Although, sexual variation is traditionally understood as being any difference exhibited between males and females, evolution has often resulted in the coexistence of alternative reproductive morphs within the sexes. Significant progress has been made in understanding within species coexistence of discrete male colour morphs, while female polymorphism is less understood. Typically, one of the female damselfly morphs is coloured like the male, while the other morphs are different. While one group of researchers argue that male-like females are functionally male mimics, others believe that males predominantly mate with the most common female morph in the population. Importantly, both field and experimental (using different insectaries with a range of densities and frequencies) studies support a relationship between population conditions (density, sex ratio, morph frequency) and morph-specific fitness correlates (i.e. survival, mating success). However, in order to explain the maintenance of female polymorphism, differences in morph-specific fitness should be encountered if fluctuations occur in population conditions. Unfortunately, only very limited information on spatial and temporal fluctuations in population conditions and related morph-specific costs and benefits is available. Our current understandings of emergence, maintenance and disappearance of multiple female morphs are even more limited. One way to examine the evolution of female polymorphism is to consider closely related species with known phylogenetic relationships. If species differ in presence/absence of multiple female morphs and in ecology then inspection of the phylogenetic tree will contribute to our understandings of female polymorphism.
sexual selection, polymorfism, damselflies, evolution
|Evolutionary Biology Group||unknown|
created:2011-12-14 14:18:59 UTC, source:iweto