Discovering the Scent Sensor for Camphor in a Moth Species

Greg Howard
25th January, 2024

Image Source: Natural Science News, 2024

Camphor, a substance with a strong, penetrating odor, has long been used to keep insects away from stored products. Despite this, the moth Orthaga achatina, part of the Pyralidae family, has developed a taste for the camphor tree, Cinnamomum camphora, indicating an unusual evolutionary twist. Researchers looked into this phenomenon to understand how these moths interact with camphor, as understanding this could help in managing pests. The study revealed that adult moths, both male and female, are indeed attracted to the smell of camphor. This attraction indicates that the moths have adapted to use the scent as a way to locate camphor trees for food. It's an interesting case of an insect targeting a plant that produces a chemical supposed to deter pests. To delve deeper into this behavior, scientists studied the genetic makeup of O. achatina's sense of smell. They focused on the moth's antenna, the primary organ for detecting odors. After analyzing the genetic information from the antenna, they identified 40 different genes related to odor receptors. Out of these, only one specific gene, OachOR16 with its partner protein Orco, was responsive to camphor when tested in a lab setting using the membrane of Xenopus frog eggs. This test helped to isolate the specific gene-receptor combination that reacts to the smell of camphor. Further investigation using molecular docking, where scientists simulate how two molecules interact with each other, combined with site-directed mutagenesis, which is a method used to create specific changes in a gene, helped pinpoint the precise part of the gene that binds with camphor. They found that a particular component within the receptor molecule, known as the Ser209 residue, is crucial for this interaction. The results of this research not only bring to light the unusual attraction of O. achatina moths to camphor but also provide clear insights into the molecular underpinnings of this interaction. Moreover, pinpointing the Ser209 residue as a key factor in the binding process between the odor receptor and camphor opens up the possibility of developing new repellents. By targeting this interaction, it may be possible to create substances that can effectively deter these moths and potentially other insects, providing new strategies to protect stored products. This knowledge is valuable for pest management and could have broader implications for understanding how insects adapt to deterrents and evolve to exploit new resources.

Biochem Ecology Plant Science

References

Main Study

1) The Odorant Receptor Recognizing Camphor in a Camphor Tree Specialist Orthaga achatina (Lepidoptera: Pyralidae).

Published 24th January, 2024

https://doi.org/10.1021/acs.jafc.3c08877

References

Main Study

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