Damien I should also say that given the range of size variation you are suggesting (i.e. where there is no overlap in size distributions between the focal species for instance ) then I would not use the approach I suggested. You would be in a position of extrapolating the shape ~ size relationship likely too far away from where you would be comfortable with the prediction (and uncertainty in the prediction).
Also if your intraspecific shape ~ size models are for ontogenetic allometries I am even more skittish (because ontogenetic allometries so often have non-linear relationships). So it may be that what I advocated is not useful for your questions. On Tue, 14 Jul 2020 at 21:32, Damien Esquerre <[email protected]> wrote: > Dear all, > thanks for the excellent feedback. I need to maybe clarify some things: > > I am definitely aware and agree that interspecies comparisons need to be > done in a phylogenetic context. However, when you have multiple individuals > per species, and are comparing intraspecific vectors such as allometric > slopes between species (I know it sounds contradictory but hopefully you > know what I mean) I am not aware of any method that can incorporate > phylogenetic information (these usually rely on species means, or one value > per species). We sort of explored a bit of that issue in the attached > paper. I guess I can think of ways around it, like including 'clade' as a > factor in the model, but that doesn't fully account for the relationships > between species. I think Dean and Mike have been working on this? > > I like Ian's suggestion of using species means at a comparable size. > However, that wouldn't work when we are talking about species with orders > of magnitude in size difference. > > Something I can think of, even if ontogenetic trajectories are different > between species, one could compute the evolutionary allometric trajectory > of the mean adult shape of a group of species, and then extract the > residuals from that regression. I guess there could be many arguments > against doing this if those species have different ontogenetic > trajectories, but would love to open a discussion about this. > > Another option is just not performing any allometric corrections and > accept there will be a confounded allometric component to variation with > the evolutionary (interspecific variation). > > In the end, what would you do if you wanted to detect mode of evolution, > convergence and or adaptation (effect of environment) in a clade that > displays heterogeneous allometric slopes? In particular, when you dont have > comprehensive ontogenetic series and that is not the focus of your question. > > This is something I've been thinking about for years, and it fascinates > me, but have never arrived at a satisfactory answer. > > Thanks again! > Damien > > On Wed, Jul 15, 2020 at 6:04 AM Mauro Cavalcanti <[email protected]> > wrote: > >> Dear Hugo, >> >> >shape of one particular species. Now regarding the Ian example in >> Drosophila, I tested allometry into 60 species across the genus and there >> is definitely a >pattern (indeed a beautiful one across the genus looking >> into the different clades) but looking into one particular group of species >> the "size" is indeed a very >> >> Have you already published this work? If so, could you please provide a >> reference? It looks truly great. >> >> With best wishes, >> >> Em ter., 14 de jul. de 2020 às 16:57, Hugo Benítez < >> [email protected]> escreveu: >> >>> Fantastic line of discussion >>> >>> I'm absolutely agree with Joe, when there is not a Phylogenetic context >>> maybe the allometric correction would not have very much sense, because we >>> are looking into only one generation so we really don't know very well if >>> the shape we are looking for is product of environmental condition (that >>> can be connected with plenty of variables like nutrition, stress, etc...) >>> now as you asked there is multiple group of species so definitely in your >>> idea there is some "historic factor" that provide the shape of one >>> particular species. Now regarding the Ian example in Drosophila, I tested >>> allometry into 60 species across the genus and there is definitely a >>> pattern (indeed a beautiful one across the genus looking into the different >>> clades) but looking into one particular group of species the "size" is >>> indeed a very good trait to explain differences (like species from island, >>> marsh or the typical cosmopolitan) cosmopolitan Drosophila have the simple >>> small wing (very small). On the other hand, where maybe "makes sense" is >>> in one single species after doing some quantitative genetics experiments >>> and controlling the factors that could influence the size depending on your >>> question... But I think if there is a simple species in the game the >>> factors in one generation are indeed just the real biological meaning of >>> your differences and I dont think a correction will have a very biological >>> meaning... Now of course could be some exception to the rule and a >>> Biogeographical question like bergmann rule, or another rule like that >>> where the relationship is directly related to size maybe a correction could >>> be ok to see how big there are the differences when the factor is >>> included... >>> >>> I would love to see more replies, nice topic to discuss Damien >>> >>> Best >>> Hugo Benítez >>> >>> >>> El mar., 14 jul. 2020 a las 14:55, Damien Esquerre (< >>> [email protected]>) escribió: >>> >>>> Dear morpho community, >>>> I have a philosophical question on size correction that should start an >>>> interesting discussion. >>>> When we are interested in seeing the effects of species or >>>> environmental variables for example, on shape, people often first remove >>>> allometric variation by computing the residuals of a shape ` size >>>> regression. This of course, doesn't make sense if there are heterogeneous >>>> slopes and species have different allometric trajectories (i.e. if the >>>> species*size term is significant). >>>> What do you think would be the most appropriate way to deal with this >>>> situation then, if you are interested in environmental effects on shape? >>>> Best regards, >>>> Damien Esquerré >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Morphmet" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/morphmet2/CAJiv7Cw0S2A%3D-kpEmknt-tUp92Vjy0hkiF%3DVF6C77NsFECP%2BMw%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/morphmet2/CAJiv7Cw0S2A%3D-kpEmknt-tUp92Vjy0hkiF%3DVF6C77NsFECP%2BMw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >>> >>> -- >>> >>> *Dr. Hugo A. Benítez* >>> Profesor Asociado >>> Centro de Investigación de Estudios Avanzados del Maule >>> Universidad Católica del Maule >>> >>> Research Associate, University of Cambridge Museum of Zoology >>> External Researcher Faculty of Agriculture, University of Zagreb >>> >>> Lab website: http://www.morphoshape.com <http://www.hugoabenitez.com> >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Morphmet" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/morphmet2/CACTC4WqeQiyyLW0gGy%3Ds8jr%3DM0pXAJmuEqXGKUCAaxs3%3DOa%2BmA%40mail.gmail.com >>> <https://groups.google.com/d/msgid/morphmet2/CACTC4WqeQiyyLW0gGy%3Ds8jr%3DM0pXAJmuEqXGKUCAaxs3%3DOa%2BmA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> >> >> -- >> Dr. Mauro J. Cavalcanti >> E-mail: [email protected] >> Web: http://sites.google.com/site/maurobio >> "Life is complex. It consists of real and imaginary parts." >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Morphmet" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/morphmet2/CAC1JhZYNJdDWqfrsGXGa%2Be0YX8oA5CjoLBTXa67wHuGHaSqJbQ%40mail.gmail.com >> <https://groups.google.com/d/msgid/morphmet2/CAC1JhZYNJdDWqfrsGXGa%2Be0YX8oA5CjoLBTXa67wHuGHaSqJbQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> > -- > You received this message because you are subscribed to the Google Groups > "Morphmet" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/morphmet2/CAJiv7CxV96Zj%2B6Sq793eq%3DB-5EoJ4FbbbOW5K1DsS3ENwYCuDw%40mail.gmail.com > <https://groups.google.com/d/msgid/morphmet2/CAJiv7CxV96Zj%2B6Sq793eq%3DB-5EoJ4FbbbOW5K1DsS3ENwYCuDw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- Ian Dworkin Department of Biology McMaster University Office phone 905 525 9140 ext. 21775 Lab phone 905 525 9140 ext. 20076 [email protected] dworkinlab.github.io -- You received this message because you are subscribed to the Google Groups "Morphmet" group. 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