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"phase" or "form" or "morph"?

As a non-entomologist, I have a question about the use of the word "phase" in reference to the two differently-colored females (yellow and black) of the Eastern Tiger Swallowtail butterfly. Why are these colors called "phases" rather than "forms" or "morphs"? "Phase" implies a temporary condition -- which is not the case with these butterflies' coloration. Wouldn't "form" or "morph" be more accurate? I've seen all three terms used on other Web sites, sometimes by the same author. Is a formal distinction normally made between these terms in entomology?

Morph, phase, color phase
It seems that all these terms are used in entomological papers and it seems that phase refers mostly to color phases, although it is also mentioned as solitary and gregarious phases of grasshoppers, etc.
A few examples of phase.
Iowa State U.: "Bean leaf beetle (red phase and yellow phase)"
University of Florida: "The color of adult lubbers varies throughout most of the insect's range. One phase is nearly entirely black with a few marks of yellowish tawny. The adults of this phase seem to resemble the nymph. However, the different phases are indeed the same species."
Encyclopedia of Entomology. Volume 3, page 1666. Grasshoppers and locusts pests of Africa; "... gregarious phase. . . solitary phase. . ."
And examples of morph:
Neotropical Entomology: "The southern green stink bug, Nezara viridula (L.) is known to be polymorphic, including 10 different color morphs which are derived from four basic types."
PubMed: ". . .an environmental factor involved in morph determination of the tropical beetle, Callosobruchus subinnotatus. Adults occur as relatively sedentary, highly fecund, 'normal' morphs or as an 'active' morph adapted to dispersal."

may imply a temporary condition in casual conversation or in other scientific contexts, but in zoology "color phases" do indeed refer to different (permanent) forms a given creature may take. For example, the Eastern Screech Owl commonly comes in two colors: the "red phase" and the "gray phase."

As indicated here, "the word "phase" does not mean that animals change between color phases over their lives."

This is getting interesting.
I have six bird guides. All but one (the older Peterson's) refer to the Eastern Screech Owl's color variations as morphs, not phases. ("Morph" would seem equally inappropriate until one realizes that "morph" is short for "morphology," not "morphing" or "metamorphosing.") I remain unconvinced that the term "phase" is not a historical grammatical error that just got repeated often enough that it stuck -- until the 1970s or so, when folks had the same realization I had and started using "morph" instead.

I just found an interesting article that address the subject (for birds, at least):

Phase, Morph, or Color Variations?

Apparently the issue is still controversial, but I can't find any other references.

Interesting indeed!
But since the term ("phase," meaning a genetically determined color variant) can still be found in many references (at least many of the older ones), I think it belongs in the glossary. It might be helpful to include some mention of the "controversy," though.

See my post below.
The professor implies the use of "phase" is not controversial, but simply incorrect.

Saw that after I posted. :)
I wouldn't presume to argue with the professor. However, as long as the term can still be found in many older references I would argue for it's inclusion in the glossary.

I don't disagree...
I agree it should be included in the glossary, perhaps with the addition of a caveat that it's considered obsolete, plus a "see morph" link (to a new "Morph" glossary entry).

But what should be done with all the individual species' Info pages that use the term "phase"? Assuming this terminology use is incorrect, is it realistic to ask authors to edit all existing pages?

None of the reference sites or reference books I've looked at indicate that this sense of the word "phase" is obsolete.

Please share a few...
... of the references you found and their years of publication. Did any of them use "morph" or "form" or discuss the distinction between those terms and "phase"? Interestingly, the only Internet reference cited by Troy Bartlett, the author of the original article that prompted this thread, uses the term "form" — not "phase" nor "morph" (see "Butterflies and Moths of North America"). I've sent an email to Troy asking him if he might offer his opinion (and perhaps explain why he chose to use "phase").

I find it hard to believe that the "debate" amongst ornithologists doesn't have a counterpart among entomologists. Perhaps only because bird watching has been so popular that lay people forced the issue among ornithologists (see A Naturalist's Way with Words) and no equivalent popular interest exists in the bug world (this site notwithstanding).

It might not be Troy
Troy just created the original guide page. There are several others who have edited the page and may be responsible for the wording in question. Any BugGuide editor has the capability of making such changes, and it's usually hard to tell who wrote what- guide pages should be considered a collective effort, like a Wikipedia page.

I wasn't aware of that (or had forgotten). Thanks for clarifying.

Got the email
I don't think the comments about "phases" were part of my original page. In fact, my original was probably nothing more than a stub (like most of the initial guide pages I generated programmatically). It was probably one of the subsequent contributors (my money is on cotinis) that added those comments.

