Sexual size dimorphism and the integration of phenotypically plastic traits.

Sexual size dimorphism ( SSD) reflects adaptive differences in male and female reproductive roles. Understanding the mechanisms generating SSD is of broad ecological and evolutionary interest, because body size is closely linked to fitness., Sex-specific phenotypic plasticity in growth as a response to environmental conditions represents one of the major sources mediating variation in SSD., We investigated phenotypic plasticity associated with predation and seasonal time constraints in development as a source of SSD in the Azure damselfly, Coenagrion puella. We complemented this with an analysis of trait correlations (integration) of body size with behavioural, physiological and life-history traits to investigate how dimorphism manifests., Our results reveal that: (i) plasticity in SSD is mediated by environmental variation; and (ii) environment-dependent, sex-specific changes in the association of body size with growth rate and fat storage mediated changes in the offset of SSD., Our results highlight sex-specific trait responses to the environment channel manifestation of SSD. These findings may be crucial to understanding large parts of the widely documented intraspecific variation of SSD. [ABSTRACT FROM AUTHOR]