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 mahenr...@gmail.com 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 < alcard...@gmail.com > 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: alcard...@gmail.com , andrea.card...@unimore.it
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
