Central Science Laboratory, Sand Hutton, York, YO41 1LZ, UK.
Early detection of stored product pests plays an important part in improving food quality by reducing contamination and spoilage. The effectiveness of traps used to monitor insect pests can be enhanced by the incorporation of pheromone lures. An understanding of olfactory perception in insects at the molecular level could further our knowledge on the mechanisms that result in pheromones and food volatiles eliciting certain behaviours. This could aid research for better detection by revealing features of molecules which are essential for recognition by odorant binding proteins (OBP's) and receptors, leading to the development of analogues of natural pheromones. The major insect pests of stored products are Coleoptera but until recently there has been no published work on OBP's in Coleoptera. We have attempted to identify a pheromone binding protein (PBP) for stored product beetles using Tenebrio molitor as a model. Female T. molitor produce a sex pheromone, 4-methylnonanol, to which the males respond. There is also evidence in the literature that male T. molitor produce a pheromone. Studies have been undertaken using various methods including polyacrylamide gel electrophoresis (PAGE) and the use of tritiated 4-methylnonanol to determine whether putative OBP's are present in T. molitor. The relative merits of the different techniques used are discussed. Tentative evidence has been obtained for a protein which is present in antennae but not in legs, and is more abundant in males than females. However, this result has proved difficult to replicate.