Drosophila suzukii, the spotted wing Drosophila, is an invasive pest of small fruits expanding its range around the world. A massive number of research papers concerning this species have been published recent years, including the studies about its egg-laying preference for various cues such as odors and tastes.
Because Japan is a native range of D. suzukii, we planned a research project to study natural genetic variation among the local populations of D. suzukii in their oviposition-site preference. However, what we experienced first was that D. suzukii lays only a few eggs in the experimental condition, making the oviposition assay inefficient and unreliable. Therefore, we started from seeking the condition with which D. suzukii lays more eggs.
At that time we were using 96-well plates for preparation of artificial oviposition-substrates that was presented to the flies exposing only its flat top surface for egg laying. But one day, some substrates had accidentally come out of the wells, and their spherical bottom surfaces had been exposed during the experiment. What we observed as a result was that D. suzukii laid many eggs on the spherical part of the substrates.
This finding led us to conduct a series of experiments confirming the preference of D. suzukii for a certain curvature of spherical surfaces. The results are now published as:
Akutsu, J., Matsuo, T.
Drosophila suzukii preferentially lays eggs on spherical surfaces with a smaller radius.
Scientific Reports 12, 15792 (2022).
https://doi.org/10.1038/s41598-022-20022-z
Using the spherical substrates, now we are able to make D. suzukii lays many eggs sufficient for evaluation of their preference, as well as for stable laboratory stock maintenance. We hope many researchers in this field are benefited with this method.