1 Looking to Nature to Solve the Health Crisis of Honey Bees
Robin W. Radcliffe1 and Thomas D. Seeley2
1 Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
2 Department of Neurobiology and Behavior, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, USA
* Illustrations by Anna Connington
Figure 1.1 Gathering honey, a beekeeping scene from the Tomb of Rekhmire. Egypt c. 1450 BCE (de Garis Davies 1930).
Prologue
Scientists recently discovered the lipid residues of ancient beeswax inside the earthen pottery vessels of Neolithic farmers, which suggests that the origin of domestication of honey bees dates back to the onset of agriculture (Roffet‐Salque et al. 2015). The long association between humans and bees (Figure 1.1), with mankind harnessing honey bees for food, medicine, and spiritual wellness, can be summed up in a single word: beekeeper. In this book, we introduce a new term to the English language: bee doctor. Etymologists, who study word metamorphosis, follow how the use of particular words gradually evolve in our language – e.g. from bee keeper, to bee‐keeper, and finally to beekeeper. Just as the “honey bee” is spelled as two separate words because it is a true bee, we will likewise separate “bee” and “doctor” since bee veterinarians are true doctors in every sense of the word. We work from single bee to whole colony, from individual cell to multicellular organism, and from microenvironment to ecosystem. Given the urgent call for modern Homo sapiens to reverse the anthropogenic impacts on pollinators everywhere, including our sacred Apis mellifera, we propose adoption of “bee doctor” without delay. Humans have been “keeping” bees for thousands of years, so we now have the word “beekeeper.” Only by forging a close connection between human beings and honey bees in all matters relating to their health, do we stand a chance to save one of earth's most industrious species – the one who gives us food, health, and happiness, and was idolized on the walls of Egyptian tombs. Perhaps someday we will even have the word “beedoctor.”
A Tenet of Medicine: Learn the Normal
Colonies of honey bees living in the wild are prospering in American forests even in the face of myriad stressors that are decimating the managed colonies living in apiaries. We know that both cohorts are exposed to the same parasites and pathogens. How then do wild colonies survive without beekeeper inputs, whereas managed colonies live just one to two seasons if humans do not intervene with various supplements or medicines? In examining this conundrum, we must ask ourselves as bee doctors, working hand‐in‐hand with beekeepers, how we should examine the health of the honey bee? A fundamental tenet of medicine is the need to learn what is normal (regarding anatomy, physiology, or the state of being known as health) before one can understand deviations from this baseline. We contend that the “normal” that bee veterinarians should be concerned about is the wonderfully adapted lifestyle of wild colonies of honey bees. In this chapter, we will highlight the important differences between wild and managed colonies of honey bees and we will suggest ways health professionals can make use of the marvelous tools for health and survival that evolution has bestowed upon Apis mellifera through adaptation and natural selection.
Declines of the world's pollinators are happening at an alarming rate, and it is predicted that these declines will have adverse impacts on pollinator‐sensitive commodities worth billions of dollars (Morse and Calderone 2000). The threat to the honey bee is perhaps the best understood of the pollinator declines. Its causes are diverse: widespread use of agrochemicals, loss of plant and floral diversity, invasive species, migratory beekeeping practices, and monoculture pollen sources. Furthermore, the stresses created by these environmental stressors are intensified by the honey bee's pests, parasites, and pathogens. Although no single disease agent has been identified as the cause of honey bee colony collapse, pests and pathogens are recognized as the primary drivers of the massive deaths of managed bee colonies worldwide. Many of these agents of disease are vectored by an ectoparasitic mite introduced from Asia, Varroa destructor (Ellis et al. 2010; Ratnieks and Carreck 2010).
Investigations of honey bee declines have focused primarily on the pathogens themselves and their interactions, which are now understood to be multifactorial (vanEngelsdorp et al. 2009; Becher et al. 2013; Di Prisco et al. 2016). Besides the pathogens, the environments in which honey bees live also profoundly impact colony survival. In this chapter, we will examine honey bee health and the alarming levels of colony mortality from an ecological and evolutionary perspective. We will embrace the logic of natural selection and we will learn important lessons from long‐term studies of honey bee colonies living in nature (Brosi et al. 2017; Seeley 2017b, 2019a; Neumann and Blacquière 2016).
Good Genes Versus Good Lifestyle: The Varroa Story
We will begin our account of the health and fitness of wild colonies by relating the story of the Varroa mite (V. destructor), a parasite that switched hosts from the Eastern honey bee (Apis cerana) to the Western honey bee (A. mellifera). In order to understand the resistance to Varroa mites that is found in wild honey bee colonies, we must examine more deeply their genes and their lifestyle.
Beekeepers today rely primarily on commercial queen producers for their bee stock. Most hobby beekeepers, for example, will start an apiary or add colonies to an apiary by purchasing either a “package” of bees shipped in a cage or a nucleus colony (“nuc”) living in a small hive. In North America, packaged bees are shipped from various southern states in the U.S., as well as from California, and Hawaii, so they consist of stock that is not necessarily adapted to the beekeeper's local climate, temperatures, and agents of disease. Furthermore, even though queen bees are also produced and sold across North America – their genetics often traces to just a handful of colony lines. In many places, good colony health can be fostered by the use of locally‐adapted bees.
From an evolutionary perspective, the observation that wild colonies have rapidly adapted to the Varroa mite, and to the diseases they vector, over a remarkably short timeframe (ca. 10 years), suggests that surviving wild colonies have either good genes (DNA), a good lifestyle, or both (Seeley 2017a).
Good Genes
The Varroa mite is the leading cause of honey bee health problems on all beekeeping‐friendly continents except Australia. Beekeepers have always experienced colony losses, but it was not until the arrival of this parasitic mite that colony die‐offs became severe in North America. The Varroa mite lies at the heart of poor colony health, because it acts both as a primary stressor (the adult mites feed on the “fat bodies” of adult bees and the immature mites feed on immature bees [pupae]) and as a vector for a myriad of the viral diseases of honey bees (vanEngelsdorp et al. 2009; Martin et al. 2012). If a managed colony of honey bees is left untreated, Varroa mites will kill it within two to three years (Rosenkranz et al. 2010). Remarkably, the wild colonies living in the forests of North America today, plus some notable examples of European honey bees living on islands, are resistant to the mite (De Jong and Soares 1997; Rinderer et al. 2001; Fries et al. 2006; Le Conte et al. 2007; Oddie et al. 2017). How did this resistance evolve? We know that wild colonies in the northeastern forests of North America went through a precipitous
