Introduction

Our testing bee yard (apiary) is located near Dallas, Texas.  The data collection system is based on the R9 Safezone product.  The R9 system uses the LTE data network to gather and process sensor data in the cloud.  Below is a picture of the R9 smart frame.  One R9 SN400 sensor node is incorporated into a traditional “Langstroth” deep frame but can be easily moved to any frame size. The SN400 sensor node supports three temperature sensors, one humidity sensor and a tank level sensor. We place the smart frame in the lower brood box and locate it as one of the outside frames.

Hive Temperature

With three temperature probes, we can monitor several locations in the lower brood box, including inner frame brood temperature, as well as ambient brood box temperature. For this scenario, we will focus on these two items.

One of the most interesting behaviors exhibited by honey bees is their ability to precisely control the temperature of the hive (known as thermoregulation). Bees will congregate between the frames containing brood, and by using their flight muscles begin warming the brood. This is a colony wide behavior that involves the bees operating as a single cohesive organism. Based on our collected data, brood temperatures are typically maintained within 1^oF of 95F-96F.  It is this thermo-regulating behavior that makes temperature a particularly good indicator of hive health.  By monitoring temperature, the R9 system can begin to notify beekeepers when deviations occur.  The image below shows a typical brood temperature vs. ambient hive temperature.  A beehive that is properly thermoregulating is typically healthy and attempting to raise future generations of bees.

Of course, a simple hive monitoring system cannot replace a beekeeper.  Scheduled hive inspections are still required.  As hive monitoring systems evolve, and become more advanced, inspections will likely be less frequent, but not halted altogether.

 

A Collapsing Beehive

What does a collapsing hive look like from a temperature viewpoint, and how early can temperature be used to detect potential issues?  In the image shown below, hive collapse caused by failing thermo-regulation can be observed.  One characteristic of temperature data alone (with respect to hive collapse), is it tends to be a lagging indicator.  A queen-less hive will continue to maintain its brood temperature for a limited period of time.  This image/data suggests that monitoring brood temperature might provide a 3 to 5-day advanced warning of hive issues.  By incorporating measured brood temperatures with temperature alerts and charts, earlier detection of hive issues is possible.  In this case, a web-based temperature alarm could be set to indicate the onset of a potential problem.

 

What hive events might cause a loss of thermo-regulation and hive collapse?  Bee swarming (about half the bees leave the hive with the queen, and half stay to raise a new queen), a dead queen, or an unproductive queen can all cause this.  In all cases, the queen bee is involved, and requires the attention of a beekeeper.  In the case of this collapsing hive image above, immediate attention was not rendered.  A “wait and see” approach was used to find out more about the lack of thermo-regulation. This was a large hive that still had a substantial honey bee population.  The colony was continuing to forage for resources but was unable to successfully re-queen.  As a result, two frames of brood were taken from healthy hives and placed in the failing hive.  The below image shows an almost immediate resumption of thermoregulation in the presence of viable brood.

 

This collapse and thermo-regulation failure event occurred late in the year, which makes re-queening difficult due to a lack of available queen stock.  Had this event occurred earlier, the hive could have been immediately re-queened and thus the risk of complete collapse could be minimized.  This hive, with the addition of two brood frames was still unable to successfully raise a queen and recover.  For about 10 days the hive was observed, but no queen cell was produced.  As a result, the hive was merged with a queenright hive (a viable queened hive, as compared to a queen-less hive), to avoid a complete loss.  Based on the image of thermal regulation failure shown above, it is demonstrated that honey bee hive temperature is a useful metric for the management of beehives. It is an indicator of hive health, and with the addition of web server-based alarming, charting, and reporting, it is a useful tool for the management of large numbers of hives.

 

The R9 Hive Management Tool is a multi-hive wireless monitoring system that can be deployed in remote honey bee apiaries.  Each monitored hive (multiple hives can be monitored by one LTE gateway device) is outfitted with a single R9 smart frame.   Each smart frame provides:

• • • • Single temperature / humidity sensor to monitor ambient hive conditions.
      • Two inner frame brood temperature sensors.
      • Single tank level sensor for an internal sugar water feeder.

 

The smart frame is powered with two AAA alkaline batteries, which allows for approximately two years of continuous operation.  Each smart frame communicates to a centrally located G200 LTE gateway. The gateway collects data from each hive and transmits it to the R9 cloud-based monitoring station, every 15 minutes.  The G200 gateway can use a supplemental solar charging system that can be affixed to any standard T-Post, if wall power is not available at the installation site.  The R9 browser-based user dashboard provides historical charting, real-time text / email alerts, and both weekly and monthly reports for all monitored parameters.