The onset of vitellogenesis in Rhodnius prolixus is marked by a reduction in the height of the follicle cells. This decrease is not observed in follicle cells from allatectomized females. Estimates of the changes in cross-sectional area of the cells suggest that the cells shrink to about 50% of their original volume as the result of JH action.
Determination by interference microscopy of the volume of isolated living follicle cells before and after exposure to JH also suggest that the volume is reduced to 50 % of the original volume as a result of JH action. There was no decrease in volume of follicle cells from allatectomized females following exposure to JH.
During mid to late vitellogenesis in vivo, an increase in cell volume was measured, an increase that possibly reflects an increase in cellular dry mass.
It is concluded that follicle cells normally respond to JH by pumping out fluid, thus reducing their volume, and leading to the development of spaces between the cells.
Note: This work is supported by the National Research Council of Canada