Novel staining procedures for whole mount preparations of greater wax moth (Galleria mellonella) embryos: toluidine blue-rhodamine B, plus calcofluor white

Although hematoxylin and eosin (H & E) staining of sectioned embryonic insect material is widely used, it is time-consuming and may not provide sufficient information. We evaluated new staining procedures for embryonic whole mounts of the greater wax moth, Galleria mellonella. We compared a combination of toluidine blue and rhodamine B (TB-RB) to H & E; we also investigated calcofluor white (CFW) staining. TB-RB staining produced staining similar to H & E. TB-RB staining was less time-consuming and improved visualization of the blastoderm and its differentiation into the germ disk and serosa membrane. CFW enhanced details of mitosis in nuclei post-fertilization and stained the primary serosal membrane. Staining of whole mounts with TB-RB and CFW enabled embryonic staging that was more rapid, convenient and effective than the routine approach using H & E and fluorescent probes.