Dear All, I am not aware of published studies using morphometric geometrics to test the variance difference between males and females. The only studies I know use linear morphometry to test these differences (referencesare below). Trait variance depends on what sort of trait you are testing. Sexually dimorphic traits tend to have more variance than naturally selected traits (Bonduriansky, 2007; Fairbairn, 2005, references below). By extension, it depends on which trait you are looking at: if males are being selected (e.g. ornaments, weapons), you would expect more variance in males than females; if females are being selected (e.g. abdomen size for carrying eggs) you would expect more variance in females. This occurs because sexually selected traits usually are condition-dependent - individuals with a good conditions (e.g. good nutrition) can develop more costly traits that increase their fitness. Meanwhile, low condition individuals cannot afford to develop a costly trait, and thus will have a smaller than expected trait. Consequently, this increases variance in that trait for that sex. If the trait is naturally selected (e.g. walking legs), on the other hand, you could expected equal variances between the sexes - both sexes need the best perfoming traits in order to survive. However, biology seldom is straightforward, so there may be instances where variance patterns are not so clear (e.g. regions with low resource availability). I added a non-exhaustive list of references on condition-dependent traits below. Cheers, Alexandre Bonduriansky, R. (2007). Sexual selection and allometry: a critical reappraisal of the evidence and ideas. Evolution , 61 (4), 838-849. Fairbairn, D. J. (2005). Allometry for sexual size dimorphism: testing two hypotheses for Rensch’s rule in the water strider Aquarius remigis. The American Naturalist , 166 (S4), S69-S84. Bonduriansky, R. (2007). The evolution of condition‐dependent sexual dimorphism. The American Naturalist , 169 (1), 9-19. Cothran, R. D., & Jeyasingh, P. D. (2010). Condition dependence of a sexually selected trait in a crustacean species complex: importance of the ecological context. Evolution , 64 (9), 2535-2546. Bonneaud, C., Marnocha, E., Herrel, A., Vanhooydonck, B., Irschick, D. J., & Smith, T. B. (2015). Developmental plasticity affects sexual size dimorphism in an anole lizard. Functional Ecology . Johns, A., Gotoh, H., McCullough, E. L., Emlen, D. J., & Lavine, L. C. (2014). Heightened condition-dependent growth of sexually selected weapons in the rhinoceros beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae). Integrative and comparative biology , icu041. De Lisle, S. P., & Rowe, L. (2014). Interactive effects of competition and social environment on the expression of sexual dimorphism. Journal of evolutionary biology , 27 (6), 1069-1077. House, C. M., Jensen, K., Rapkin, J., Lane, S., Okada, K., Hosken, D. J., & Hunt, J. (2015). Macronutrient balance mediates the growth of sexually selected weapons but not genitalia in male broad‐horned beetles. Functional Ecology .
On Thu, Aug 25, 2016 5:28 AM, mahendiran mylswamy [email protected] wrote: Dear Dr. Andrea I am equally keen to see papers on the same topic which you suggested, so please forward those pdf (if you receive form morphomet community) that discusses differences in the variance of a given trait than the differences in mean alone. Again, thanks in advance:) Cheers Mahendiran On Wed, Aug 24, 2016 at 9:27 PM, andrea cardini < [email protected] > wrote: Dear All, I am looking for papers comparing variance in morphometric and other phenotypic traits in females and males. I am not talking about mean differences as in most tests of sexual dimorphism. I am interested to see whether people have found similar variance in a given trait in the two sexes or they found that one sex tends to vary more than the other. Thanks a lot in advance for your suggestions (and pdfs, if available!). Cheers Andrea -- Dr. Andrea Cardini Researcher, Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi, 103 - 41125 Modena - Italy tel. 0039 059 2058472 Adjunct Associate Professor, School of Anatomy, Physiology and Human Biology, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia E-mail address: [email protected] , [email protected] WEBPAGE: https://sites.google.com/site/ alcardini/home/main FREE Yellow BOOK on Geometric Morphometrics: http://www.italian-journal-of- mammalogy.it/public/journals/3 /issue_241_complete_100.pdf -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- 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 morphmet+unsubscribe@morphomet rics.org . -- ****************************** ********* M Mahendiran, Ph D Scientist - Division of Wetland Ecology Salim Ali Center for Ornithology and Natural History (SACON) Anaikatti (PO), Coimbatore - 641108, TamilNadu, India Tel: 0422-2203100 (Ext. 122), 2203122 (Direct), Mob: 09787320901 Fax: 0422-2657088 www.sacon.in -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- 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] . Alexandre Varaschin Palaoro http://alexandrevpalaoro.weebly.com Núcleo de Estudos em Biodiversidade Aquática - Universidade Federal de Santa Maria -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- 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].
