Abstract
Ecdysteroids and juvenile hormones play a key role in the regulation of development and reproduction of insects. The search for adenotropic factors that regulate the synthesis of these hormones led to the isolation and identification of a large number of neuropeptides with ecdysio- or allatoregulating functions from various insect orders. Many of these peptides are multifunctional and widespread among insects. This review mainly deals with the isolation, identification and physiological actions in vitro and in vivo of ecdysiostatic and allatostatic peptides isolated from the Mediterranean field cricket, Gryllus bimaculatus, and presents some previously unpublished results. The identified peptides and their physiological actions are compared with those isolated from other insect orders. It seems likely that in addition to the ecdysio- and allatoregulating factors, peptides of the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family might also be involved in the regulation of insect development and reproduction. These latter peptides are well known for their energy-mobilizing function in flying insects, but they also regulate other energy-demanding events such as egg-production. The possible roles of these neuropeptides and their interactions with other hormones are discussed.
