Does anyone know why butterflies have their own taxonomical category and moths don’t? (By Lepidopterists, not by iNat)
Thanks
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Current taxonomy uses an approach called cladistics, where organisms are classified based on how closely related they are, and morphology and genetics are only used to discern this family tree. In cladistics, only groups that include an ancestor and all its descendants are considered valid (monophyletic groups). For example, if I were to make a clade out of my family and I put me and my cousin in it, I would have to put all of the other cousins from the same grandparents, I cannot leave some out, or it wouldn’t be valid.
Applied to lepidoptera, butterflies are all part of the same group, and their last common ancestor doesn’t have any other descendants. However, there are many different groups of moths that are as related to each other as they are to butterflies, meaning that if you make one big group that includes them all, butterflies would also be included there, as they come from the same ancestor. And of course, that group already exists, it’s called lepidoptera.
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Nowadays we use phylogenetic taxonomy. Without going too in depth it’s based upon our best current understanding of evolutionary history. Because of this, taxonomic groups within a phylogenetic taxonomy must be monophyla. That means that all species descended from the root species of that taxon must be in that taxon.
Butterflies (encircled in red) are such a group but moths are not. Moths are defined as basically “everything in lepidoptera except for butterflies”, which is shown by the cladogram below to be not a monophylum unless it also includes butterflies.
(Cladogram source: Wikipedia)
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It seems it is because butterflies are a monophyletic group, but moths are not. Essentially, to my understanding, Lepidoptera has many subgroups: Moth group 1, moth group 2, moth group 3, etc etc, and butterflies. As a result, the label “moth” is relatively unhelpful, as it would reference many loosely related lepidopteran groups, whereas “butterfly” is only one lepidopteran group.
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All butterflies are moths, but not all moths are butterflies.
Kind of like squares and quadrilaterals.
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Thanks to everyone who answered so far.
So even though I can look at a Lepidopteron and say, “Oh, that’s obviously a moth” or “Oh, for sure that’s a butterfly,” the assumption that all things evolved forms a scientific framework that negates my intuitive knowledge of moths & butterflies?
Are there other taxa that elicit that same response in anyone?
Just curious.
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Birds of prey are all messed up now.
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I mean on the one hand this makes complete sense, on the other hand we are on a webpage that has “Chromista” in its “taxonomic tree”, so making a taxon for “moths” wouldn’t be the worst thing to ever happen here :)
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All of them, LOL.
Coming from the humanities, there are a ton of linguistic and conceptual categories that are useful to us in communicative, cultural, or practical contexts that don’t line up with any sort of taxonomic category. Algae is probably the one that frustrates me the most…so far :)
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Everyday popular categories don’t necessarily correspond with taxonomic categories, and it is not unusual for such categories to have fuzzy boundaries and overlap in non-systematic ways instead of forming strict hierarchies (e.g., see discussions about what makes something a “sandwich” rather than some other kind of culinary item involving bread and filling).
Since most butterflies are diurnal, I imagine they are a relevant experiential category for humans who are visual creatures with poor night vision that are also usually active during the daytime, whereas most other lepidopterans are largely nocturnal.
This is also linguistically variable – not all languages differentiate butterflies and moths in precisely the same way as in English.
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yes, but only because month and butterfly as morphological concepts have nothing in common with how stuff evolved, but more of a common adaptation of agroup of animals to lifestyle/environment. moth is not a group, but a body plan.
In lepidopterans; it is quite obvious that the moth body plan evolved much earlier, and has many different iterations but still all firmly moth-like. However, someday, one group of moths evolved to live by day, and turned into butterflies; so butterflies are actually sort of day moths. true butterflies are not the only day moths though; it happen multiple times, its just tha true butterflies too the adaptations to day life the furtherst. And when comparing the day-adapted lepidoperans and night adapted lepidopterans, it becomes very obvious that what we morphologically categorise as moths and butterfly are just two ways of the same group of species adapt to two different lifes styles; moth-like at night, and butterfliy-like at night. Moth like is ancestral, and butterfliy like evolved many times; but its the most prominent in true butterlies.
