New research shows that honeybees are living half the lifespans they used to only 50 years ago.
Researchers from the University of Maryland published their findings in Scientific Reports on November 14. In the 1970s, bees in captivity would live an average of 34.3 days, whereas bees in Dennis van Engelsdorp’s lab lived only 17.7 days.
The research was conducted by entomology Ph.D. student Anthony Nearman, who discovered this phenomenon while conducting a study using the standard protocols for taking care of bees in the laboratory. Bee pupae are taken from their hives when they are 24 hours away from emerging as adults. Then, they are collected and grown in special incubators and cages during their adult lives.
While doing this procedure, Nearman noticed that regardless of the diet he fed his colony, the lifespan of his honeybees was only half of what was reported in early studies.
This led to a comprehensive look at multiple studies over the past fifty years, which corroborated their results.
“Standardized protocols for rearing honeybees in the lab weren’t really formalized until the 2000s,” Nearman explained. “So you think that lifespans would be longer or unchanged because we’re getting better at this, right? Instead, we saw a doubling of mortality rate.”
The dying bee population is on the mind of beekeepers and farmers. Over the past ten years, beekeepers have noticed that they are replacing their colonies more quickly. To understand why this has been happening, researchers have turned to look at disease, parasites, pesticides, or other environmental stressors, but this is the first study done independently of these factors.
While the lab environment is different than the real world, previous research has shown that the lifespan of bees in the lab is similar to the lifespan of colony bees. This led to a general assumption that factors that affect honeybee lifespan in one environment will translate to another.
When the researchers modeled the 50% lifespan reduction to a beekeeper’s colony, the losses were similar to the average losses reported by beekeepers over 14 years of around 30-40%.
Nearman’s best hypothesis is that there’s a genetic factor controlling the shortening lifespan of the honeybee, which is a phenomenon found in other insects like fruit flies.
If the cause of the shortening lifespan is genetic, breeding honeybees to compensate for this factor could lengthen their lifespans.
For future work, Nearman and van Engelsdorp plan to compare trends in honeybee lifespans across the US and other countries to determine if this phenomenon is region-specific.
Sources: EurekaAlert, Scientific Reports