 RPCH was discovered in crustaceans and shown to be involved in concentrating red pigments, for sexual displays and a variety of other reasons.The similarity between AKH and RPCH is so significant that injecting insects with RPCH induces an AKH like response and "vice versa" 

AKH was first purified by an English group in 1976 and the chemical structure was determined to be a peptide hormone formed from 10 amino acids.This was the first instance where an insect peptide hormone had been identified.