Liquid Fluorophore Taggants for Mark‐release‐recapture Research: a Survey of Potential Arthropod Targets

We evaluated a method for marking arthropods that could serve as a valuable tool for mark-release-recapture dispersal research. The taggants tested consisted of three liquid fluorophores labeled cartax green, magenta, and orange. The manufacturer markets these fluorescent markers as forensic theft deterrents. Specimens of 16 genera of arthropods were externally marked with either one of the colored fluorophores or with water (negative control treatment). The specimens were then qualitatively and quantitatively inspected for fluorescence 24 h later. For the qualitative analysis, three independent observers scored each specimen by direct observation for the presence of a fluorescent mark. The specimens were scored using a portable ultraviolet (UV) tube lantern and a specialized NIGHTSEA-brand LED UV light. The three fluorophores were readily detected on many but not all the species examined, regardless of the type of UV light used. Moreover, the NIGHTSEA LED light yielded fewer false-negative observer errors than the lantern. Each specimen's fluorescence was measured with an automated dual-wavelength microplate fluorometer for the quantitative analysis. Overall, the quantitative analysis was very reliable at detecting fluorescence on a few taxa [e.g., Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), Chrysoperla spp. (Neuroptera: Chrysopidae)], effective on most taxa, and unreliable on several others [e.g., Collops vittatus (Say) (Coleoptera: Melyridae), Geocoris spp. (Hemiptera: Geocoridae), Mecaphesa celer (Hentz) (Araneae: Thomisidae)]. The cartax green marker was more readily detected than the magenta and orange markers with both visual and automated detection. Overall, the results show that these fluorophores could be effective markers for many arthropod species.