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Honey bees’ life expectancy is plummeting

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The world may soon be infested with serial killers. As we all know, honey bees play a crucial role in catching the likes of Jeffrey Dahmer, Ed Gein and more. If we don’t act now, the serial killers will prevail.

All joking aside, honey bee lifespans are 50% shorter than they were fifty years ago. This decrease in longevity in lab-kept honey bees may be to blame for recent declines in honey production and colony losses.

Honey bees’ lifespan decreased by 50%

A new study by entomologists at the University of Maryland reveals that the lifespan for individual honey bees kept in a controlled, laboratory environment is 50% shorter than it was in the 1970s. This decrease in lifespan for lab-kept honey bees could help explain colony losses and lower honey production in recent decades.The trends of increased colony loss and decreased honey production that have been observed by beekeepers in the United States in recent decades were mirrored when scientists modeled the effect of today’s shorter lifespans.

Honey bees’ colony health is declining

Since bee colonies naturally deteriorate and die, turnover in the colony is a common occurrence in the beekeeping industry. However, U.S. beekeepers have reported high loss rates over the past decade, necessitating the replacement of additional colonies to maintain operations’ viability. Researchers have focused on environmental stressors, diseases, parasites, pesticide exposure, and nutrition in an effort to comprehend why.

Changing genetics are the culprit

This is the first study to demonstrate a decline in the lifespan of honey bees as a whole that may not be caused by environmental stressors. This suggests that genetics may be influencing the general trends in the beekeeping industry. The study was published in Scientific Reports on November 14, 2022.
Lead author Anthony Nearman, a Ph.D. student in the Department of Entomology, stated, “We’re isolating bees from the colony life just before they emerge as adults, so whatever is reducing their lifespan is happening before that point.”The concept of a genetic component is introduced here. Additionally, it suggests a potential solution if this hypothesis is correct. We might be able to breed for honey bees with longer lifespans if we are able to isolate some genetic factors.”

The experiment

Nearman previously saw the decrease in life expectancy while leading a review with entomology academic administrator Dennis van Engelsdorp on normalized conventions for raising grown-up honey bees in the research facility. The researchers collected honey bee larvae from hives when the larvae were less than 24 hours from emerging from the wax cells in which they are raised, replicating earlier research. The collected bees were kept as adults in special cages after they finished growing in an incubator.
When Nearman noticed that, regardless of diet, the median lifespan of his caged bees was half that of caged bees in similar 1970s experiments, he was evaluating the effect of supplementing the sugar water diet of the bees with plain water to better mimic natural conditions. Lifespans were 17.7 days now, compared to 34.3 in the 1970s.This prompted a more in-depth examination of laboratory studies published in the past 50 years.
Nearman stated, “I realized, wow, there is actually this huge time effect going on when I plotted the lifespans over time. Since laboratory rearing of honey bees didn’t really get standardized until the 2000s, you’d think that lifespans would stay the same or grow longer because we’re getting better at it, right? Instead, the mortality rate doubled.”

Implications

Scientists generally assume that isolated factors that reduce lifespan in one environment will also reduce it in another, despite the fact that the environment of a laboratory is very different from that of a colony. However, historical records of bees kept in the laboratory suggest that they live to the same age as colony bees. In addition, previous research had demonstrated that, in the real world, shorter lifespans of honey bees were associated with less time spent foraging and lower honey production. This is the first study to link colony turnover rates to those factors.
The team calculated loss rates of approximately 33% when they modeled the effect of a 50% decrease in lifespan on a beekeeping operation that replaces lost colonies annually.This is very similar to the annual and overwinter loss rates of 30% and 40% that beekeepers have reported for the past 14 years, respectively.
According to Nearman and van Engelsdorp, their lab-kept bees may have been exposed to pesticides or a low-level virus during their larval stage, when they are brooding in the hive and worker bees are feeding them. However, the bees have not displayed any obvious signs of these exposures, and other insects, such as fruit flies, have demonstrated that there is a genetic component to longevity.

Future research

The next thing the researchers will do is compare trends in the lifespans of honey bees in the United States and other countries. They can isolate and compare potential contributing factors, such as genetics, pesticide use, and the presence of viruses in the local bee stocks, if they discover differences in longevity.

University of Maryland. (2022, November 14). Honey bee life spans are 50 percent shorter today than they were 50 years ago: A drop in longevity for lab-kept honey bees could help explain colony losses and lower honey production in recent decades. ScienceDaily. Retrieved November 29, 2022 from www.sciencedaily.com/releases/2022/11/221114095322.html

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