Lifespan of honeybees halved over the last 50 years

By Mark Waghorn via SWNS

The lifespan of honeybees has halved over the last 50 years, according to new research.

It now stands at just over 2 weeks - compared to more than a month in the 1970s.

The drop in longevity sheds fresh light on colony losses and drops in production.

It is the first study to identify an overall decline in the vital pollinators within a controlled environment.

It hints that genetics may be influencing the broader trends seen in the beekeeping industry - which has become increasingly trendy.

A host of celebrities have taken it up including Scarlett Johansson, Leonardo DiCaprio, Morgan Freeman and David Beckham.

Membership of the British Beekeepers Association has risen from about 8,500 people in 2008 to more than 24,000.

They have seen several poor seasons in a row. In 2020, beekeepers in the United States lost almost half of their colonies.

Last year French beekeepers announced an all-time low of fewer than eight tons - just half the amount produced in 2020.

Lead author Anthony Nearman, a Ph.D. student at Maryland University, said: "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.

"This introduces the idea of a genetic component. If this hypothesis is right, it also points to a possible solution. If we can isolate some genetic factors, then maybe we can breed for longer-lived honey bees."

The entomologist noticed the phenomenon while conducting a study on standardized protocols for rearing adult bees in the laboratory.

Replicating earlier results, Mr. Nearman and Professor Dennis van Engelsdorp collected pupae from honey bee hives when they were within 24 hours of emerging from the wax cells they are reared in.

The collected bees finished growing in an incubator and were then kept as adults in special cages.

Mr. Nearman was evaluating the effect of supplementing the bees' sugar water diet with plain water to better mimic natural conditions.

He realized their average lifespan was half that of caged bees in similar experiments in the 1970s.

It had fallen to 17.7 days today compared to 34.3 days in the 1970s - regardless of diet.
This prompted a deeper review of published laboratory studies over the past 50 years.

Honeybees produce about one-third of our food by sustaining fruit, vegetables and cereals.

They are being wiped out by climate change, pesticides and diseases.

Mr. Nearman said: "When I plotted the lifespans over time, I realized, wow, there's actually this huge time effect going on.

"Standardised protocols for rearing honey bees in the lab weren't really formalized until the 2000s.

"So you would think that lifespans would be longer or unchanged because we are getting better at this, right? Instead, we saw a doubling of mortality rate."

Historical records of lab-kept bees suggest a similar lifespan to colony bees. Scientists generally assume that isolated factors that reduce the lifespan in one environment will also reduce it in another.

Previous studies had also shown in the real world, shorter honey bee lifespans corresponded to less foraging time and lower production.

The study in Scientific Reports is the first to connect those factors to colony turnover rates.

Mr. Nearman and Prof van Engelsdorp also modeled the effect of a 50 percent reduction in lifespan.

On a beekeeping operation, where colonies are replaced annually, the resulting loss rates were around a third.

This is very similar to the average over winter and annual loss rates of 30 and 40 percent reported by beekeepers over the past 14 years.

The researchers said their lab-kept bees could be experiencing some sort of low-level viral contamination or pesticide exposure during their larval stage when they are brooding in the hive and worker bees are feeding them.

But the bees have not shown overt symptoms of those exposures and a genetic component to longevity has been shown in other insects such as fruit flies.

The next steps will be to compare trends in honey bee lifespans across the US and in other countries.

If they find differences in longevity, they can isolate and compare potential contributing factors such as genetics, pesticide use and presence of viruses in local bee stocks.

Honeybees have such short lives because of their small size - coupled with a heavy workload.

Despite an individual's brief existence, a colony can survive for years due to the queen's extraordinary ability to lay 1,500 to 2,000 eggs per day. She can live for up to two years.

Wild bees and are in decline. If current trends continue, certain species will be lost altogether.