Ultrastructural studies of male‐incubated ovaries of the gypsy moth, Lymantria dispar

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Abstract
Ovaries from Lymantria dispar females were transplanted into an environment lacking the vitellogenin ligand; i.e., the male milieu. Transmission electron micrographs comparing the terminal oocytes of male‐grown ovaries and normal ovaries showed that yolk sphere diameters were reduced in the male‐grown oocytes. However, there were larger numbers of these small yolk spheres per unit area of cytoplasm, indicating that the coalescence of endosomes into yolk spheres is reduced in the absence of vitellogenin. Although there are larger numbers of yolk spheres in male‐grown oocytes, the smaller diameter of yolk spheres resulted in less area being taken up by yolk spheres per unit area of cytoplasm in male‐grown oocytes, yielding lowered yolk production. This lowered yolk production is a result at least in part of the lowered number of coated vesicles per unit area of submembrane space and in part of the reduced interfollicular spaces seen in male‐grown ovaries.