Bee Stressors from an Immunological Perspective and Strategies to Improve Bee Health

Abstract

Honeybees are the most prevalent insect pollinator species; they pollinate a wide range of crops. Colony collapse disorder (CCD), which is caused by a variety of biotic and abiotic factors, incurs high economic/ecological loss. Despite extensive research to identify and study the various ecological stressors such as microbial infections, exposure to pesticides, loss of habitat, and improper beekeeping practices that are claimed to cause these declines, the deep understanding of the observed losses of these important insects is still missing. Honeybees have an innate immune system, which includes physical barriers and cellular and humeral responses to defend against pathogens and parasites. Exposure to various stressors may affect this system and the health of individual bees and colonies. This review summarizes and discusses the composition of the honeybee immune system and the consequences of exposure to stressors, individually or in combinations, on honeybee immune competence. In addition, we discuss the relationship between bee nutrition and immunity. Nutrition and phytochemicals were highlighted as the factors with a high impact on honeybee immunity.

Developing Strategies to Help Bee Colony Resilience in Changing Environments

“…Many stress factors have been proposed and can be physical, chemical, nutritional, microbiological, and psychosocial. Stress may be generated by the perception of danger, a pathogen or parasite attack, nutrient deficiency, malnutrition, metabolic imbalance, microbiota disruption, or dysfunctional metabolic homeostasis induced by physical challenges: climate change, heat, cold, drought, and toxins (e.g., pesticides, antibiotics, heavy metals, air pollution, nanoparticles, plastics) ( Figure 2 ) [ 9 , 11 , 13 , 14 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 24 , 27 , 28 , 29 , 30 , 39 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. Based on the current evidence showing that honeybees and colonies are under the influence of numerous factors, a key question is: Could unravelling all those complex interactions allow the scientific community to set strategies that would help beekeepers reduce the loss of colonies ?…”

“…Nowadays, epigenetic and nutrigenomic studies show the importance of interactions between nutrition (diversity and quality), microbiota, climate, toxins, pathogens, and the resilience of a honeybee colony facing environmental changes ( Figure 1 ) [ 8 , 11 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Among the key factors, data show specific relations between bee immunosuppression and the combined effects of malnutrition (we still have to define what is adequate nutrition), parasites, microbial pathogens (bacteria and/or viruses), pesticide exposure from agriculture or even beekeeping, poor environments, human-modified environments, monofloral intensive agriculture, and stress linked to cold or drought [ 14 , 22 , 24 , 39 ].…”

Royal Jelly: Beneficial Properties and Synergistic Effects with Chemotherapeutic Drugs with Particular Emphasis in Anticancer Strategies

“…In this review, we will focus on the synergistic interactions between RJ and commonly used cancer drugs as part of our ongoing projects about honeybees and bee products [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

Insights into the Role of Natural Products in the Control of the Honey Bee Gut Parasite (Nosema spp.)

“…They play a critical role as pollinators of agricultural crops, wild flora, and natural vegetation, and are an effective biological monitor of environmental contaminants, acting as collectors for airborne particulates and dust deposited on the surfaces on which they land. Honey bees are also source of honey, royal jelly, propolis, bee pollen, bee bread, venom, and wax [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ].…”