Using temperature monitoring to know the status of your Queen.
Brood nest temperature is of extreme importance to the colony and is controlled with utmost precision by the bees. This brood temperature regulation is called homeostasis. Honey bees maintain the temperature of the brood nest between 34°C and 35°C so that the brood develops normally. When the temperature in the nest is too high the bees ventilate by fanning the hot air out of the nest (which evaporates water) and sometimes even partially evacuate the nest.
Homeostasis can be used as a measure of colony fitness. More genetically diverse colonies (stemming from a higher number of different patrilines) are better at thermoregulation.
If the brood temperature becomes unstable, it starts to vary or drop – this shows that the bees may have stopped thermoregulating the brood area and the colony is queenless.
The Arnia in-hive sensor has a built-in temperature sensor which takes temperature readings from inside the hive every 4 hours. The latest sensor sits on top of the brood frames which gives many benefits over the previous sensor that sat directly inside the brood nest. The sensor being on top of the frames gives a better indication of brood nest size and thus colony strength. As the temperature fluctuates with that of the ambient temperature, it is positively offset by the amount of heat generated by the bees regulating the brood nest. This will give a slightly unstable temperature reading, but how much offset is achieved is an indicator of colony strength. In the UK If the colony is large and strong, the sensor will pick up a more stable brood temperature at anywhere between 28 and 35 degrees C. A weaker colony with brood will give a in-hive temperature reading of between 21 and 32 degrees C. A brood-less or queen-less colony will see the in-hive temperature mirror the ambient temperature.
The graph below shows the brood temperature life cycle from the end of summer, through autumn, winter, spring and start of summer the next year.
There are several possible causes for very unstable brood temperature:
- the queen has stopped laying
- the colony is queenless
- the queen is above the queen excluder
- the brood nest has shifted or reduced significantly in size.
If your hive has recently swarmed and you are waiting on your new virgin queen to mate and start laying again there can be an overwhelming urge to go and check. This can be detrimental to the colony if you accidentally squash this queen or interfere with her leaving, or coming back from, her mating flight. Using an Arnia in-hive sensor and monitoring brood nest temperature during this critical period can help you determine without opening up the hive if the new queen has successfully started to lay.
The graph below shows a colony successfully coming out of winter. A newly mated queen starting to lay would show a similar graph trend.
If you'd like to start monitoring your hives, you can view all of our latest products and prices at arnia.co/shop, or drop us an email at sales@arnia.co.uk.