XO type sex-determination

Explanation

XO type sex-determination is found in a large number of insects, e.g. grasshopper, etc. It includes homogametic females and heterogametic males.
In this type, all the ove bear a X-chromosome, while sperms bear only either X-chromosomes or zero chromosome along with the other chromosomes (autosomes).
Eggs fertilised by sperms having an X-Chromosomes become females and those fertilised by sperms that do not have X-chromosome become males.