Locating large insects using automated VHF radio telemetry with a multi‐antennae array

We describe an automated radio telemetry system (ARTS) designed for estimating the location of 0.50 g butterflies which was constructed with commercially available materials. Previously described systems were not designed to estimate fine‐scale locations of large insects within approximately 200 m2 study areas. The ARTS consists of four receiving stations. Each receiving station has four 3‐element, directional Yagi antennae (separated by 60) connected to an automated receiver that records detected power sequentially from each antenna. To develop and evaluate the ARTS performance, four receiving stations were installed in the corners of 4 and 6.25‐ha square fields with varying heights of vegetative cover. The location of a 0.22 g transmitter was estimated with a statistical method implementing both distance‐and angle‐power relationships. Calibrated model parameters were based on power detected from transmitters at known locations. Using independently collected data, model performance was evaluated based on estimated locations of a georeferenced stationary transmitter, a moving transmitter with a known georeferenced path and a transmitter attached to a monarch butterfly Danaus plexippus. Estimated locations were calculated as frequently as every 5 s, which is at least 12 times greater than the sampling frequency previously reported for tracking insects. When sufficient power data were received, the median estimated locations of a transmitter attached to an investigator's hat were