We developed an experimental system for monitoring multiple bumble bees foraging on electric artificial flowers with a known rate of nectar secretion, by combining LED (Light Emitting Diode) based detection technology and RFID (Radio Frequency Identification) based identification technology. Using data on 2 workers of Bombus impatiens that were tagged with small chips and allowed to forage on these flowers in a cage, we demonstrate that our system is capable of tracking movement patterns, reward history, and foraging performance of individuals at large spatial scales.
The entire system is comprised of both instrumentation and software. The RFID reader, IR detector and the Feeder make up the instrumentation, while the Data logger is implemented via software.
The RFID reader and IR detector are electronic sub-systems that serve as inputs to the PC. The Feeder is a mechanical system whose only function is to provide each station with a steady stream of nectar. The Data logger is a software system that runs on the PC, and gathers data based on the inputs from the RFID reader and IR detector.
The RFID readers communicate with software via the USB. Due to the design of the USB protocols each reader is assigned an ID in an unpredictable manner. This means that every time the system is started, the readers loose sync with their associated IR detector.
The system is calibrated using a setup routine. The technician has to block a single IR detector and provide that RFID with a tag to read. Once the software routine detects the block signal it cycles through all the readers one at a time until a tag is read. When a reader is found that responds with a tag number, that reader is assigned to the IR detector that initiated that search cycle. The technician continues this for each and every flower in the field.
Once calibrated, the software receives the signal form the hardware by reading data from RAM, which is mapped to a known address by the DIO card. The software checks for any change in data at that location. If the change indicates that a bee has arrived at that location, the software issues the command to the RFID reader at that location to power up its antenna and to take a reading.
When a change occurs that indicated that the bee has vacated the feeder, the flower location, the arrival time, the departure time, and the RFID tag number is logged to a data file. The software graphically displays when there is a bee is at a flower, and its RFID tag number once read.
Wrote a program to collect data from USB RFID tag readers. Adapted an RFID card reader for the purpose of tracking the movement of bees. Constructed classes in Visual Basic to handle the operation of each RFID reader. Programmed each instance of the class to be created at run-time and to run independently from each other.
Exploited multi-threading to maximize the performance of each reader. Integrated the 16 readers in a network and maintained their individual polling rate. Developed a GUI to incorporate all previously written features. Wrote a program to collect data from RFID tag and record it in a log file. Contact maintained with end users to make the software more user friendly and add in any changes and suggestion presented by the client.