According to a recent study, individual honey bees reared in a controlled laboratory environment today have 50% shorter lives than they did in the 1970s.
According to a recent study by entomologists at the University of Maryland, the longevity of individual honey bees kept in a controlled laboratory environment is now 50% shorter than it was in the 1970s. Scientists’ simulations of the impact of today’s shorter lifespans matched the trends in decreased honey production and higher colony loss observed by American beekeepers in recent decades.
The natural ageing and death of bee colonies makes colony turnover a recognised aspect of the beekeeping industry. However, during the past ten years, American beekeepers have reported high loss rates, which have necessitated the replacement of more colonies in order to maintain operations. Researchers have concentrated on pesticide exposure, environmental stresses, parasites, illnesses, and nutrition in an effort to comprehend why.
The fact that this study is the first to document a general loss in honey bee longevity that may be unrelated to environmental stressors suggests that genetics may be playing a role in the general trends observed in the beekeeping sector. Today, November 14, 2022, the study will be released in the journal Scientific Reports.
Research from the University of Maryland indicates that caged bees live shorter lives than they did 50 years ago, despite higher standards for lab beekeeping. This suggests that something other than environmental factors may be to blame for commercial beekeepers’ higher rates of honey bee colony loss. Credit: UMD / Anthony Nearman
Anthony Nearman, a Ph.D. student in the Department of Entomology and the study’s primary author, explained that because bees are isolated from colony life just before they become adults, whatever is shortening their lifetime is occurring before that. The concept of a genetic component is introduced in this. If this theory is accurate, it also suggests a potential answer. Maybe we can breed for honey bees with longer lifespans if we can isolate some genetic elements.
While working with associate professor of entomology Dennis van Engelsdorp on a study on standardised procedures for growing adult bees in the lab, Nearman first became aware of the drop in lifespan. The researchers gathered honey bee pupae from hives within 24 hours of them emerging from the wax cells they are raised in, replicating past investigations. The gathered bees were raised to adulthood in an incubator and housed in special cages.
When Nearman found that, regardless of diet, the median lifetime of his caged bees was half that of caged bees in comparable trials in the 1970s, he began investigating the effects of supplementing the caged bees’ sugar water diet with plain water to better replicate natural conditions. 17.7 days as opposed to 34.3 days during the 1970s. This led to a more thorough evaluation of laboratory research that were published throughout the previous 50 years.
“I discovered there’s actually this big time impact going on when I plotted the lifespans across time,” Nearman added. You would assume that lifespans would be longer or unchanged because we’re becoming better at this because standardised techniques for growing honey bees in the lab weren’t actually developed until the 2000s, right? Instead, we saw a death rate that had doubled.
Despite the fact that a colony and a laboratory are very different environments, historical records of lab-kept bees suggest that they have a similar lifespan to colony bees. Additionally, scientists typically assume that isolated factors that shorten lifespan in one environment will also shorten it in another. Shorter honey bee lifespans in the actual world were also linked to less time spent foraging and reduced honey production, according to earlier studies. This research is the first to link such variables to colony turnover rates.
The resulting loss rates were around 33% when the team assessed the impact of a 50% reduction in longevity on a beekeeping enterprise, where lost colonies are rebuilt annually. This is quite similar to the 30% and 40% average yearly and overwinter loss rates recorded by beekeepers over the previous 14 years.
Nearman and vanEngelsdorp highlighted that the larval period, when the bees are brooding in the hive and being fed by worker bees, may be when the lab-kept bees are exposed to some form of low-level viral contamination or pesticide exposure. However, the bees have not manifested overt signs of such exposures, while fruit flies and other insects have demonstrated evidence of a genetic component to lifespan.
The researchers’ next steps will be to compare patterns in honey bee lifespans across the United States and in other nations. They can analyse and isolate potential contributing factors including genetics, pesticide use, and the presence of viruses in the local bee stocks if they discover disparities in longevity.