Tracking 3 wasp species (Hymenoptera: Vespidae) with harmonic radar: toward an accessible, inexpensive colony location tool.

Tracking tagged individuals is an emerging tool to locate invasive wasp nesting sites. Both tag size and transmitter/transceiver cost can limit the applicability of these technologies for eradication measures. This pilot study used a combination of lightweight, inexpensive harmonic radar tags fabricated with superelastic nitinol wire, and off-the-shelf transceivers designed for backcountry rescue. Larger tags weighing ~10 mg (~14 mg with adhesive) were used to track three vespid wasps, Delta esuriens (F.), Polistes aurifer Saussure, and Vespula pensylvanica (Saussure), while smaller tags ~5 mg (~8 mg with adhesive) were used only with V. pensylvanica. Wasps were successfully tagged in both laboratory and field settings. Tagged P. aurifer were shown to be flight capable in a large outdoor field cage. Subsequently, wasps were tracked in a macadamia nut field (D. esuriens and P. aurifer), a coastal habitat (D. esuriens), and in Hawai'i Volcanoes National Park (V. pensylvanica). Flight paths up to 6 steps (maximum 126.7 m) were recorded for D. esuriens (maximum single flight 76.6 m). Vespula pensylvanica were tracked to one nest; several other attempts failed to identify a nest location but did demonstrate the practicality and limitations of following wasps through dense vegetation. Additionally, we demonstrated that V. pensylvanica would carry off tags embedded in small pieces of meat although this technique did not lead to the discovery of any nests. This study demonstrates the feasibility of using an inexpensive method to track wasps, potentially allowing for a rapid and simplified method of locating invasive wasp nests.