American Scientist

As an insect ecologist, the driving force behind my career choices is to conserve insects and biodiversity, but I often feel like those who sound the call to “Save the bees!” are missing the point. Focusing on this tired cliché may actually result in public advocacy and policies that do not strategically help pollinators. In honor of National Pollinator Week, I’d like to add some nuance that seems to be missing from the conversation so far, particularly with regard to pollinators and pesticides.

1. Bees are the only pollinators.
   Much of the current discussion about pollinators has been focused on bees—and most of that on honeybees in particular. Yet honeybees (Apis mellifera) are just one species of more than 100,000 invertebrate species that pollinate plants. They include a wide range of taxa and life histories, from beetles to flies to moths. Additionally, there are over 1,000 vertebrate pollinators, including birds and bats. Honeybees are unique in their domestication, as they are bred and managed akin to cattle or hogs. Most other pollinators are wild populations. What they all have in common is their role in plant reproduction: transferring pollen grains to floral ovaries for fertilization. Not all plants require pollination, but it’s estimated that three-quarters of the global food supply depends on it. So, if we want to save pollinators to save the global food supply, we need to study and understand the contributions of all pollinators, not just honeybees.


2. Colony collapse disorder affects all pollinators.
   Colony collapse disorder—when the majority of worker bees disappear, leaving behind the rest of the hive—refers only to a narrowly defined set of symptoms. These symptoms have been found only in honeybee colonies thus far. Recent surveys indicate that wild pollinators such as bumble bees (Bombus spp.) are also declining, but we don’t know the population status of over half the known wild pollinators.
   
   Unfortunately, the focus on colony collapse disorder, while greatly improving our knowledge of honeybee health, has diverted resources that could be used to understand pollinators more broadly. Most other bee species are solitary, meaning they do not live socially in hives. It is unclear how the insights from colony collapse disorder research would apply to solitary bee or non-bee pollinator life histories.


3. Neonicotinoids are the cause of colony collapse disorder.
   Neonicotinoids are only part of the colony collapse story. Neonicotinoids are a class of insecticide, related to nicotine, which have recently become very widely used in agriculture and residential backyards. They block a neural pathway found mostly in insects, which causes paralysis and death. Neonicotinoids were initially touted for their reduced risk to beneficial insects and other nontarget organisms because of their selectivity. However, now a large body of research suggests that neonicotinoids are toxic to bees and potentially a causal factor in colony collapse disorder. There have been several high-profile incidents of neonicotinoid sprays causing massive bee kills in recent years. It’s crucial to note that these incidents were the result of misapplication or spray drift, not routine exposure. It’s illegal not to follow the application directions on the label of a pesticide, which stipulate not to apply neonicotinoids to plants when flowers are blooming or when bees might be foraging. In fact, due to public outcry, the U.S. Environmental Protection Agency (EPA) has revised labels to make directions for bee safety clearer and has created a portal to report bee kills.
   
   This is not to say that neonicotinoids do not have adverse effects on pollinators nor that they haven’t been linked to colony collapse disorder, but there are many other factors that are thought to be contributing to honeybee declines that banning neonicotinoids will not solve. These include pathogens, extreme winter weather, diseases, and diet quality. My next post will focus on the regulatory challenges to addressing the concerns of environmental advocacy groups about the role of neonicotinoids and other pesticides on pollinators.


4. Neonicotinoids are the only pesticides that hurt pollinators.
   The definition of the term pesticide is so broad that it is almost meaningless. Neonicotinoids are just one class of insecticide. There are herbicides, fungicides, acaricides, miticides, rodenticides, and more. Even antibacterial soap or antibiotics can be thought of as pesticides. Living organisms can be pesticides, too, such as sprays of Bt (Bacillus thuringiensis) approved as a form of organic pest control. So, it’s important to be specific when studying and discussing pesticides, because of the wide range of chemicals and creatures one could be referencing.
   
   Yet the diversity of pesticides and pollinators is not reflected in the focus of research on pesticides and pollinators. Neonicotinoids and their effects on honeybees have received the lion’s share of research and public debate. There is important work being done on other chemicals and taxa, though. For example, a recent experiment by Olivia Bernauer and her colleagues found that exposure of a native bumble bee (Bombus impatiens) to a common fungicide resulted in colonies with fewer workers, smaller queens, and overall lower biomass. This result is surprising in part because fungicides have been considered generally safe for bees. More research is needed to understand how pesticides, broadly defined, affect pollinators, broadly defined—not just bees.


5. Figuring out how to “save the bees” is easy.
   Pollinators have varied habitats and foraging behaviors, and the social structures and overwintering strategies of some pollinators are complex. This makes rigorous research on the effects of pesticides on pollinators hard to tease apart. There is no perfect method: Lab assays can examine acute toxicity but may not be using realistic doses or exposure pathways, while field experiments can examine season-long or multiyear patterns but may not be able to account for other sources of variation. This challenge is exemplified in an experiment by John Losey and colleagues that found detrimental effects of insecticidal Bt corn on monarch butterflies. The debated study’s findings were discredited a few years later, in large part because the approach in the lab setting did not match the real-life behaviors and potential routes of exposure of the monarch larvae.
   
   Appropriate doses and exposure pathways are critical for well-designed experiments on pesticides and pollinators. Just as important, it’s imperative not to mistake correlation for causation in observational studies. A 2014 study by Caspar Hallman and colleagues examining the effect of neonicotinoid use on farmland bird communities found that areas with more neonicotinoid found in surface water had fewer birds. This finding was widely reported as if the study had shown that the pesticide was killing birds through direct exposure. On the contrary, the correlative result, based on two separate data sets, is much more likely to be due to changes in the food web: Increased insecticide applications result in fewer herbivorous insects, which are the birds’ food source. Regardless, either explanation is speculation without investigation into the mechanisms.


6. Science will “save the bees.”
   Pollinators, both wild and managed, are undeniably in crisis and facing big changes in climate, land use, and policy globally that are likely to impact them. Rigorous field and laboratory research on pollinators is certainly a critical tool to addressing these challenges—but it should not be the only one. Pollinators need all the help they can get, so the scientific community should embrace partnerships with thinkers and dreamers in the social sciences, humanities, and arts to both imagine and then create different futures for bees and ourselves.
   
   For example, Heather Swan, a poet and literary studies scholar, has questioned how complex emotions affect honeybees and their human keepers. Similarly, Sainath Suryanarayanan, a classically trained entomologist who now works in partnership with sociologists, has questioned how the power structures related to expertise influence outcomes for policies about pesticides and pollinators. Successfully protecting pollinators may include entertaining ideas like these that may seem tangential to the simplistic “save the bees” mantra.
   
   For those who care about pollinator conservation, “Save the bees!” cannot be the only message, because it is now inextricably tied to honeybees and colony collapse disorder. I care about these issues deeply, but proposing solutions focused on honeybee decline ignores the needs and life histories of the majority of wild pollinators. Because public outcry helps shape science funding and policy, we end up with major holes in our scientific knowledge that could better inform pollinator protection, broadly defined. The attention might be on neonicotinoids and honeybees for now, but a broader research agenda could help inform how to sustain a diverse and healthy pollinator community. Ultimately, I do want to save the bees—and all the other pollinators too.