Most people are familiar with the decline of honeybee colonies around the world. Among other threats, Colony Collapse Disorder (CCD) is eroding the capability of honeybees to maintain their hives and provide their services to human farmers.
Not usually discussed as major drivers of the economy, honeybees and other pollinators are responsible for keeping fruits and vegetables on our table. While honeybees do a lot of the heavy lifting, bats, butterflies, birds, and other species of bees are also part of an ecosystem of pollinators that enable human agriculture.
Despite their small size, pollinators have an outsize impact on the economy of the US. As noted by the Obama White House, insect pollinators are "integral to the food security of the United States."
Heads-up facts about their value include:
- Pollinators push over 24 billion dollars into the US economy, and honeybees account for over $15 billion of that total.
- Around the world, 87 of the world's leading 115 food crops are dependent on pollinators. These crops account for about 35% of our global food resources.
- In North America, honeybees support the growth of 90 or more commercial crops.
At present, the rate of loss of overwintering honeybee colonies is fluctuating. In 2015, beekeepers in the US lost a staggering 44% of their colonies. Harsh weather, climate change, natural predators, habitat loss, disease, and pesticides are taking their toll, often in the form of CCD.
In 2006, beekeepers took notice of increasing numbers of their honeybee colonies going into sudden and stark decline. CCD is typified by:
- Despite the presence of a queen, and larvae, worker bee populations vanish, leaving the hive unattended, and the queen and brood to die.
- Few bees are found dead in or near the hive.
- While occasional bee "disappearances" were historically recorded, the sudden upswing in honeybee colonies caused global concern. The unusual symptom of CCD is the lack of bees, or dead bees, near or in a once-thriving colony.
Researchers around the world continue to explore the constellation of threats that contribute to the death of bee individuals, and sometimes the collapse of their colonies. Recently, a Canadian study shed discovered a possible treatment for bees to help them survive the effects of toxic neonicotinoid insecticides — and it sounds suspiciously like something that should be in your yogurt: Probiotics.
With the explosive increase in knowledge about the human microbiome, the importance of bacteria has gone mainstream. Prebiotics and probiotics, in the form of pills and foods, are money-makers used, with and without scientific support, in the hope of improving gut health. Research continues to link gut health with immune function, digestive efficiency, and protection against pathogens.
In the new study, published in Scientific Reports, researchers investigated whether a probiotic could provide an assist for honeybees knocked back by pesticides and environmental stress. Turns out the most common strain of bacteria found in yogurt, Lactobacilli, works for honeybees too.
For its study, the research team from Lawson Health Research Institute and Western University used a fruit fly, Drosophila melanogaster, to model an approach to reduce the impact of pesticide toxicity on honeybees. Why fruit flies? The function, composition, and structure of the immune system and gut microbes of fruit flies are similar to the bees, making them a good stand-in. Fruit flies and honeybees experience similar serious effects when exposed to neonicotinoid pesticides.
Neonicotinoid pesticides are chemicals that quickly impact the nervous system of organisms exposed to them. The insecticides cause paralysis, and then death. There are several, highly toxic, compounds in this class of insecticides, and they are not healthy for humans, either.
Using neonicotinoid insecticide, the scientists exposed the flies to a dose similar to what the flies would experience in a treated field. The young adult fruit flies were maintained with cornmeal, corn syrup, and other nutrients, and kept at average temperatures, with light and dark cycles.
Scientist already knew that the pesticides suppress the immune system of its targets. Plus they knew fruit flies and honeybees have abundant species of Lactobacillus species bacteria in their gut when healthy. The team subjected the fruit flies to stresses including:
- Pesticide exposure
- Bacterial infection
Because these stressors reduced the abundance and diversity of gut microbiota in the fruit flies, researchers tested whether using a probiotic supplement with Lactobacillus species bacteria could boost the immune signaling in the gut of the fruit flies and offer them a better chance of survival under clearly life-threatening circumstances. They turned out to be right.
When researchers exposed the fruit flies to the pesticides, it damaged their microbiota, and the flies became more vulnerable to infection, heat, and environmental stress. The scientists identified an immune pathway that regained some function when the fruit flies were given the probiotic bacteria — in pollen patties laced with Lactobacillus bacteria. Findings include:
- The alteration of the immune pathway with the probiotic was enough to improve the life expectancy of fruit flies in the study. Study authors note the fruit flies exposed to pesticides had "significantly increased absolute abundance of intestinal Acetobacter and Lactobacillus genera."
- Treatment with the probiotic L. plantarum "was shown to increase survival, lessen gut epithelial damage," and reduce the migration of helpful bacteria out of the gut, as a result of infection with harmful pathogens.
- Flies exposed to the probiotic has "significantly better overall survival and less early-time-point deaths" compared to flies exposed to pesticides that did not receive the probiotic treatment.
- Probiotics aside, flies exposed to neonicotinoid pesticides were less likely to survive bacterial infection or heat stress, demonstrating the ongoing danger of these insecticides in the environment.
- The study team notes the use of Lactobacilli before exposure to toxic pesticides helped the fruit flies survive intense environmental stress, and they believe the results could be similar for honeybees.
Researcher Brendan Daisley notes in a press release, "our study showed that probiotic lactobacilli can improve immunity and potentially help honey bees to live longer after exposure to pesticides." Gregor Reid, Director of the Canadian Centre for Human Microbiome and Probiotic Research, summed it up well when he said:
Until we can cease using pesticides, we need to find ways to protect humans and wildlife against their side effects. Probiotics may prove as an effective protective intervention against colony collapse disorder.
In the name of progress, we have poisoned ourselves and the environment in which we live and raise our families. History will record if we were able to save the honeybees, the natural world — and ourselves.