The life expectancy of the honey bee may be half of what it was 50 years ago

The researchers estimate that this figure is the cause or at least strongly related to the beehive collapse syndrome

By Dave Golson, Professor of Biology (Evolution, Behavior and Environment), University of Sussex

A new paper shows that the lifespan of the adult honey bee has decreased by almost 50% in the last 50 years. The European Red List for Bees indicates that almost one in ten species of wild bees is facing extinction. Imagine how we would react if the human lifespan were halved. The equivalent would be if The average woman in Britain She lived to the age of 41 instead of 82 (in Israel 42 instead of almost 84.5 AB)

Our future is integrated into that of the bees. Without bees and other pollinators, we would not be able to grow most of the crops we depend on for food.

This research can help explain the The high rate of collapses hives around the world in recent decades. Bee deaths were particularly severe in the US in the winter of 2006-7, when some commercial beekeepers lost 90% of their colonies.

High and inexplicable rates of deaths from bee colonies Also reported in Canada, Australia, Belgium, France, Netherlands, Greece, Italy, Portugal, Spain, Switzerland, Germany, Finland and Poland. In the cold winter of 2012-13, 29% From the honey bee colonies in Britain died

50 years of data

The authors, Anthony Nierman and Denise Van Engelsdorp of the University of Maryland, used in mathematical models To show that a lower life expectancy of bees can lead to mass death in the colony. According to their research, since 1969, the lifespan of the honey bee in the US has dropped from a median of 34 days to just 18 days.

The researchers studied worker bees that were removed from hives and kept in cages, rather than wild bees, which may have influenced their results. But if not, something really worrying is going on.

The authors believe that modern honey bees may suffer from a higher incidence of diseases such as The twisted wing virus, which has become more common since its discovery 40 years ago, due to the global spread of its carrier, a mite The varroa. Modern bees may be weakened by New generations of pesticides that did not exist 50 years ago.

Often the pollen that the bees feed to their larvae is contaminated with pesticides. This can make matters worse because bees exposed to low doses of a highly toxic group of pesticides called neonicotinoids They showed less resistance to diseases.

Another explanation offered by the authors is that the genes of the bees may have changed. Artificial (by beekeepers) or natural selection may favor bees with a shorter lifespan. Scientists see this happening in other species. for example, cod fish reach maturity today earlier and at a smaller size because overfishing means that fish hardly survive long enough to grow.

Perhaps stressors in the modern world, such as pesticides and disease, mean that honeybees rarely survive for long. So their evolution may favor it Fast lifestyle and death at a young age.

Everyone's problem

The bees are already facing many pressures for their survival. A separate study of the University of Bristol, published in November 2022, found that fertilizers change the electric field of plants, which changes the way bees sense flowers. This repels them from visiting these flowers and the habitat of the bees is disappearing. Since the 30s, 20% of wildflower fields have been lost in Britain as agriculture intensified.

Fascinating as it is, the new research raises more questions than it answers (as good science usually does). The data is based on groups of worker bees kept in cages. This method is often used to Investigate the effects of stress factors (such as pesticides) on bees.

In these types of experiments, researchers would usually set up control groups at the same time and under identical conditions. Nierman van Engelsdorp used the historical data from control groups in many such studies conducted across the US since 1969. As the authors admit, this is a weakness in their report.

They cannot guarantee that lab conditions have remained the same since 1969. Perhaps older studies tended to use wooden hives and more modern studies used plastic. Cage sizes may be smaller or larger. The air flow in modern incubators may now be faster - or slower. Such details are rarely specified. Anything that has changed in the last 50 years can explain the decline in life expectancy.

It will not be easy for scientists to decipher the research findings. But if we could find historical data on the lifespan of the wild honey bee from previous decades, we could compare it to measurements from today's world. This will help scientists rule out the possibility that the results of the study were influenced by the laboratory conditions.

A decrease in the lifespan of the bees means a reduction in pollination. Bees and other pollinating insects are essential to a good harvest for 75% of the crops we grow around the world. They are also pollinators About 80% of all wild plants. All bee species face similar challenges to honey bees, but we don't know if their life spans have changed. If the bees really live less time in the wild, we need to know why.

For an article in The Conversation

More of the topic in Hayadan:

• The health significance of extending life expectancy
• Everything is honey (but only for now)
• "With the help of the insight we received from decoding the genome of the bees, we will be able to fight the collapse of the beehives"
• The bee's brain pays a price to allow accelerated development of the ovaries
• New research: honey bees create social distance in order to prevent disease transmission