New study finds Honeybees live half as long as they did 50 years ago

Honeyland is a 2019 documentary made by Macedonian filmmakers Tamara Kotevska and Ljubomir Stefanov. It follows the daily life of Hatidže Muratova, a beekeeper living in the mountain village of Bekirlija in North Macedonia and provides a brief look into humanity’s contemporary relationship with bees.

That relationship has been present and evolving for something like 10,000 years, according to archaeological evidence from all over the world. A cave painting inside the Cueva de la Araña — Cave of the Spider — near Valencia, Spain depicts a man climbing a tree to gather honey from a wild hive. It dates to about 8,000 years ago. Additionally, scientists have uncovered evidence of beeswax in pottery from Europe, the Near East, and Africa, all dating to about 9,000 years ago. There’s also evidence of domestication, meaning managed or artificial hives, going back about 7,000 years.

We’ve been hanging out with bees for a long time, about as long as we’ve been hanging out with any other animal, with the notable exception of cats and dogs. It seems that in the course of human development, we first made friends and then made food. That’s nice. We’re not all bad.

Over recent decades, we have collectively become aware that there’s something weird going on with the bees. At least certain species of them. There has been widespread anxiety about the health and maintenance of critical pollinators, with some even claiming that bees are destined to go extinct, and soon. Phrases like “colony collapse disorder” became common household terms and we all held our breath waiting for the last of the bees to disappear. In actuality, the truth is a lot more complicated than that and bees are probably going to be just fine, at least in the wide view. But some bees, particularly captive bees, have been struggling and new research might have revealed part of the reason why.

According to a new study carried out by Anthony Nearman and Dennis vanEngelsdorp from the University of Maryland, published in the journal Scientific Reports, the lifespan of captive bees is shrinking. In fact, over the last half century, the average lifespan of an individual bee kept in a laboratory setting has been cut nearly in half.

Honeybee colonies are superorganisms, meaning a collection of specialized individuals who work together to survive and thrive. One could make the argument that humans are also a superorganism, but that’s a discussion for another time; honeybees certainly fit the bill. They don’t spend a lot of time alone and can’t really survive without their peers, or the intervention of humans, for long stretches. That said, scientists often work with individual bees because it allows a greater degree of control, something crucial to the function of reliable science.

To that end, scientists have an interest in keeping their bees alive and healthy as long as possible. Often, experiments involving individual bees don’t last that long under the best of circumstances, usually only a couple of months, depending on the species, its role in the hive, and the season. Honeybees live longer over the winter than in the summer and queens live longer than workers. Just your typical insect class warfare.

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Researchers discovered that one way to extend the lifespan of their bees was to provide them a variety of waters to choose from, in addition to nectar. Bees with the choice of deionized, 1%NaCl in deionized, or tap water — essentially waters with various levels of salt — lived longer on average than peers who were not given options. Based on that discovery, researchers began looking into the history of water provisioning in experiments involving bees, and they found something unexpected. The average lifespan of captive honeybees had declined significantly since the 1970s. All told their average lifespan had been cut almost in half, from 34.3 days to 17.7 days.

The question was whether shrinking lifespan is an artifact of the laboratory setting or something being seen in the wider world. It appears to be the latter. Researchers found that the decline in lifespan lines up nicely — or not so nicely, depending on your perspective — with that of honey production per colony per year in the United States over the same time period. Shorter lifespan means higher colony turnover, less time for the veteran honey producers to really get going. It isn’t difficult to see how shrinking lifespan would result in lower honey production. That hits honey farmers but it also hits the bees, who depend on the honey to survive.

Researchers also plugged the declining lifespan into their bee population models (cleverly named BEEHAVE) and the colony loss rates they calculated lined up with what contemporary beekeepers are experiencing. The world is definitionally not a laboratory, it isn’t controlled, and we can’t double blind it, so it’s difficult to say for certain if declining lifespan is the only or even primary cause of bee decline, but it seems reasonable that it wouldn’t help.

In terms of a mechanism, a driving cause of this change, the jury is still out but researchers suspect a genetic component. There appears to be some relationship between the size of a colony and how long individual bees live. Bees from larger colonies tend to live longer, but it’s unclear which drives the other. Do bigger hives make longer-lived bees or do longer-lived bees make bigger hives? There are also benefits to having shorter lives, as counterintuitive as that may seem. Bees who live longer are more likely to pick up pathogens or parasites and carry them back to the hive where they can easily proliferate. Hives with a shorter average lifespan tend to have lower incidents of disease.

It's possible that the relationship between lifespan and disease backfired as an unintended consequence of selective breeding on farms. Farmers look at their hives and choose the ones with fewer diseases to breed the next generation, unaware that the choice is driving their bees, one generation at a time, toward shorter lives. The problem is, compared to us, bees are so ephemeral. Their lives, even when appropriately long, are blips compared to ours. And there are so many of them. It’s no wonder we didn’t notice they were all living fast and dying young until the problem had stacked up enough for us to see.

Importantly, this isn’t a cause for panic. Bees are, on the whole, doing fine and more knowledge is nearly always a good thing. With additional study and targeted effort, bees of the future can return to living into what they consider old age instead of dying in the midst of a mid-life crisis at two-weeks old.