[Neuroendocrine control of reproduction in insects]

The major reproductive processes in insects are regulated by neurohormones. Neurohormones act according to two distinct modes, either directly upon the target organs or by controlling the activity of the endocrine glands which, in turn, influence the different reproductive steps. The majority of identified neurohormones are produced in the brain; their origin in particular neurosecretory cells, while established in a few cases, is often unknown. Neurohormones are also produced, outside the brain, in the ventral nerve cord ganglia. They intervene namely in the regulation of egg-laying. The best known release sites of neurohormones are the cephalic and metameric neurohemal organs. Moreover, the neurohormones are also released in close contact with or within the target organs.