Colony Level Prevalence and Intensity of Nosema ceranae in Honey Bees (Apis mellifera L.)

Abstract

Nosema ceranae is a widely prevalent microsporidian parasite in the western honey bee. There is considerable uncertainty regarding infection dynamics of this important pathogen in honey bee colonies. Understanding the infection dynamics at the colony level may aid in development of a reliable sampling protocol for N. ceranae diagnosis, and provide insights into efficient treatment strategies. The primary objective of this study was to characterize the prevalence (proportion of the sampled bees found infected) and intensity (number of spores per bee) of N. ceranae infection in bees from various age cohorts in a colony. We examined N. ceranae infection in both overwintered colonies that were naturally infected with N. ceranae and in quadruple cohort nucleus colonies that were established and artificially inoculated with N. ceranae. We also examined and quantified effects of N. ceranae infection on hypopharyngeal gland protein content and gut pH. There was no correlation between the prevalence and intensity of N. ceranae infection in composite samples (pooled bee samples used for analysis). Our results indicated that the prevalence and intensity of N. ceranae infection is significantly influenced by honey bee age. The N. ceranae infection prevalence values from composite samples of background bees (unmarked bees collected from four different locations in a colony) were not significantly different from those pertaining to marked-bee age cohorts specific to each sampling date. The foraging-aged bees had a higher prevalence of N. ceranae infection when compared to nurse-aged bees. N. ceranae did not have a significant effect on hypopharyngeal gland protein content. Further, there was no significant difference in mean gut pH of N. ceranae infected bees and non-infected bees. This study provides comprehensive insights into N. ceranae infection dynamics at the colony level, and also demonstrates the effects of N. ceranae infection on hypopharyngeal gland protein content and midgut pH.

Nosema ceranae disease of the honey bee (Apis mellifera)

“…Although all age groups had the same duration of exposure, workers infected at an older age had higher spore loads yet were more likely to survive infection despite having a lower ability to mount an immune response (Roberts and Hughes 2014). This finding can be applied to explore infection dynamics at the colony level where older workers are more likely to be infected than younger workers (Jack et al 2016).…”

Longitudinal Effects of Supplemental Forage on the Honey Bee (Apis mellifera) Microbiota and Inter- and Intra-Colony Variability

“…However, somewhat surprisingly, there can be more variability between the gut microbes in sisters of the same colony than between colonies. This can potentially confound the results of experiments and result in confusing or misleading interpretation of data, as many culture-independent 16S rRNA gene sequencing studies of the microbial community of honey bees also pool multiple colonial sister samples together [10,52,[59][60][61]. Possible sources of this variation could include paternal diversity through queens laying eggs fathered by multiple males [62], foragers drifting between colonies or variation in the ages of bees sampled, as we could not always collect foragers with corbiculate pollen.…”

A novel TaqMan ® assay for Nosema ceranae quantification in honey bee, based on the protein coding gene Hsp70

“…Nosemosis caused by Nosema apis (Zander, 1909) has been the only known microsporidiosis of honey bees (Klee et al 2007;Paxton et al 2007) until the first evidence of infection by Nosema ceranae (Fries et al 1996) in Apis ceranae. Being detected in Apis mellifera (Higes et al 2006), N. ceranae is now another widespread causative agent of nosemosis in the western honey bee (Ansari et al 2017;Chen et al 2009;Giersch et al 2009;Higes et al 2009b;Jack et al 2016). The consequences of nosemosis are of increasing concern among both beekeepers and scientists, although the actual impact of this exotic parasite on A. mellifera is still debated (Botías et al 2013).…”