Endocrine peptides and insect reproduction

In insects, peptide hormones regulate many physiological and developmental processes such as growth, moulting, metamorphosis, reproduction, diapause, feeding and metabolism. This review focuses on those involved in reproduction, in particular vitellogenesis and oogenesis, spermatogenesis, ovulation and pheromone production. Most of these peptides regulate the production of the true gonadotrophic hormones (as in the case of allatostatins, allatotropins and ovary ecdysteroidogenic hormones) or the production of pheromones (as in the case of pheromone biosynthesis activating neuropeptides). Other peptides seem related to reproductive processes, but it is not clear whether they play a true regulatory role. Cloning approaches have greatly facilitated the solution of structural aspects of peptide research; the major challenge now is to approach the functional aspects.