Potential for probiotics to mitigate environmental stress in Western honey bees
Abstract
The use of probiotics, particularly strains of lactobacilli, presents a promising strategy for addressing key threats to Apis mellifera, such as Varroa mites and Paenibacillus larvae. Lactobacilli are part of the honey bee hindgut microbiota, and some probiotic strains have been shown to enhance host immunity and buffer against pathogens. In addition, certain Lactobacillus strains can inhibit P. larvae growth, potentially preventing outbreaks. There is also some evidence that lactobacilli increase resistance against Varroa mites through immune system modulation or hive environment alteration. The objectives of this thesis were to: (1) review the complex interactions between P. larvae and other microorganisms within the bee gut microbiota; (2) perform an empirical study delivering probiotics to honey bee colonies across diverse landscapes. The field study revealed that oral administration of LX3 via protein patties significantly reduces mite infestations relative to a no-LX3 patty control across all environments, whereas topical spray applications do not yield the same success. This approach could serve as an environmentally friendly, sustainable method to improve bee health, crucial for maintaining ecological balance and supporting global agriculture.