Nutritive and immunological benefits derived from the honey bee gut microbiome are threatened by anthropogenic stressors

Insect gut microbes have a disproportionate effect on their hosts, including the honey bee, Apis mellifera L. The honey bee gut, and that of other species that have been investigated, harbours a specific gut community that is conserved across populations globally. However, this gut community changes between different castes, sexes and life stages, which is largely due to diet and gut physiology. Evidence suggests that a healthy gut community is essential for honey bees to maintain functional immunity and nutrition. Without the four important gut symbionts (Lactobacillus, Bifidobacterium, Snodgrassella alvi and Gilliamella apicola), honey bees lack the ability to gain sufficient nutrients, protect themselves against pathogens and prevent intoxication. Unfortunately, honey bee gut symbionts are under threat due to in- hive pesticides, antibiotics and climate change. Therefore, we discourage the overuse of antibiotics and in-hive pesticides, as they could have unforeseen consequences for the honey bee gut microbiota. Instead, we recommend that beekeepers and scientists explore alternative options, such as bolstering honey bee resilience through probiotics.