A DsRed fluorescent protein marker under polyubiquitin promoter regulation allows visual and amplified gene detection of transgenic Caribbean fruit flies in field traps

Field population surveillance of a targeted insect pest species is critical in evaluating management programs such as the sterile insect technique. Fluorescent powder dyes currently used to distinguish released tephritids from the field population are not optimal in terms of reliability and human health issues. Genetically transformed tephritid species present the possibility of using fluorescent transgenes for marking. Here we studied the stability of DsRed fluorescence in transgenic flies maintained in aqueous torula yeast borax and propylene glycol. DsRed was stable in both solutions for three weeks by visual microscopic observations and could be used to unambiguously distinguish them from non-fluorescent wild type flies. To compensate for any potential ambiguity in visual identification a diagnostic PCR was developed that could specifically amplify the exotic heterologous marker gene. Therefore, the use of sterile transgenic insect strains carrying stably integrated fluorescent protein marker genes in biologically-based control programs could greatly improve released fly identification in pest management programs.