Ovaries were fixed for 15 min in 10% Formaldehyde and 0.2% Tween in Phosphate Buffered Saline (PBS‐T). Embryos were fixed for 5 min at the interface of 37% Formaldehyde and 100% Heptane. Embryos were then washed in PBS and PBS‐T and the vitelline membrane was removed manually using a sharp needle. Ovaries and embryos were incubated in blocking solution (10% Bovine Serum Albumin in PBS) for about 1 h at room temperature prior to staining. Primary and secondary immunostainings lasted at least 3 h in PBS‐T. Three washes of about 10 min each in PBS‐T were carried out between stainings and after the secondary staining. Primary and secondary antibodies were used at a concentration of 1:150.