Reduced density and visually complex apiaries reduce parasite load and promote honey production and overwintering survival in honey bees

Abstract

Managed honey bee ( Apis mellifera ) colonies are kept at much greater densities than naturally occurring feral or wild colonies, which may have detrimental effects on colony health and survival, disease spread, and drifting behavior (bee movement between natal and non-natal colonies). We assessed the effects of a straightforward apiary management intervention (altering the density and visual appearance of colonies) on colony health. Specifically, we established three “high density / high drift” (“HD”) and three “low density / low drift” (“LD”) apiary configurations, each consisting of eight bee colonies. Hives in the HD apiary configuration were of the same color and placed 1m apart in a single linear array, while hives in the LD apiary configuration were placed 10m apart at different heights, facing outwards in a circle, and made visually distinctive with colors and symbols to reduce accidental drift between colonies. We investigated disease transmission and dynamics between the apiary configurations by clearing all colonies of the parasitic mite Varroa destructor , and subsequently inoculating two randomly-chosen colonies per apiary with controlled mite doses. We monitored the colonies for two years and found that the LD apiary configuration had significantly greater honey production and reduced overwinter mortality. Inoculation and apiary management intervention interacted to affect brood mite levels, with the highest levels in the inoculated colonies in the HD configuration. Finally, foragers were more than three times more likely to drift in the HD apiary configurations. Our results suggest that a relatively straightforward management change–placing colonies in low-density visually complex circles rather than high-density visually similar linear arrays–can provide meaningful benefits to the health and productivity of managed honey bee colonies.

Summer weather conditions influence winter survival of honey bees (Apis mellifera) in the northeastern United States

“…Queen age and quality can also influence winter survival 11 Moreover, the methods used for controlling Varroa populations, the timing of application and the conditions of application (including weather conditions) can influence winter survival 65 . Even the relative distribution of the colonies within the apiary can influence survival, likely by influencing disease dynamics: colonies in “low density” apiaries had higher winter survival than colonies in “high density” apiaries 66 . Finally, the survey did not include information about levels of or evidence for parasites or pathogens, and thus we could not evaluate whether these parameters correlated with survival.…”

American foulbrood in a honeybee colony: spore-symptom relationship and feedbacks between disease and colony development

“…The experiment was originally designed to test the efficacy of a commercial honeybee specific lactic acid bacteria preparation against AFB relative to two negative controls (a placebo preparation and a no treatment control) and a positive control (the antibiotic Tylosin) (Additional file 3, [67]). The colonies were arranged in four rows of ten colonies each, with 1.5 m distance between individual colonies in each row and 1.5 m distance between rows and all entrances facing the same direction [68]. All colonies were experimentally inoculated with the same dose of Paenibacillus larvae spores at to precipitate AFB epidemics with the four treatment groups distributed randomly among the 40 colonies.…”

Industrial bees: The impact of apicultural intensification on local disease prevalence

“…Links between drift-mediated pathogen transmission and colony numbers have been documented for a variety of pathogens (Seeley & Smith, 2015)-including brood specialized and non-specialized, micro-and macro-parasites (Belloy et al, 2007;Budge et al, 2010;Dynes et al, 2017;Nolan & Delaplane, 2017). Larger numbers of colonies per apiary are a driver of higher drift (Currie & Jay, 1991), as are changes in apiary arrangement (Dynes et al, 2019;Jay, 1966). While beekeepers typically maintain equal distances between their colonies regardless of how many colonies are in the apiary (such that larger apiaries have a bigger area footprint), our approach of increasing between-colony transmission in larger apiaries would also capture any additional transmission from spatial crowding.…”

“…We generalize colony arrangements to three unique configurations drawn from experience, classic apicultural literature (Jay, 1966) and current experimental work (Dynes, Berry, Delaplane, Brosi, & de Roode, 2019): array, circular and lattice ( Figure 1). We restrict between-colony pathogen transmission to nearest neighbours (see discussion), those in closest proximity to each other (connected by an arrow in Figure 2).…”