locust

The migratory locust Locusta migratoria is an economically important crop pest that is said to have come to Egypt in the Old Testament as the eighth of the ten biblical plagues, "to devour all that plants that grow."

The migratory locust is rarely found in Europe, but in Africa and Asia it not only causes millions of dollars' worth of damage but also has a deadly impact on local people, threatening their food and their very existence.

The locust antennal lobe has a unique and unconventional neuronal architecture with more than 2000 spherical functional olfactory units, the glomeruli, whereas most other insects have only between 20 and 300 glomeruli in the antennal lobe.

"Our goal was to solve the long-standing puzzle of how odors are encoded in the extremely large population of glomeruli, the structural and functional units in the antennal lobe of migratory locusts. This highly complex architecture of the locust antennal lobe has been observed for decades, but the underlying mechanisms of odor coding have remained a mystery due to the lack of suitable methods," says Xingcong Jiang, first author of the study.

"Our results reveal an unusual functional ring-shaped organization of the antennal lobe consisting of specific glomerular clusters. This glomerular arrangement, which we could confirm by targeted genetic expression of a well-characterized olfactory receptor, is present throughout development, and the pattern of olfactory coding within the glomerular population is consistent at all developmental stages, from the first nymph stage to the adult locust," summarizes Silke Sachse, head of the Olfactory Coding Research Group at the Max Planck Institute, one of the study leaders.