Applying Satyrization to Insect Pest Control: The Case of the Spotted Wing Drosophila, Drosophila suzukii Matsumura

Abstract

Drosophila suzukii represents one of the major agricultural pests worldwide. The identification of safety and long-lasting tools to suppress its populations is therefore crucial to mitigate the environmental and economic damages due to its occurrence. Here, we explore the possibility of using satyrization as a tool to control the abundance of D. suzukii. By using males of D. melanogaster, we realized courtship tests, spermathecae analysis, and multiple-choice experiments to assess the occurrence and extent of pre- and post-zygotic isolation between the two species, as well as the occurrence of fitness costs in D. suzukii females due to satyrization. Our results showed that: (i) D. melanogaster males successfully courted D. suzukii females; (ii) D. melanogaster males significantly affected the total courtship time of D. suzukii males, which reduced from 22.6% to 6.4%; (iii) D. melanogaster males were able to inseminate D. suzukii and reduce their offspring, inducing a high fitness cost. Reproductive interference occurs at different steps between D. melanogaster and D. suzukii, both alone and in combination with other area-wide control approaches.

Keywords: asymmetric fitness cost; biological control; fruit fly; insect pests; interspecific interactions; reproductive interference.

Figure 1

Time budget of courtship behavior of D. suzukii and D. melanogaster males. (A) Percentage of the total time spent courting D. suzukii females by D. melanogaster males without D. suzukii males (light pale blue) and with D. suzukii males (dark pale blue). (B) Percentage of the total time spent courting D. suzukii females by D. suzukii males without D. melanogaster males (light pale blue) and with D. melanogaster males (dark pale blue). Black dot is box-plot outlier. Asterisk means Wilcoxon Mann–Whitney test p-value < 0.05.

Figure 2

Offspring originated from five pairs of Drosophila suzukii males and females with 0, 20, 40 or 60 D. melanogaster males. *** Wilcoxon Mann–Whitney test p < 0.001; ** Wilcoxon Mann–Whitney test p-value < 0.01. Black dots are box-plot outliers.