Using a Data Logger to Record the Temperature Inside a Beehive

Forrest M. Mims III

Over the years I've done some consulting for the people at Onset Computer Corporation, the makers of Hobo Data Loggers and various related products. Consequently, I've accumulated a nice collection of wonderful little data loggers that I put to work whenever an opportunity arises. The result has ranged from learning the temperature inside a doghouse on a cold winter night to discovering that cumulus clouds can increase solar ultraviolet radiation on the ground by as much as 20 percent, a finding that became a short paper in a major science journal (F. M. Mims III and John E. Frederick, Cumulus Clouds and UV-B, Nature 371, 291, 1994).

My latest Hobo adventure occurred during a recent ice storm.

Last summer honeybees moved into a wood duck nest box on our creek. So I was curious about their status during the recent ice storm. First, I carefully placed a camera in front of the circular opening in the nest box and snapped several flash photographs. It was nearly freezing, and this did not seem to annoy the bees. The photographs showed that the bees were alive and well (see Fig. 1).

Figure 1. These honeybees stayed quite warm during a 3-day ice storm when the outside temperature was near freezing. Photograph by Forrest M. Mims III.

Next, I pointed a non-contact, infrared thermometer inside the next box opening. This indicated temperatures as high as 20.6 C (69 F) inside the box, but this seemed much too high, even according to a few scientific papers I found.

To find out more, an Onset U12-012 data logger with an external temperature sensor was placed in a thick sandwich bag and carefully mounted behind the wood duck nest box. Besides a port for the external sensor probe, the U120-012 monitors temperature, relative humidity, light and battery voltage. Logging intervals and channels to be monitored are selected through simple software.

The external sensor probe was inserted between two honey combs inside the hive when the outside temperature was around 1.7 C (35 F). This upset the bees, many of whom gathered at the opening. A dozen or more flew outside the opening and headed my way, and most soon fell out of the air due to the near-freezing temperature. But some began buzzing around my face, so I fled the scene. (Back in the house a few hours later, one who had hitched a ride in my hat suddenly started buzzing around my face!)

Several days later the temperature exceeded 4.5 C (40 F), so I retrieved the data logger and was surprised to find that the temperature inside the wood duck nest box ranged from 12.6 to 27.6 C (54.7 to 81.6 F)! The average temperature was an impressive 18.6 C (65.5 F), which is slightly warmer than the thermostat setting in our house. Because the outside temperature stayed around 1.7 C (35 F) or below during the entire period due to the warming effect of the adjacent creek, the ability of the bees to stay so warm is quite impressive.

Figure 2. Temperature during a 3-day ice storm recorded by an Onset U12-012 data logger inside the bee hive shown in Fig. 1. The red trace is the temperature inside the hive and the blue trace is the temperature inside the data logger just outside the hive. The yellow trace indicates the sunlight falling on the data logger, which was mounted between the wood duck nest box and the tree to which it is attached.

Various papers explain how honeybees can cluster together and warm up by shivering their wing muscles while being insulated by an outer layer of bees.

Here is an interesting article I found on the use of data loggers to monitor temperature inside a beehive: Naomi M. Saville, S.N. Upadhaya, A.N. Shukla and Sushil Pradhan, "Effect of hive design on internal hive temperature: a new application of temperature data loggers"

Honeybees can cool their hives on hot summer days, and I hope to learn more about this during the coming summer. If you decide to join me in these honeybee experiments, please use caution. All honeybees will defend their hives, and Africanized bees are especially dangerous.