A developmental perspective on the evolution of sexual size dimorphism of a moth

Abstract

Males and females of almost all organisms exhibit sexual differences in body size, a phenomenon called sexual size dimorphism (SSD). How the sexes evolve to be different sizes, despite sharing the same genes that control growth and development, and hence a common genetic architecture, has remained elusive. Here, we show that the genetic architecture (heritabilities and genetic correlations) of the physiological mechanism that regulates size during the last stage of larval development of a moth, differs between the sexes, and thus probably facilitates, rather than hinders, the evolution of SSD. We further show that the endocrine system plays a critical role in generating SSD. Our results demonstrate that knowledge of the genetic architecture underlying the physiological process during development that ultimately produces SSD in adults can elucidate how males and females of organisms evolve to be of different sizes.

Sex-Specific Weight Loss Mediates Sexual Size Dimorphism in Drosophila melanogaster

“…There is a paucity of data concerning the patterns of growth that generate SSD in other insects [6], [21]–[23]. Perhaps, the best study has been in the tobacco hornworm, Manduca sexta , where critical size and the duration of the TGP (called the ICG in M. sexta ) are important mechanisms contributing to SSD at the cessation of larval growth [21].…”

“…Perhaps, the best study has been in the tobacco hornworm, Manduca sexta , where critical size and the duration of the TGP (called the ICG in M. sexta ) are important mechanisms contributing to SSD at the cessation of larval growth [21]. Additional studies indicate that SSD in other Lepidopterans accumulates during development primarily due to females adding more instars than males [24].…”

Male Bias in Distributions of Additive Genetic, Residual, and Phenotypic Variances of Shared Traits

“…Of the 21 studies that statistically tested for male and female differences in heritabilities, 12 found significant differences in a subset of the traits examined (Mousseau and Roff 1989;Wilcockson et al 1995;Ashman 1999Ashman , 2003Mignon-Grasteau 1999;Jensen et al 2003;Rolff et al 2005;Ng et al 2006;Fedorka et al 2007;Zillikens et al 2008;Gershman et al 2010;Stillwell and Davidowitz 2010).…”

Evolutionary view on sexual dimorphism and shape variation in Iranian populations of Hypera postica (Coleoptera: Curculionidae)

“…Thus, finding such a character allows more convenient sex determination. On the other hand, the evolutionary explanation of sexual dimorphism in different taxa and the effect of sexual selection in the evolutionary progress are still ambiguous (Ridley 2003;Stillwell and Davidowitz 2010). Understanding the morphological variation of homologous characters between sexes would reveal the direction of selective pressures and let create hypotheses about it (Tatsuta et al 2004).…”