Scientists at The Connecticut Agricultural Experiment Station (CAES) announced on March 26 that they have discovered key cellular and molecular changes in the olfactory system of the spotted wing Drosophila (Drosophila suzukii), which allow this pest to shift its preference from overripe to fresh, ripe fruit. This research was published in the Proceedings of the National Academy of Sciences.
The findings are significant because the spotted wing Drosophila has caused major economic losses for U.S. growers by infesting soft fruits such as berries and cherries while they are still marketable. Unlike most fruit flies, this species can lay eggs inside intact, ripening fruit due to a serrated ovipositor, leading to maggot development and reduced crop value.
Jason C. White, Director of The Connecticut Agricultural Experiment Station, said: “Beyond addressing a fascinating biological question how sensory systems evolve to allow an insect to break bad this work is essential for developing new environmentally benign tools to reduce the damage caused by this pest.” Dr. Hany K. M. Dweck, lead contact for the study and head of CAES’s Chemical Ecology Laboratory, said: “We screened every olfactory neuron in SWD and its relatives to identify the neurons that have changed specifically in SWD. We observed functional changes in a small subset of olfactory neurons, characterized by a loss of responses to several fermentation-related volatiles and a gain of sensitivity to fruit-ripening and green-leaf volatiles. This shift in sensory tuning may help explain the species’ shift in preference toward ripe fruit.”
Dr. Qi Xue, first author of the study and postdoctoral scientist at CAES, said: “After identifying the olfactory neurons that differ in their odorant responses in SWD compared with its relatives, we used molecular genetics, protein modeling, and gene editing to uncover the mechanisms underlying these changes.” Xue also explained that CRISPR/Cas9 gene editing combined with behavioral assays demonstrated two odorant receptors are essential for locating fresh ripe fruit: “To establish a causal link between these cellular and molecular changes and SWD’s preference for ripe fruit…we demonstrated that two of the odorant receptors expressed in these neurons are essential for locating fresh, ripe fruit.”
According to Dr. Dweck: “This work also has practical applications…Understanding the olfactory pathways involved enables strategies similar to those used in drug discovery—such as chemoinformatics…to screen millions of compounds…These compounds can then be used to develop lures for monitoring and managing SWD populations.”
The Connecticut Agricultural Experiment Station receives support from its Research Foundation as noted on its official website. It enhances quality of life statewide through research addressing agricultural challenges as well as public health concerns according to CAES. The organization maintains its main campus in New Haven according to CAES.
CAES is governed by an eight-member Board of Control under statutory authority according to CAES, was established as America’s first agricultural experiment station according to CAES, serves as a pioneering research institution focusing on scientific studies related not only agriculture but also public health issues statewide while providing services such as soil testing alongside educational programs—and partners with various institutions across Connecticut according to CAES.
