Monitoring colony phenology using within-day variability in continuous weight and temperature of honey bee hives

Authors: Meikle, William; Weiss, Milagra; Stilwell, Abby

Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2015
Publication Date: 5/16/2015
Publication URL: http://handle.nal.usda.gov/10113/60998
Citation: Meikle, W.G., Weiss, M., Stilwell, A.R. 2016. Monitoring colony phenology using within-day variability in continuous weight and temperature of honey bee hives. Apidologie 47:1-14. doi: 10.1007/s13592-015-0370-1.

Interpretive Summary: Monitoring the growth of a bee hive by weighing it is a well known method. Weighing the whole hive can provide information on rate of growth, but it does not provide information on how much each part of the colony, the adults, the brood or the food stores, is growing and changing. Weighing hives continuously, however, provides data on forager activity and forager success. We found that by dividing weight data into the long-term ( changes that lasted more than 1 day) and short-term (changes that lasted less than one day) parts, we could tell how much foraging was going on, and the amount of foraging was, not surprisingly, related to the amount of adult bees in the colony. Temperature management by honey bees is well known. We monitored hive temperature continuously as well, and analyzed the data the same way we analyzed the weight data. Because bees need to maintain constant temperatures for their brood, how much they let the temperature vary depends on how much brood; with lots of brood temperature varies little, but when brood is reduced or absent temperature can vary a lot. As a conclusion, we found that the amplitude of the within day weight changes was a good predictor of the weight of the adult bee population, and amplitude of the within day temperature changes was inversely related to the amount of brood. These measures would be helpful for monitoring colonies without disturbing them.

Technical Abstract: Continuous weight and temperature data were collected for honey bee hives in two locations in Arizona, and those data were evaluated with respect to separate measurements of hive phenology to develop methods for monitoring hives non-invasively. Both the weight and temperature data were divided into two parts: the 25 h running average and the daily within-day changes, or “detrended” data. Sine waves were fit to the detrended data, and data on adult bee and brood masses from hive evaluations were regressed on the amplitudes of those fit curves. Daily detrended weight amplitudes were significantly correlated with adult bee populations during nectar flows, and the relationship was validated using data gathered independently from France. The effects of an adult bee kill on detrended weight data were also contrasted with published data on hive weight changes after swarming. Amplitudes of detrended temperature data were found inversely correlated with the log of colony brood weight, and this was validated using data gathered independently from California. These analyses show that continuous data are rich sources of information about colony health and activity.