Developing heterospecific sterile insect technique for pest control: insights from the spotted wing fly Drosophila suzukii

Abstract

Background: Reproductive interference (i.e. sexual interaction between males of one species and females of another species that reduce the fitness of one or both the interacting individuals) is an important species interaction significantly affecting population dynamics and persistence. However, its exploitation in pest control remains overlooked. Here, we investigated the possible integration of reproductive interference into the sterile insect technique (SIT) to develop a heterospecific SIT (h-SIT). Under this approach, contrary to the classic SIT, sterile heterospecific males from closely related, nonpest species are released to compete with the pest population for mates. To this end, we focused on the invasive pest species Drosophila suzukii and used D. melanogaster as the control species. First, we investigated the effect of irradiation on D. melanogaster sterility and longevity. Then, we tested the mating performance of irradiated males and their ability to reduce the D. suzukii fitness.

Results: We found by microcosm experiments that: (i) irradiation induced high levels of D. melanogaster male sterility without reducing longevity; (ii) irradiated D. melanogaster males court D. suzukii females as much as D. suzukii males do, and they couple, mate with and inseminate heterospecific females; (iii) irradiated D. melanogaster males significantly reduce the offspring of D. suzukii females under two different species ratios.

Conclusion: Our results provide the first foundations for the development of a h-SIT against D. suzukii, an approach which can be tested against other groups of pest species. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Keywords: Drosophila melanogaster; Drosophila suzukii; pest control; reproductive interference; sterile insect technique.

Figure 1

Effect of irradiation on sterility of Drosophila melanogaster males. Comparison between the offspring originated from unirradiated D. melanogaster females coupled with unirradiated D. melanogaster males (green column and pink column, respectively) and irradiated at 60 and 80 Gy (orange and blue column, respectively). Different letters indicate significant differences by Tukey multiple comparisons tests (P < 0.05). Boxplots show median values (middle line), interquartile range (box) and range values.

Figure 2

Effect of irradiation on sterility of Drosophila melanogaster females. Comparison between the offspring originated from unirradiated D. melanogaster females coupled with unirradiated D. melanogaster males (green and pink columns, respectively) and irradiated females at 80 Gy (blue column). Different letters indicate significant differences by Tukey multiple comparisons tests (P < 0.05). Boxplots show median values (middle line), interquartile range (box) and range values.

Figure 3

Effect of different treatments on the longevity of Drosophila melanogaster males. Kaplan–Meier survival curves for each condition are shown. The P‐value of the log‐rank test also is shown.

Figure 4

Mating performance of irradiated Drosophila melanogaster males in no‐choice tests. Time spent in conspecific and heterospecific courtship behavior by unirradiated and irradiated D. melanogaster males, and unirradiated D. suzukii males. Percentage of the total time spent courting D. melanogaster females by unirradiated D. melanogaster males (orange column – conspecific courtship); percentage of the total time spent courting D. melanogaster females by irradiated D. melanogaster males (green column – conspecific courtship); percentage of the total time spent courting D. suzukii females by irradiated D. melanogaster males (blue column – heterospecific courtship); percentage of the total time spent courting D. suzukii females by unirradiated D. suzukii males (pink column – conspecific courtship). Tukey multiple comparisons tests (P > 0.05). suz = suzukii; mel = melanogaster. Boxplots show median values (middle line), interquartile range (box) and range values.

Figure 5

Mating performance of irradiated Drosophila melanogaster males in choice tests. Time spent in courting Drosophila suzukii females by D. suzukii and irradiated D. melanogaster males. Percentage of the total time spent courting D. suzukii females by irradiated D. melanogaster males and D. suzukii males when placed together (green and orange column, respectively) Wilcoxon–Mann–Whitney U‐test P > 0.05. Boxplots show median values (middle line), interquartile range (box) and range values.

Figure 6

Effect of irradiated Drosophila melanogaster males on D. suzukii fitness. Offspring originated from five pairs of D. suzukii without irradiated D. melanogaster males (green column) and with 40 (orange column) or 60 (blue column) males. Different letters mean significant differences by Tukey multiple comparisons tests (P < 0.05). Eighteen replicates were carried out for the condition without D. melanogaster males. Nine replicates were carried out for each of the two conditions involving the presence of D. melanogaster males. Boxplots show median values (middle line), interquartile range (box) and range values.