Assessment of non-methyl eugenol-responding lines of Bactrocera dorsalis (Diptera: Tephritidae) males on lure response and mating

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a major global pest of fruits. Currently, the sequential male annihilation technique, followed by the sterile insect technique has been used to significantly reduce the population of feral males in this species. However, issues with sterile males being killed by going to male annihilation traps have reduced the efficacy of this approach. The availability of males that are non-methyl eugenol-responding would minimize this issue and increase the efficacy of both approaches. For this, we recently established two separate lines of non-methyl eugenol-responding males. These lines were reared for 10 generations and in this paper, we report on the assessment of males from these lines in terms of methyl eugenol response and mating ability. We saw a gradual decrease in non-responders from ca. 35 to 10% after the 7th generation. Despite that, there were still significant differences until the 10th generation in numbers of non-responders over controls using laboratory strain males. We did not attain pure isolines of non-methyl eugenol-responding males, so we used non-responders from the 10th generation of those lines as sires to initiate two reduced-responder lines. Using these reduced responder flies, we found that there was no significant difference in mating competitiveness when compared with control males. Overall, we suggest that it may be possible to establish lines of low or reduced responder males to be used for sterile release programs, that could be applied until the 10th generation of rearing. Our information will contribute to the further development of an increasingly successful management technique incorporating the use of SIT alongside MAT to contain wild populations of B. dorsalis.