Using vitellogenin (Vtg) gene as a biomarker, the possible role of selected endocrine modulators(EMs) such as methyl farnesoate (MF), 17-hydroxy progesterone (17-OHP), biochanin-A, methio-nine enkephaline (ME) and arachidonic acid on female reproduction in crab Oziothelphusa senex senex(O. senex senex) was elucidated in this study. The injections were given on 1st and 7th day of experi-ment (…