Achieving high sexual size dimorphism in insects: females add instars

摘要: In arthropods, the evolution of sexual size dimorphism (SSD) may be constrained by a physiological limit on growth within each particular larval instar. A high SSD could, however, attained if larvae larger sex pass through higher number instars. 2. Based survey published case studies, present review shows that sex- related difference in instars is widespread phenomenon among insects. great majority species with sexually dimorphic instar number, females develop than males. 3. Female-biased final sizes was found to considerably exceed previously estimated median value for insects general. This suggests causal connection between female- biased SSD, and additional females. Adding an extra development allows insect increase its adult at expense prolonged development. 4. As instars, fully formed late ontogeny , schedules imaginal can optimised independently. No conflict selective pressures operating juvenile stages therefore expected. 5. most considered, also varied sexes. Phenotypic plasticity thus precondition evolve.