Meeting October 20th: Taste: from function to the emergence of a pest fly

Dear CES members,

Our next meeting will take place on October 20 at the Jones Auditorium, C.A.E.S., New Haven. Meet to socialize starting at 6:30 p.m. Refreshments will be provided. The business meeting starts at 7:30 and the presentation starts at 8 p.m. For those who prefer not to attend in person, please email ctentsoc@gmail.com for the Zoom link.

Title: Taste: From function to the emergence of a pest fly

Description:

Taste systems detect a vast diversity of toxins, which are perceived as bitter. When a species adapts to a new environment, its taste system must adapt to detect new death threats. We deleted each of six commonly expressed bitter Gustatory receptors (Grs) from Drosophila melanogaster. Requirements for these Grs varied in different neurons, and for different tastants in the same neuron. Surprisingly, some bitter responses required four Grs, and co-expression of these four Grs conferred the responses to a sugar neuron. Deletions also produced increased or novel responses, supporting a model of Gr-Gr inhibitory interactions. This work shows how the complex logic of bitter coding provides the capacity to detect innumerable hazards and the flexibility to adapt to new ones. We then examined bitter taste in the agricultural pest D. suzukii. Although most Drosophila species lay eggs in overripe fruit, D. suzukii lays eggs in ripe fruit. We found that changes in bitter taste perception have accompanied this adaptation. D. suzukii has lost 20% of the bitter-sensing sensilla from the major taste organ of the head. Physiological and behavioral responses to various bitter compounds are lost. Profiling of transcriptomes reveals reduced expression of several bitter Gr genes. These findings support a model in which bitter compounds in early ripening stages deter egg laying in most Drosophila species, but a loss of bitter response contributes to the adaptation of D. suzukii to ripe fruit.

Biosketch: Dr. Dweck has been a Chemical ecologist and Assistant Scientist II in the department of Entomology at the Connecticut Agricultural Station since January 2023. He earned a B.Sc. and M.Sc. at Cairo University, Ph.D. at the Max Planck Institute for Chemical Ecology, and conducted postdoctoral studies in the laboratory of Dr. John Carlson at Yale University. He was born in Giza, Egypt, and has lived in Sweden, Germany, and the United States. He is also a proud husband and father of two boys. His laboratory studies how crop pests find their host plants, communicate, and avoid danger using tools and techniques from various fields, including behavior, electrophysiology, analytical chemistry, molecular biology, and genetics.