An Insect Monitoring Radar (IMR) was employed to compile statistics on the nocturnal migratory flights of locusts at Longreach, inland northern Australia between December 1994 and January 1996. The IMR is a ground-based instrument that operates unattended and employs a conical scan/linear polarisation technique to provide information on the mass, shape, and trajectory parameters of overflying insects; an alternative observation mode allows the frequencies of the insects’ wingbeat to be recorded. Observation summaries can be disseminated via the telephone network.
The Longreach region supports significant populations of both Australian plague locusts (Chortoicetes terminifera) and spur-throated locusts (Austracris guttulosa); the latter predominated during the observation period and were surveyed by conventional region-wide transect methods. Seasonal variations in IMR estimates of migration intensity and target identity correlate with locust survey and light-trap data.
IMRs provide a means of detecting and quantifying locust and grasshopper migratory flights. IMR data outputs can be integrated into models of the spatio-temporal dynamics of insect populations, and incorporated into procedures for the operational forecasting of these and other migratory pests.