An effective fluorescent marker for tracking dispersal of small insects with field evidence of mark release recapture of Trissolcus japonicus

Authors: RYAN, PAUL - Oregon State University; Hagler, James; Janasov, Eric; MCDONALD, NICHOLAS - Oregon State University; VOYVOT, SALIAH - Ege Forestry Research Institute; Lee, Jana

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2024
Publication Date: 6/29/2024
Citation: Ryan, P.L., Hagler, J.R., Janasov, E.G., McDonald, N.S., Voyvot, S., Lee, J.C. 2024. An effective fluorescent marker for tracking dispersal of small insects with field evidence of mark-release-recapture of Trissolcus japonicus. Insects. 15(7):487. https://doi.org/10.3390/insects15070487.
DOI: https://doi.org/10.3390/insects15070487

Interpretive Summary: Understanding how far insects move enables us to predict their movement on a farm. Movement can be studied by marking insects, releasing them and recapturing them. We tested fluorescent water which is used in forensics to mark money as a way to mark 3 species of small parasitic wasps and the fly pest. Water marking is convenient and easy to detect on insects with UV light. This marking was effective and persisted on the insects for 20 days while having no negative impact on their longevity, movement or parasitism. This work will allow for an improved understanding of parasitoids and pests movement and role of field to field movement in pest outbreaks and control.

Technical Abstract: Understanding insect dispersal helps us anticipate the spread of insect pests and their natural enemies. Dispersal can be studied by marking insects, releasing them, and recapturing them. Techniques to mark insects should be convenient, economical, and persistent. At present, there are limited options for marking small parasitoids that do not impact their fitness and dispersal ability. We evaluated a commercially available fluorescent marker used in forensics since it could easily be detected by UV light and would require minimal labor to process samples. This marking technique was evaluated by misting four species: an egg parasitoid of Halyomorpha halys, Trissolcus japonicus, the pest Drosophila suzukii, its pupal parasitoid Pachycrepoideus vindemiae, and its larval parasitoid Ganaspis brasiliensis. We evaluated the persistence of the mark on the insects' body over time, and impact on parasitoid longevity, parasitism, locomotor activity (walking in an activity monitor), and flight takeoff. The green marker persisted for more than 20 days on the four species. Marking generally did not reduce survival of the parasitoid during the first days when parasitoids are expected to thrive in the field. Marking did not reduce parasitism rate, nor locomotor activity of the three parasitoids, nor takeoff of T. japonicus or P. vindemiae. Marked T. japonicus were recaptured in the field up to 100 m away from the release point and three weeks after release indicating that the marker persisted in the field and this technique is a viable method for studying field dispersal of parasitoids.