Speaker
Description
The desert locust Schistocerca gregaria is capable of forming destructive swarms of millions of individuals, causing enormous agricultural and economic damages. The behaviours of this species, such as swarm formation and food search, are largely driven by chemosensory cues from the environment. In insects, including S. gregaria, the role of odorant receptors (ORs) expressed on the antennae in the detection of relevant odorants and pheromones has been extensively demonstrated. However, transcriptome and reverse transcription-PCR (RT-PCR) analyses revealed ORs also in other parts of the insect body, including tarsi, wings, and the ovipositor. The functional relevance of OR-expressing cells apart from the antenna is still largely elusive. As a first step to elucidate the functional implication(s) of “extra antennal” OR- positive cells in S. gregaria, we aimed at identifying olfactory proteins in other tissues of the desert locust. RT-PCR analyses revealed expression of the odorant receptor co- receptor (ORCO) in various locust body parts implicated in chemosensory functions in other insects, including the tarsi. Through fluorescence immunohistochemistry on tarsal sections with antibodies against ORCO and a neuronal marker, ORCO was found to be localized in neurons associated with distinct sensilla types, suggesting a chemosensory function of these cells and sensilla. Moreover, by RNA sequencing and RT-PCR we identified a number of OR-types abundant in tarsal tissue. In ongoing work we try to localize cells in the tarsi expressing these OR-types. To target the potential chemosensory function of identified neurons in the tarsi, we intend to employ OR/ORCO knockdown strategies (RNAi) in combination with electrophysiological approaches.
