Reporter of blood element transposition. Contains a complete copy of the blood retrotransposon (flanked by P-element ends) with an EGFP cassette inserted in the antisense direction in the non-coding sequence of blood. 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 blood element in the reporter transgene, which generates a new copy of blood containing EGFP without the disrupting intron.