Differentiation of the worker's ovary in Apis mellifera L. (Hymenoptera, Apidae) during life of the larvae

The aim of the present study is to characterize the way worker and queen ov aries differentiate in, Apis mellifera, a species with trophic determinatio n of female castes. A morphological study carried out with light and transm ission electron microscopy showed that the differences in ovary development between the two castes begin as soon as the differential nursing of larvae is initiated. The decrease in ovariole number in worker ovaries is due to a process of cell death occurring in germinative cells and autophagic regre ssion of somatic cells in the ovarioles that commence in the third instar l arvae and proceed until the fifth instar where the process is more intense. Germinative cell death leads to ovariole disintegration and incorporation of the remaining somatic cells of the latter into the stromatic cells in su ch a way that the total volume of the ovary is little affected during larva l development, although the ovariole number decreases. By the end of the la rval stage, loss of cells is observed among the stromatic cells of the ovar y. As a result, the ovary starts to decrease in volume and takes on the adu lt form.