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Gradual vs. Incomplete Metamorphosis

It was my understanding that tree crickets undergo Incomplete Metamorphosis; however, this website indicates Orthopterans undergo Gradual Metamorphosis:

http://www.uky.edu/Ag/Entomology/ythfacts/4h/unit2/metavari.htm


Is the Subfamily of Oecanthinae the only Orthopteran that undergoes Incomplete instead of Gradual metamorphosis? (Are they the only Orthopteran that does not have ocelli?)

Am I too late?
I was going to add something yesterday and look all what happened since. This issue has been in my mind for a while.

According to the Encyclopedia of Insects (Resh, Vincent & Ring Cardé. 2003) article on Metamorphosis by Frederick Stehr (pages 707-708) The most used terms for types of metamorphosis are:
Anamorphosis (which occurs in Protura)
Ametabolous (other Apterigota)
Hemimetabolous (it includes gradual, incomplete, direct, paurometabolous)
Holometabolous (complete or indirect)

Simple metamorphosis is a broad term that includes everything other than holometabolous.
And of course he mentions special types and some intermediate types, such as Aleyrodidae and Thysanoptera that fall in between hemi and holometabolous.

Is it getting clearer now? I doubt it, but it looks like using the terms simple metamorphosis and complete or holometabolus is pretty safe.

This encyclopedia is a very good book and I have to figure out how to add it to the guide, or else, somebody please go ahead and do it. Info here
Update. It is here

Wow...this sure opened up a very confusing can of worms
Now I REALLY don't know what to put for Orthoptera and Oecanthinae.
My 6th edition of Borror, Triplehorn and Johnson have 3 terms under simple metamorphosis:
Ametabolous (adults and young look the same)
Paurametabolous (gradual--winged adults/nymphs no wings but look similar)
Hemimetabolous (incomplete -- aquatic nymphs / look different than adults)

These definitions are different from what is posted below. Is there an ultimate source?

 
Simple metamorphosis
I generally don't that term at all in my studies of insects. It's too confusing to use that term for those three types of lifecycles. I just use the specific four terms I learned while studying entomology at UW-Madison. In fact the Borror, Triplehorn and Johnson is the text book used in the introductory course at UW-Madison. It really depends on the individual's choice of usage in their own studies. For Orthoptera in general and Oecanthinae specifically, I recognize their lifecycle as being Paurometabolous, based on my educational experiences at UW-Madison.

 
It seems logical to me
to have one term that refers to all the insects that have a resting (pupal) stage, and another for those that do not. I agree that paurometabolous is more precise, but I think there is value in making the broader distinction on a guide page, for the general public who won't know what to make of the more precise term. It isn't incorrect to use the term simple metamorphosis, just not as specific, perhaps. The best option might be to say cricket metamorphosis is "simple, and specifically paurometabolous," or something to that effect.

 
defining terms
Perhaps instead of using those technical terms like paurometabolous, maybe if we use in the context like "simple, specifically gradual metamorphosis". I think we'll be able to convey the information a lot better. They will have some idea how the insect develops. I don't know if there is a page on the site that defines these types of lifecycles for the general public to understand as they access the information on the internet.

 
Glossary
here, but not in a very intuitive place, in my opinion... I wonder how many people find it on their own (I sure didn't).

 
If I didn't find the informat
If I didn't find the information, I would hazzard a guess that many others didn't find it at all. I was going through the guide to see how they used those terms. For the most part, I see them using both lay and technical terms to describe the lifecycle. I found one in particular in the Hopper and kin guide I think in my opinion needs to be re-evaluated:

"Auchenorrhyncha and Sternorrhyncha usually have three life-stages: egg, nymph, and adult - and some have prepupal and pupal stages. Some groups are ovoviviparous (eggs hatch inside female, and young are born live).

Heteroptera have gradual or incomplete metamorphosis (no pupa stage); juveniles (nymphs) resemble adults except they usually have reduced wings and are incapable of flight."

I don't know of any "True Bugs" aka Heteroptera having an incomplete metamorphosis. Cicadas would come to mind but I believe they belong to a different group and they have more of an incomplete metamorphosis, even though their immature is still called a nymph. One can get really exhausted over all the technicalities with these odd ball groups.

 
Placement of glossary entry for metamorphosis
Well, I don't see where the glossary entry for metamorphosis could go, other than in the Glossary under "M". That is about as intuitive as it can be, given the current structure of the guide and glossary. (In the future, there will perhaps be a separate tab for Glossary across the top--that would certainly be more intuitive.)
The terms ametabolous, hemimetabolous, paurometabolous, and holometabolous are also present in the glossary, with brief explanations and links back to the main entry for metamorphosis. I did not do separate entries for "simple metamorphosis", "complete metamorphosis" and the like because I figured people would be able to look under metamorphosis, but perhaps that is a good idea. Any editor can go in and add those entries.

It is a big editorial job to install hyperlinks in every guide page where metamorphosis is mentioned. I have done a few, but any editor is welcome to go into guide pages and insert hyperlinks that look like this:
[url=node/view/112362]metamorphosis[/url]
You can do a find on the word "metamorphosis", restrict it to guide pages, and right-click to edit that page in a new window--that is the quickest thing.

It would be great if the process to generate the hyperlinks could be automated, but I don't see this happening soon.

