Since the feeding strategy of parasitized wasps is focused on EFNs of the calyx, we analysed the distribution, activity and morphology of EFNs under a Leitz DM-RB Fluo Optic microscope equipped with a digital Nikon DS-L1 camera (LM) and a QUANTA-200 FEI environmental scanning electron microscope (ESEM), operating at low vacuum (pressure 0.53 Torr).
To describe the synthesis activity of EFNs, histochemical features of their secretions were observed under a light microscope (LM). Samples were fixed in FAA solution for 7 days, embedded in historesin (Technovit 7100; Radnor, PA, USA) and dyed with Toluidine Blue for a general survey, Sudan III/IV for total lipids, PAS reaction for total polysaccharides, and Ferric trichloride for polyphenols. Moreover, ultrastructure was described under a Philips EM-300 transmission electron microscope (TEM). Calyx fragments were fixed in 2.5% glutaraldehyde and 0.1 M phosphate buffer at pH 7.2, post-fixed in 2.0% osmium tetroxide, dehydrated in ascending ethanol series up to absolute and embedded in Spurr resin. The ultrathin sections were contrasted with uranyl acetate and lead citrate.
To describe the synthesis activity of EFNs, histochemical features of their secretions were observed under a light microscope (LM). Samples were fixed in FAA solution for 7 days, embedded in historesin (Technovit 7100; Radnor, PA, USA) and dyed with Toluidine Blue for a general survey, Sudan III/IV for total lipids, PAS reaction for total polysaccharides, and Ferric trichloride for polyphenols. Moreover, ultrastructure was described under a Philips EM-300 transmission electron microscope (TEM). Calyx fragments were fixed in 2.5% glutaraldehyde and 0.1 M phosphate buffer at pH 7.2, post-fixed in 2.0% osmium tetroxide, dehydrated in ascending ethanol series up to absolute and embedded in Spurr resin. The ultrathin sections were contrasted with uranyl acetate and lead citrate.