Another group like that is bony fish; all land vertebrates (Tetrapods) , from amphibians to mammals) are actually bony fish, we are technicly all meat-finned fish - Sarcopterigyians* (today only Coealacanths and lungfish are clearly fish-shaped in that group, but we have an abundant fossil record of fishy members of our clade). IF we want to take Tetrapods out of bony fish, we need to take all those of our clearly fish-shaped ancestors out of fish also.
*the other group of bony fish is Actinopterygii (ray-finned fish). the two groups most obviously diiffer in fin structure of paired fins, ray finned have a very small meaty lobe, and most of the fin is a structure supported by fin rays (very clerly seen in some fish , eg. Betta fish). Sarcopterygians always have a big and prominent meat lobe in their fins (in tetrapods, all of it), although the ancestory still have fin ray, these are not as prominent (the only good example living today is the coelacanth)
Also ta “tree” is not a group of plants, but just a body plan. it evolved probably more than a hundred times +/- independently in various plant groups.
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Yeah. I still find it hard to come to grips with the fact that a falcon is more closely related to a parrot than to a buzzard.
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Good point, I had forgotten that about English & Leps!
Kind of like the Model T evolved into the Mustang, which is often driven at night by “cruisers.” Different body plans, different market, all cars. Which crawled out of the primordial ooze of the Midwest for our enjoyment. (I’m from the Midwest, no offense intended).
As was mentioned above, it’s just a language issue. English gives “butterfly” and “moth” their own words, despite a butterfly being just a specialized moth. Not every language breaks the Lepidoptera up this way though. For example, here’s the Spanish language Wikipedia on Lepidoptera:
https://es.m.wikipedia.org/wiki/Lepidoptera
It says they’re known as “mariposas”, some of which are diurnal and some of which are nocturnal (“mariposas nocturnas”). You won’t find a page specifically for “moths” in the English sense on the Spanish wiki, because it’s a concept that only exists if you speak English. Their page for Saturniids (pavones) calls them “mariposas”, which is usually translated into English as “butterflies”, despite Saturniids not being “butterflies” in the English sense. Another page for most other Leps calls those “polillas”, which is sometimes given as a Spanish word for “moths”, but isn’t quite analogous to English usage of “moth”.
It would be like if a language had one word for “bird” and another word for “duck”, but “bird” specifically excluded “duck” in that language. They might say “why don’t you have a taxon for ‘all-birds-not-including-ducks-because-ducks-aren’t-birds-in-my-language’?”
“Moth” exists as a concept in the English language, but as a taxonomic grouping it isn’t a thing. We just culturally have developed a term for “all the Lepidoptera that aren’t Papilionoidea”. Plenty of “moths” are closer related to “butterflies” than they are to other “moths” though. Language that predates the 1800s and actual evolutionary relationships discovered in the past 200 years sometimes happen to match up, but very often they don’t.
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So even though I can look at a Lepidopteron and say, “Oh, that’s obviously a moth” or “Oh, for sure that’s a butterfly,”
I think this has to do with what we’re used to. We all know what butterflies are, and we’ve somehow agreed to call all other Lepidoptera that are not butterflies, ‘moths’. So when you see one, it’s easy for your mind to make a distinction between these two groups. But if you’d really look at all different Lepidoptera families with an unbiased mind, you’d see that many moth families are actually very different from each other, in shape, color and behavior. Some you would even intuitively call ‘butterflies’, like many species from the Uraniidae family: https://www.inaturalist.org/observations?taxon_id=123027&view=species These really aren’t swallowtail butterflies, but moths!
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So why does iNat have a taxon for dicots, when modern taxonomy splits flowering plants into monocots, eudicots, magnoliids, and some other clades?
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Similar situation for bees and wasps. Bees are effectively a subcategory of wasps, some insects commonly called wasps are more closely related to bees than to some other insects commonly called wasps.
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Just to add that in Portuguese “mariposas” is moths and “borboletas” is butterflies.
In French we also have “papillon” and “papillon de nuit”.
Anyway I guess many other languages might have some situations like this.
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When the taxonomy of flowering plants was created on iNaturalist, plants were assigned to only monocots or dicots. Following the growth of the site to its current state, we are told it is no longer technologically possible to split taxa with so many associated identifications as “Dicots.”