Meeting Abstract

S3.4  Sunday, Jan. 4  The role of insect adipokinetic hormones in locomotion, development and reproduction LORENZ, M.W.*; GAEDE, G.; University of Bayreuth; University of Cape Town matthias.lorenz@uni-bayreuth.de

Many insect hormones have a direct or indirect influence on metabolic events in insects. One of the true metabolic hormones is the adipokinetic hormone (AKH) which has been compared in some of its actions with vertebrate hormones such as glucagon or adrenalin. In addition to the well-established glucagon-like effects, many additional functions of this small neuropeptide have been established. The present paper briefly summarises the multiple actions of AKH and focuses on three situations where the energy demand is high: locomotion, reproduction, and moulting. During flight, aerobic metabolism is increased up to 100-fold; substrates such as lipids, carbohydrates or proline are mobilised from the fat body. Mobilisation, transport, and uptake of these substrates are specifically regulated by AKH. Recent work on other locomotory behaviour such as swimming or walking, clearly demonstrates a regulatory function of AKH. Females of flying insects are faced with the problem of energy allocation during vitellogenesis. Some species produce huge numbers of eggs that are rich in energetic substrates at the cost of reduced flight ability (oogenesis-flight syndrome). We show that AKH is involved in the control of egg production and evaluate the role of AKH in regulating energy allocation. Finally, larval development is characterised by phases of starvation due to the necessity to empty the gut prior to moulting. Thus, starvation coincides with increased energy demand for the synthesis of the new cuticle and the emergence of the insect from the old cuticle. On the basis of these events, we discuss the significance of AKH in larval insects.