## 4 Discussion
The average weight of the tags used in our study was \(\approx\)5 mg, which is less than 3% of the average queen weight (\(\approx\)190 mg). Previous studies have indicated that effective tags should represent less than 5% of the body mass [32] or 2% only for flying animals [33]. Honey bees were successfully tracked by harmonic radar system using transponders weighing between 12 and 15 mg [13]. Despite these estimations, the data obtained from our study clearly indicate that virgin queens of \(\approx\)190 mg were able to perfectly perform their nuptial flight while tagged by 5 mg Hitachi tags described in this study. However, the quality of the mating process remains to be studied and investigated. If other types or sizes of transponders are used [34], the height of the funnel should be adjusted to capture the transponder's signal by the antenna adequately. The harmonic radar system is one of the remarkable types of technology used in tracking and monitoring bee flight behavior in the field [13]. While monitoring by RFID generates limited information related to the bee entry and exit of the colony, the harmonic radar system provides detailed information on bee trajectories and foraging behavior. However, this system would require a clear line-of-sight at all times between the radar and the tracked object, and its transponders are not uniquely identified [13]. The user would have to determine which technique to use based on the nature of their experiment and the data expected to obtain. Despite providing valuable data on honey bee foraging behavior, previous studies used immobile RFID equipment fixed in on a single hive or location and relied on the availability of electric power. However, this study presents a compact 32-antenna RFID unit, which can monitor with high precision 32 honey bee colonies simultaneously, is easy to deploy, and is energy self-sufficient. In conclusion, our data show that the design and operation of this unit have met all the requirements needed for an RFID unit to monitor honey bees. This unit provided highly accurate data on ten colonies simultaneously, was self-sustained for months by solar energy, and required low wattage to operate. Thus, the RFID unit described in our study would be a valuable tool to facilitate and improve the use of RFID technology in honey bee and social insect studies. Our next step is to make this unit WIFI-enabled, which will allow remote access to the data by transmitting the latter from the field directly to a Cloud Platform. This has already been studied in more developed systems such as the Columbia River Salmon PIT tag program and the ETAG RFID Open Science System in Oklahoma for bird monitoring. The following are available online at [[https://www.mdpi.com/article/10.3390/asi4040088/s1](https://www.mdpi.com/article/10.3390/asi4040088/s1)]([https://www.mdpi.com/article/10.3390/asi4040088/s1](https://www.mdpi.com/article/10.3390/asi4040088/s1)), Figure S1: Process of scanning and renaming transponders using the RFID unit's computer. (a) The interface of the MultiReader software with scanned tags (red color). The display of blue dots indicates the active connection between the unit and software for both antennasand the reader. (b) Visualization of the new window for tag renaming prompted by right-clicking on the transponder's name (EPC Value). A confirmation message must be displayed to ensure proper name recording in the transponder's internal memory. Figure S2: Basic operation of the ItemTest software running on a laptop connected to the RFID unit. (a) Active connection of the unit to the software for data transfer and communication. (b) Results of tag inventory obtained by clicking the \"Play\" button (top left) to initiate tag scanning (highlighted in gray). (c) Final output generated by ItemTest as an excel file (_c_vs), which comprises the date and time of the bee activity (Timestamp), name of the bee (EPC), and its hive (Antenna). Figure S3: Interface of the preferred software for this unit (Speedway Connect).