Harmonic radar technology has been used to track the dispersal of tagged (wire attached to a Schottky diode ) insects. This tag uses the original radar signal as an energy source, re-emitting a harmonic of the transmitted wavelength. A light-weight (8 kg), handheld transmitter/receiver is commercially available from RECCO Rescue Systems Inc.. Our goal is to develop and employ this harmonic radar tracking system to monitor the movement of Carabids in agricultural ecosystems. In 2001 we identified a commercial source of diodes compatible with the RECCO transmitter/receiver, and tested several diode and wire combinations. We achieved a maximum detection range of 70 m with a 16 cm long dipole (diode attached to 8 cm pieces of wire) held 1 m above the ground. In corn and soybean fields, large carabids (Scarites quadriceps and Harpalus spp.) could carry and be recaptured even when burrowed completely out of sight. Carabids were able to move more easily through ground cover when pulling a monopole (diode attached to one section of wire, diode attached to insect) then a dipole antenna. In 2002 we released 10 Scarites spp in a cornfield at 4:00 pm and 18 hrs later recaptured 7 using an 8 cm, 100 mg monopole copper wire tag,. Recaptured beetles averaged a total displacement of 2.5 meters, ranging from 0.48 m to 7.82 m (buried 9 cm into soil). We will test lighter weight tags using a fine gauge (0.07 mm), Teflon coated copper wire, selected for its low weight and flexibility.
Species 1: Coleoptera Carabidae Scarites quadriceps
Species 2: Coleoptera Carabidae Harpalus
Keywords: radar, dispersal
Back to Student Competition Display Presentations, Subsection Cd. Behavior and Ecology
Back to Student Competition Poster
Back to The 2002 ESA Annual Meeting and Exhibition