Conference of European Comparative Endocrinologists (CECE2008) edition:24 location:Genoa, Italy date:2-6 September 2008
The desert locust, Schistocerca gregaria, can undergo a density-dependent phase transition between a cryptic solitarious and a swarming gregarious phase that differ in many aspects of behaviour, physiology and morphology. The first characteristic that changes during phase transition is the behaviour. The gregarious behaviour is triggered by repeatedly touching the hind legs of solitarious locusts. This reflects conditions in nature where they come together because sources have become rare, and thus the gregarious phase is necessary to migrate to more favourable places. The signal is transmitted trough metathoracic nerve five, which is octopaminergic. Octopamine, a biogenic amine and most likely the invertebrate homologue to vertebrate noradrenalin, functions as a neuromodulator, neurotransmitter, and neurohormone. It plays a prominent role in influencing multiple physiological events. Octopamine exerts its effects by binding to specific proteins that belong to the superfamily of G protein-coupled receptors (GPCRs) and share the structural motif of seven transmembrane domains. We received a partial sequence of a putative octopamine receptor from Prof. W. Blenau (Potsdam, Germany). We completed the sequence and studied the expression pattern in the solitarious and the gregarious phase and also during phase transition in S. gregaria. We also looked at the possible effects of RNAi of this receptor on the behavioural phase change.