|MAES, PATRICK - University Of Arizona
|FITZ, WILLIAM - University Of Arizona
Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2017
Publication Date: 5/17/2017
Citation: Meikle, W.G., Weiss, M., Maes, P., Fitz, W., Sheehan, T.H., Snyder, L.A., Mott, B.M., Anderson, K.E. 2017. Internal hive temperature as a means of monitoring honey bee colony health in a migratory beekeeping operation before and during winter. Apidologie. 48:666-680. https://doi: 10.1007/s13592-017-0512-8.
Interpretive Summary: Because honey bees must forage for nectar and pollen, and will collect those in both agricultural and natural landscapes, they are often exposed to many different kinds of stresses. Commercial honey bee colonies are often moved great distances to take advantage of commercial pollination opportunities and honey production. In the first year of this study, we kept track of four groups of bee colonies throughout the year as they moved from commercial or natural pollination to their winter quarters, and we measured pesticide contamination and levels of diseases and pests. Just before the hives were placed in a warehouse for overwintering, we evaluated the hives to determine how big the colonies were, how much brood they had, and we placed temperature sensors in some of the hives. After overwintering we evaluated the colonies the same way and analyzed the temperature data. We did the same the second year, but all the hives did not follow the same migratory path so we compared those that did follow the same path. We found that bee colonies differed with respect to the incidence of Nosema (a major bee disease) but not Varroa (a major bee pest) in one year but not the next. The first year the amount of capped brood was not different before overwintering but it was very different afterward, with colonies that spent most of their time in natural areas producing far more brood than those that spent time in or near commercial agriculture. Temperature data from the sensors easily distinguished the treatment groups the first year, especially during and after the time in the warehouse, with bee colonies that spent time in more natural areas having higher average temperatures. However, the second year colonies were more different before winter than after. We did find chlorpyrifos, a pesticide known to affect bees, especially in the second year. Overall the study showed that the kind of landscapes that bee colonies are exposed to play a large role in how colonies survive the winter, and continuously temperature monitoring is a useful tool to reveal treatment effects.
Technical Abstract: Internal temperatures of honey bee hives kept at different sites in North Dakota were monitored before and during winter to evaluate the effects of treatment, in the form of exposure to commercial pollination, and location on colony health. In October, hives exposed to commercial pollination during the summer had fewer adult bees and less brood than hives kept near natural forage, as well as lower average temperatures throughout winter. Within-day temperature variability was higher among hives exposed to commercial agriculture than for those kept near natural forage, indicating reduced temperature control. Fungicides, insecticides, varroacides and an herbicide were detected in bee bread and wax samples; no major differences were observed either in the diversity or concentrations of agrochemicals with the exception of chlorpyrifos at one site. Varroa and Nosema densities were low overall. Data from the same site used in successive years showed significantly more brood the first year, as well as lower temperature variability; high levels of chlopyrifos were detected in bee bread of colonies in the second year. Colony average temperature and temperature variability were informative with respect to colony phenology and postwinter status.