Fig. 1

L. cuprina transgenic sexing strain DH6 carrying the two lethal effectors. a Schematic illustration of the two lethal effectors strategy. The FL3 piggyBac construct contains a ZsGreen marker gene driven by Lchsp83 promoter and a sex-specific tTA overexpression cassette (tetO21-Dmhsp70 core-Chtra intron-tTA-SV40 polyA). The EF1 piggyBac construct contains a DsRed marker gene driven by the Lchsp83 promoter and a sex-specific Lshid ^Ala2 effector cassette (tetO21-Lchsp70 core-Chtra intron-Lshid ^Ala2-SV40 polyA). In the absence of tetracycline, tTA is overexpressed from the FL3 transgene causing female lethality at the pupal stage. However, in the two lethal effectors strategy tTA would also activate expression of Lshid ^Ala2, which acts as the second lethal effector. Consequently, females die at an earlier late-larval stage because of activation of apoptosis. b DH6 (FL3#2; EF1#12) shows both green and red fluorescence in third instar larvae and young adults