photo: barta iv
“The use of power is a tremendous responsibility and must be done without arrogance and with a subtle sensitivity, if not a reverence, for the value of all life.” — Robert Rabb
At last month’s meeting, we marveled over the mechanisms of the honeybee hive: how they find and communicate food sources through the waggle dance; prepare the queen for swarming when food stores have reached a lethargic high; and find and measure their prospective new homes. We debated the merits of comparing honeybee and human decision-making processes—whether there’s any truth to Thomas Seeley’s claim that humans can or should learn borrow democratic techniques from the honeybees’ methods, given the complexity of human needs.
This month, the philosophical implications of our studies broached a perhaps even more complicated subject: Is it ethical to kill insects in the name of scientific study? In Honeybee Democracy, Seeley matter-of-factly describes killing whole hives of bees during his experiments on Appledore Island and throughout his career. It is hard to imagine how he might have come about his significant discoveries without this method: To study a swarm’s chosen hive in trees, for example, he spooned cyanide into the active hive, then felled the tree and examined the hive and its population in detail. Such work led to breakthroughs in the criteria by which bees choose their homes, as well as information about how such homes are found and advertised to the swarm by scout bees. It is difficult to imagine an equally effective method for studying such small and lively insects, much less when they number in the tens of thousands in a single hive.
There are scientists exploring the question, however. In his 1988 essay “Not to Harm a Fly: Our Ethical Obligation to Insects,” Jeffrey Lockwood cites honeybees in particular as a compelling argument that insects possess some form of sentience, which—along with the ability to experience pain—is the common criteria for the granting of the right to ethical (pain-minimalizing) treatment. While he ultimately comes to the conclusion that the killing of insects may, in many cases, perform a biological need for the human race (by improving our ability to harvest food, for example), he does offer a base for a moral framework in working with insects: “We ought to refrain from actions which may be reasonably expected to kill or cause nontrivial pain in insects when avoiding these actions has no, or only trivial, costs to our own welfare.”
Lockwood also cites the use of anesthetics when examining insect biology as “ethically mandatory” unless the use of anesthetics severely hinders the work (and there is no alternative method of study). How and when insects experience pain is an ongoing question, but Lockwood argues that “if some insects are found to be totally lacking in sentient capacities, we will have committed no wrongs to have acted in an overly humane fashion. Surely it is preferable to err on the side of moral consideration than on the side of moral exclusion.”
It’s a question that we beekeepers will face ourselves this month, as we check our hives for varroa mites and consider the future of any infested hives. This year we chose bee packages from a local beek in NY state who raises mite-and-winter hardy bees, but we’ve seen high mite counts in at least one of our hives, and if treatment doesn’t prove effective, we will have to consider Randy Oliver’s argument in American Bee Journal’s Varroa Management series that protecting healthy hives going into winter may require eliminating mite-heavy hives that are unlikely to survive, but highly likely to spread their infestation to healthy hives.
Regardless of the ethics of his methods, it’s undoubtable that Seeley and his partners made extraordinary breakthroughs in the science of the swarm and how it chooses a new home. Here are a few facts to fascinate this month:
• Scout bees are forager bees (which are already the oldest bees in the hive) who, when they sense that the colony has plenty of food stores, recognize that the hive is about to swarm and change jobs (132). This switch may be triggered by sheer abundance of food—foragers whose bellies have been full for several days are likely to become scouts—or it may be connected to simple inactivity caused by lack of food-storage space in the hive (140).
• However, not every forager becomes a scout. Worker bees only live 3-5 weeks during the summer months (131), so many generations pass before any bees make the switch. Further, the scout bee occupation is at least partially genetic (137).
• Swarms choose their homes only after scout bees have reported multiple inspected sites (144). There are at least six categories for choosing a site: cavity volume (ideally, 40 liters); entrance height, size, and direction; distance to entrance from the cavity floor; and the presence of combs from an earlier colony.
• The strength of a scout bee’s dance indicates its enthusiasm for the site, just as a forager’s dance indicates the strength of the pollen source. A “stronger” dance means both a livelier dance and more circuits through the hive (and therefore a longer dance). In most instances, the initial scout to a site performs the strongest dances; a scout who has been recruited is less likely to dance for the site (184).
• Scout bees do not choose desirable sites based on comparison. When they find a usable site, they report it; they do not find then visit other sites to compare to their findings. The knowledge of an ideal site is instinctual. In tandem, other scout bees are recruited almost randomly; stronger dances last longer and spread across the hive faster, so those are more likely to gain recruits, but a bee who encounters a weaker dance will visit and then may advertise for that site without considering alternatives (184). In other words, “they do not selectively follow dances for certain sites but instead follow dances at random” (190).
• So how do swarms come to consensus if, say, 30% of the hive is advertising for one site, and 70% is advertising for another? There is a rate of decline in advertisement. After a certain amount of time—a longer amount for more enthusiastic reports—scout bees go silent. More suitable sites, which have been more enthusiastically advertised, will naturally have recruited more bees through exposure. Eventually, the site with stronger advertisement wins as fewer and fewer bees dance.
• Additionally, new research—also by Thomas Seeley and associates—suggests that when a hive is dangerously near a deadlock decision, scout bees may take breaks from dancing to interrupt other bees’ dancings by head-butting and emitting a high-pitched beep.
• So essentially: Forager bees turn in scout bees. Scout bees roam until they find a suitable site. They return to the hive to dance for it; then return to the site, inspect it for a shorter amount of time, and again return to the hive to dance for it. After several circuits of this, the initial scout bees stop dancing; by this point, other scout bees are doing their own scouting and recruiting. When a very good site has been found, advertised, and recruited by several scouts, the number of dances for that site will grow until the bees are nearly unanimously dancing for this site alone, and the swarm takes off.
At our next meeting, we will conclude our reading of Honeybee Democracy as Seeley makes his final arguments for the “swarm as cognitive entity,” as the title of Chapter Nine suggests. Perhaps there we will find further insights into the troubling question of ethical insect study.
Lockwood, Jeffery. “Not to Harm a Fly: Our Ethical Obligation to Insects.” Between the Species 4, no. 3 (1988): 204-211. http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1712&context=bts&sei-redir=1&referer=h
Seeley, Thomas. Honeybee Democracy. Princeton, NJ: Princeton University Press, 2010.
Seeley, Thomas, P.K. Visscher, T. Schlegel, P.M. Hogan, N.R. Franks, J.A. Marshall. “Stop signals provide cross inhibition in collective decision-making by honeybee swarms.” Science (2012): 108-111.
Zimmer, Carl. “The Secret Life of Bees: The World’s Leading Expert on Bee Behavior Discovers the Secrets of Decision-Making in a Swarm.” Smithsonian Magazine, March 2012, https://www.smithsonianmag.com/science-nature/the-secret-life-of-bees-99559587/.