Observations on cytoplasmic transport along ovarian nutritive tubes of polyphagous coleopterans.

The ovarioles of Coccinella and Tenebrio are shown to be telotrophic--a characteristic normally associated with hemipterans rather than coleopterans. The possess an anterior region of trophic cells and a chain of oocytes. The trophic cells are connected with the latter by a series of nutritive tubes, and autoradiography has shown that RNA is transported along the tubes to the oocytes. However, the system in these beetles differs markedly from that of hemipterans in that the nutritive tubes do not contain an extensive complement of aligned microtubules. The significance of this to both the mechanism and the selectivity of transport is discussed.