Having read over most of the comments here, I would probably use "form" or "morph" for any future guide page comments I write. That seems to make more sense to me than "phase".

Thanks, and apologies...
for assuming you wrote the most recent incarnation.

I was using "reference" in the sense of a dictionary or encyclopedia. These two are the ones I looked at:
(Copyright Random House Inc. 2010)

Merriam-Webster's Collegiate Dictionary, 10th Ed. (1999).

Ah, OK. Thanks.
I'm hoping someone has a recent zoology or entomology textbook that might shed some light on current thinking in the field. (General dictionaries and encyclopedias don't always keep up to date with scientific trends, especially ones as nuanced as this.)

Is it actually obsolete?
I would be happier if we had an example specifically from entomology, since ornithologists and entomologists don't necessarily use all the same terminology.

I suspect the term "phase" is based in the idea of changes in populations rather in individuals: the phases are differences that don't change the nature of the species as a whole.

As for the term "morphs", the main problem is that carries an implication of variation in shape rather than color. The verb "to morph" is quite recent, and I don't think it's made its way into scientific terminology yet.

We should keep in mind, though, that language (including scientific terminology) doesn't always make sense just based on the origins of the words- the key is whether the term is valid in current use among entomologists (or, more specifically, lepidopterists?)

Here's yet another view
The author of the article, "A Naturalist's Way with Words," traces the history of ornithologists' use of "phase" vs "morph," finds both terms unsatisfactory, then proposes yet a third (invented) term, "chromer":

'The coinage "chromer" draws on the original distinctiveness of the Greek language as long-used in biological scholarship and does so while retaining the useful term "morph" but without resurrecting the confusing term "phase."'

I don't know if his etymological analysis is accurate or useful, but the chronology is the most thorough Web reference I can find on the historical use of phase/morph, at least for ornithology. I find it hard to believe that entomologists haven't had a similar debate. Surely there must be similar references in the entomological literature.

I don't know...
"Chromer" strikes me as a bit odd: the -er ending seems to be more informal/humorous, which clashes with the scientific context . It also seems to have another meaning having to do with drug abuse.

Another possible term is "chromomorph", which has been used in approximately our sense in at least one journal article referring to Lepidoptera.

Update: a more etymologically correct form would be "chromatomorph", which can be found in several articles online

I never liked that usage of the word phase for the reasons expressed above, but thought that it was necessary to add it to the glossary because of its frequent use. I am happy with this outcome, actually. I can add the caveat, create a glossary page for morph (it goes with polymorphism after all) and make corrections in those places where phase is used incorrectly. I will try to do that later on today. Afterward, let me know here or in the page improvements forum if there are still a few left.

That's a question
for those wiser and more experienced than I. :)

Let me know if you like the new entry I just added to the glossary.

Nice. My only suggestion is that it state whether the example is of sense 1 or sense 2.

Found something.
Here's a biology professor's view on the matter (at least as it pertains to birds):

“[...] Lay people (even some professionals) still use the out-dated word, "phase" to describe two color morphs that are distinct genetically. The reason, "phase" is inappropriate is that it implies that the description is something that will change over time, such as "going from one phase to another". Wheeler & Clark in their 1995 "A Photographic Guide to North American Raptors" define the words as follows: Phase: Term formerly used for color morph. Phase implies a temporary condition; color morphs are permanent. See "morph". Morph: Term used for recognizably different forms of a species, usually color related. Color morphs are dark, rufous, and light. See also "phase". I know of no professional avian biologist who uses phase when morph is the proper usage--at least in print. If you don't mind using canadian Goose instead of Canada Goose, then this difference might not be important to you. But if you would like to state things correctly from an accepted biological standpoint, perhaps these definitions might be of interest.”

Kent D. Hall, Ph.D.
Professor Emeritus of Biology
Dept. of Biology
UW-Stevens Point

Source: (2009)

"morph" = "form" = "variant" = "variety"
have been used interchangeably in the carabid literature in reference to structure and/or coloration. At least in my work I consider the first three words to be synonyms, but tend to avoid the ambiguous term "variety" which might have been intended/published as a provisional subspecies or infrasubspecies designation in many cases. Yes, "phase" implies something temporal as in the pale "teneral phase" of adult beetles. Terms like "aberrant", "abnormal", "deviant", "dwarf", and "giant" I reserve for certain rare individuals that stand out from the population norm.

See my post above.
(In other words, I'm not sure the case is closed :-) )

I like it.
Good addition, Beatriz!

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