This is a good discussion--I put a link to it in the metamorphosis under "See also".

Certainly another thing to consider is that somebody could write an article on metamorphosis, and we could link to it from the glossary entry.

 
Placement
Yes, I was referring to the placement of the glossary itself. A glossary tab someday would be a great addition.

 
I don't think there's
disagreement here, just slightly different explanations. It would be correct to say all grasshoppers and crickets have simple metamorphosis or are paurometabolous. The distinction between the latter and hemimetabolous still seems subjective and arbitrary to me... I wonder which category a cicada falls into? They seem to do the same thing as dragonflies (immatures don't "look like" adults, to my eye), but happen to be terrestrial. Somehow I suspect they're considered paurometabolous though.

The main confusion is people are using "incomplete" to mean different things, but clearly some sources say that is a general term, equivalent to "simple."

Gradual, simple, incomplete
They are listed as equivalent terms here...

 
4 types of Metamorphosis
There are 4 types of metamorphosis in the insect world. They are:

Ametabolous - no lifecyle - eg. Silverfish
Paurometabolous - incomplete lifecycle - eg. Cricket
Hemimetabolous - gradual lifecycle - eg. Dragonfly
Holometabolous - complete lifecycle - eg. Beetle

I think of hemimetabolous always associated with aquatic insects. Paurometabolous are for terrestrial insects like grasshoppers and true bugs. These two types of metamorphosis are often confusing as to which group exhibit the type of development.

 
Can you explain
the difference in process between what happens with a grasshopper and what happens with a dragonfly? Apart from the fact that a grasshopper nymph looks more like an adult than a dragonfly naiad does? The aquatic-terrestrial distinction seems arbitrary. I'm not challenging what you're saying, but just trying to understand.

 
Aquatic insect orders like dr
Aquatic insect orders like dragonflies and damselflies have naiads that look nothing like the adult stages. The term incomplete metamorphosis is used to distinguish that notion in which the naiad is different. The adult emerges from the exuvia much like a butterfly emerging from a chrysalis, fully winged and requiring time to expand and dry out their wings. It is rather generalized, since there are other aquatic insects like some neuopterans undergoing a complete lifecycle.

The gradual metamorphosis illustrates the gradual development of wings in the nymphs as it matures into adulthood. Secondly, for paurometabolous insects this is where nymphs and adults both live in similar habitat situations. Hemimatabolous insects is where you'll find the naiads living in completely different habitat situations compared to the adults. That's the best idea I can come up at this time, perhap others can chime in to further explain.

A further note, since I can't edit the earlier post: I have mixed up the lay term for both Paurometabolous and Hemimetablous lifecycle. Paurometaboulous is supposed to be gradual whereas Hemimatabolous is supposed incomplete.

 
Perhaps
we should use the terms "hemimetabolous" which is the incomplete styles (egg, nymph, adult), Holometabolous, for complete, (egg, larva, pupa, adult) and in the case of things that actually change forms during larval state, like the scales pointed out below, I believe the term is hypermetabolous. I've never liked using the phrases incomplete and complete, as it makes it sound to the beginner like something is wrong from one to the other. just my 2 pennies.

 
Just to play devil's advocate...
the terms you prefer have the same problems, for a beginner who is paying attention to the etymology. "hemi" = half; "holo" = whole. Sounds like one is less than the other. I think that's fine though (with both sets of terms), because insects that are holometabolous / have complete metamorphosis are going through a more dramatic transformation, are they not? Ignoring the weird things that scales, whiteflies, etc. do, of course, but they don't seem to fit very nicey into these categories any way you slice them.

Thanks Beatriz, Chuck and Hannah....
...yikes. I still have SOOO much to learn. So Gradual Metamorphosis it is. I think I need to do some editing somewhere :( Including the Info page under Order of Orthoptera - Crickets, Grasshoppers and Katydids [which may be where I started out with my incorrect understanding:) ]

Ah, terminology!
I always thought that gradual was a subset of incomplete metamorphosis.
Borror lists: 1) simple metamorphosis and 2) complete metamorphosis to which he adds intermediate types of metamorphosis adding that "not all insects have a type of metamorphosis that can be readily classified as simple or complete."
If we followed this scheme Odonata, Orthoptera, Hemiptera, etc. (everything but Endopterigota) have simple metamorphosis.
Maybe somebody can enlighten us on this.

 
My favorite example:
Whiteflies, which start out as "crawlers" with legs, then attach to a host, lose their legs, and become like scale insects- all while technically still nymphs- and finally emerging as a legged, winged adult:



"Not ... a type of metamorphosis that can be readily classified as simple or complete", indeed.

 
I think
This is considered a hypermetabolous insect, correct?

 
Whiteflies
After reading up on whiteflies, I do read there is a pupa stage during their development, according to Borror, Triplehorn and Johnson. By defination, it does fit within the parameters of being hypermetamorphic.

All have gradual metamorphosis, according to this site
I'm not an expert on these categories, but I checked the Glossary entry here, and all orthopterans are listed as having gradual metamorphosis, whereas incomplete metamorphosis describes insects with aquatic larvae. I wonder if you're thinking of the distinction of "simple" versus "complete" metamorphosis - it is somewhat confusing (to me, at least) that "incomplete" is not the only alternative to "complete".

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