAT is the way they find each other. Do Mesochorus use WIPs
>> for species recognition? I don’t think Sharkey et al. ever tested that. And
>> maybe WIPs won’t work and are indeed too variable. Apparently they are in
>> other Hymenoptera like Figitidae. But rather than look for WIPs or other
>> morphological sets of characters that may solve that problem, Sharkey et al.
>> resorted to an expedient way of running sequences and putting names on
>> BINs and letting future workers sort out the mess. I’m not a fan of that as a
>> way to “solve” the taxonomic impediment – it just creates another
>> impediment for future workers.
>>
>> We all want to solve the taxonomic impediment by finding expedient ways of
>> naming all the undescribed species that are still out there (some of us are
>> doing it, others are armchair pundits only but rally others toward that goal).
>> But I would suggest not to fall back on the “easy way out” with the routine of
>> “barcode first and ask questions later” -- but instead ask yourself -- if I were a
>> [put taxon name here] how would I find a mate? and look for other
>> morphological character sets -- and use barcodes as just another character
>> set and not THE only one. I still am curious about biology and taxa and how
>> things work in real life. Unfortunately, DNA sequences do not tell me that.
>> Maybe we have lost the luxury of time to learn more about our taxa and have
>> lost sight of that while keeping our eyes on the prize of describing as many
>> things as fast as we can. I hope we taxonomists do not devolve into pipette
>> jockeys and number crunchers and lose the curiosity of how things work in
>> real life.
>>
>> Neal
>>
>> Neal L. Evenhuis
>> Senior Curator of Entomology
>> Bishop Museum
>> Honolulu, Hawaii 96817-2704, USA
>>
>> On Stardate 8/30/23, 9:49 AM, "Taxacom" <taxacom-bounces at lists.ku.edu>
>> wrote:
>>
>> I think one thing that seems to be missed in the discussion is that, despite
>> lacking a morphological diagnosis in words, the species presented in the
>> Mesochorus paper do provide a substantial amount of biological information
>> (identity of host parasitoid, caterpillar host of primary host parasitoid, host
>> plant, plant community in which it is found) plus multiple photos showing
>> the morphology, in addition to the barcodes and collection data. It could be
>> argued that this combination of information is actually more extensive than
>> the earlier descriptions in the group, and more useful to ecologists and other
>> biologists. This is not to say it is the perfect solution, nor is it the way I
>> typically work, but it is not quite so minimalist as it may be portrayed as
>> being.
>>
>> Jim Sent from my iPhone
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