|Holst, Niels - DANISH INST AGR|
|Mercadier, Guy - USDA-ARS-EBCL|
|Derouane, Franck - USDA-ARS-EBCL|
Submitted to: Journal of Apicultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 16, 2006
Publication Date: March 20, 2006
Citation: Meikle, W.G., Holst, N., Mercadier, G., Derouane, F., James, R.R. 2006. Using Balances Linked to Dataloggers to Monitor Honeybee Colonies. Journal of Apicultural Research and Bee World 45(1):39-41. Interpretive Summary: 1. Problem. Honeybees play a very important role in agriculture, and many scientists are trying to develop ways to help them by controlling diseases and parasites. In order to test different methods, they conduct field experiments on beehives, and need data on the population size, health and weight of beehives. However, bees dislike being disturbed often, and colonies that are visited too frequently can become weak and, in some cases, may even leave the hive. Furthermore, if the hives are not visited, then the amount of data resulting from the experiment is lower. The question we asked was: is there a way to get data on the activity and size of a bee colony without bothering the colony? 2. Approach. One technique that beekeepers often use is to measure the weight of beehives using outdoor scales. By measuring the weight every day, beekeepers can observe when the bees collect lots of nectar. If the colony weight goes down, that might indicate a problem with the bees. We expanded on that approach using electronic balances linked to dataloggers and measured colony weight every hour for several months. During that period we observed weight changes associated with nectar foraging, and with rainfall. 3. Results. We found that the electronic balances provide a lot of different kinds of data, and that those data may be useful in measuring the effects of experimental treatments. We observed the effects of daily nectar collection, foraging activity and rainfall on hive weights. We think this technique might be helpful to bee scientists because they might be able to get more data out of the same field experiments.
Technical Abstract: Honeybee colonies are sensitive to frequent disturbance, which may cause overly defensive behavior, absconding, or a weakening of the hive. For this reason, non-invasive ways of monitoring hive health would be useful when frequent data from beehives, such as during field experiments, are needed. At the European Biological Control Laboratory, the weights of two beehives were recorded hourly using electronic balances linked to dataloggers. Although the two hives were established in close proximity and at the same time, the weights of the two colonies differed markedly over the course of the experiment from 15 June to 30 September. The parameters examined were: 1) colony weight (the total hive weight less the beehive structure, e.g. the brood box, frames, lid, etc.); 2) daily weight trends between the two hives; 3) adult bee population ratios between the two hives; and 4) an analysis of the impact of rainfall on hive weights. To control for the effects of weather and background variation due to factors other than the bee colony, the weights of empty hives on the scales were also monitored. The scales provided data on colony growth and activity, and may be useful in extracting more information from field experiments involving bee colonies.