Gynandromorphs and intersexes: potential to understand the mechanism of sex determination in arthropods

*[Arthropods are sexually dimorphic. An arthropod individual usually differentiates into a male or a female. With very low frequencies, however, individuals with both male & female morphological characters have repeatedly been found in natural & laboratory populations of arthropods. Gynandromorphs (i.e., sexual mosaics) are genetically chimeric individuals consisting of male & female tissues. On the other hand, intersexes are genetically uniform (i.e., complete male, complete female or intermediate in every tissue), but all or some parts of their tissues have either a sexual phenotype opposite to their genetic sex or an intermediate sexual phenotype. Possible developmental processes (e.g., double fertilization of a binucleate egg, loss of a sex chromosome or upregulation /downregulation of sex-determining genes) & causal factors (e.g., mutations, genetic incompatibilities, temperatures or endosymbionts) for the generation of gynandromorphs & intersexes are reviewed & discussed]