Reporter of 3S18 element transposition. Contains a complete copy of the 3S18 retrotransposon (flanked by P-element ends) with an EGFP cassette inserted in the antisense direction in the non-coding sequence of 3S18. The EGFP sequence contains a disruptive intron that can be spliced during transcription of the retrotransposon, but not during transcription of EGFP. Thus, EGFP protein is only expressed after mobilization of the 3S18 element in the reporter transgene, which generates a new copy of 3S18 containing EGFP without the disrupting intron.