The olfactory system of insects is very different from ours or that of any other animal, and even today it raises many questions about its functioning and how it has evolved between different groups of insects.
This question has caused great interest among many scientists, including Vanessa Ruta and her research colleagues: taking advantage of recent advances in electron microscope research, they managed to find a way to try to solve the doubts surrounding the olfactory system of insects and their evolutionary relationship.
The main structures studied within this system are the odor receptors in insects . These were first identified by the neurobiologist Leslie Vosshall and thanks to her studies it has been possible to deepen to further understand this system.
To understand this study, we have to understand odors as specific chemicals that can travel in the air until specific cells receive, detect, and transmit the triggered signal to the brain. One of the factors that most caught the researchers’ attention was the fact that even though there were millions of cells with different receptors to detect specific odors, all of these worked in the same way.
Vanessa Ruta and her team of researchers came to describe the structure of the olfactory system in insects and how it works. These are channels – called ion channels – that serve as passageways that connect the exterior to the interior of the cell, and they only open if the receptor located on the exterior recognizes the foreign particle as an odor particle. If the outdoor receiver does not detect an odor, this channel will remain closed.
These experts discovered that, along with these receptors, there was a type of protein that remained constant throughout the wide variety of insects and their respective olfactory channels, the Orco protein.
This protein is the main one in charge of keeping the entire receptor complex together and allows the channels to function properly. Orc allows the regions in charge of receiving odors to undergo chemical changes without affecting the entire channel because it keeps them together despite possible alterations.
Thanks to this protein, the great variety of receptors in the olfactory channels of insects can exist, allowing the receptors of each type of insect to have been evolutionarily specialized to smell different elements of their environment: different types of food, odors related to the detection of hazards, possible pairings, etc. Thanks to this, for example, butterflies are able to detect the nectar of flowers.
This study on the olfactory system of insects gives rise to future research that can positively affect human health. The researchers who carried it out are hopeful that future research can develop, for example, mosquito repellants and other similar pests that are associated with the spread of serious diseases, such as malaria.
Butterwick, J.A., del Mármol, J., Kim, K.H. et al. Cryo-EM structure of the insect olfactory receptor Orco. Nature 560, 447–452, 2018. Doi:10.1038/s41586-018-0420-8
