Regulation of insect oogenesis. More than an endocrine interplay

Abstract

Trabajo presentado en la 28th Conference of European Comparative Endocrinologists (CECE 2016), celebrado en Lovaina del 21 al 25 de agosto de 2016.Oogenesis is a crucial process in the animal kingdom to ensure the continuity of the species. Thus, it is not surprising that it is finely regulated. During the process of oogenesis, the ovarian follicle gets a series of signals that initiates competence, which will ultimately lead to maturation and oviposition. Insects are good models to study oogenesis as they have developed very different strategies to regulate it, and one of the most basic has been the design of different ovarian types. Two main types can be distinguished among insects: the panoistic and the meroistic. The panoistic is common in phylogenetically basal species, whereas the meroistic type predominates in distal insect groups. To study insect oogenesis we currently use the cockroach Blattella germanica as a model , a basal species with panoistic ovaries. The knowledge of this species can allow comparing its oogenesis with that of more mo dified species, like Drosophila melanogaster (with meroistic ovaries). In B. germanica , the juvenile hormone is the main reproductive hormone, involved in vitellogenesis control and oocyte maturation. We will review the role of juvenile hormone and its sig naling pathway, the function of ecdysone, which is necessary for chorion formation in adult cockroaches, and is also involved in the first steps of oogenesis, and the role of the Insulin pathway, which regulates tissue growth as well as vitellogenesis thro ugh the control of juvenile hormone synthesis. Finally, we will comment the involvement of these hormones in the signaling pathways (Hippo, Notch) that typically regulate insect oogenesis, in general.N