If the character is stable, there can be different optimums for both sexes. Selection operates on both sexes at the same time; therefore it is necessary to explain not only why one of the sexes is relatively bigger, but also why the other sex is smaller.Székely T, Freckleton R. P., Reynolds J. D. (2004) Sexual selection explains Rensch's rule of size dimorphism in shorebirds. PNAS, 101, N. 33, p. 12224–12227. If owls are still evolving toward smaller bodies and longer wing chords, according to V. Geodakyan's Evolutionary Theory of Sex, males should be more advanced on these characters. Males are viewed as an evolutionary vanguard of a population, and sexual dimorphism on the character, as an evolutionary "distance" between the sexes. "Phylogenetic rule of sexual dimorphism" states that if there exists a sexual dimorphism on any character, then the evolution of this trait goes from the female form toward the male one.Geodakyan V. A. (1985) Sexual dimorphism. In: Evolution and morphogenesis. (Mlikovsky J., Novak V. J. A., eds.), Academia, Praha, p. 467–477.
If the character is stable, there can be different optimums for both sexes. Selection operates on both sexes at the same time; therefore it is necessary to explain not only why one of the sexes is relatively bigger, but also why the other sex is smaller.Székely T, Freckleton R. P., Reynolds J. D. (2004) Sexual selection explains Rensch's rule of size dimorphism in shorebirds. PNAS, 101, N. 33, p. 12224–12227. If owls are still evolving toward smaller bodies and longer ,wing chords, according to V. Geodakyan's Evolutionary Theory of Sex, males should be more advanced on these characters. Males are viewed as an evolutionary vanguard of a population, and sexual dimorphism on the character, as an evolutionary "distance" between the sexes. "Phylogenetic rule of sexual dimorphism" states :that if there exists a sexual dimorphism on any character, then the evolution of this trait goes from the female form toward the male one.Geodakyan V. A. (1985) Sexual dimorphism. In: Evolution and morphogenesis. (Mlikovsky J., Novak V. J. A., eds.), Academia, Praha, p. 467–477.