Subscribe to our weekly newsletter
Baby bees hatch with damaged brains thanks to pesticides
Study finds that a colony's exposure to pesticides impairs offspring.
- Pesticide contamination in bee hives damages the learning capabilities of offspring, according to a recently published study.
- A key area of the affected bees' brains never correctly develops after pesticide exposure.
- Early impairment appears to be irreversible and is likely a factor in falling bee populations.
According to the U.S Department of Agriculture, some 35% of our food crops depend on bee pollination. That means about one of out every three bites of food comes to us courtesy of insects including bees, butterflies, and beetles, or from birds and bats. With the world's pollinator populations in a snowballing state of decline, scientists are racing to discover what's causing this and how it can be stopped. In the case of bees, pesticides — especially neonicotinoids — are the leading suspect, and studies find these chemicals infiltrating a significant percentage of bee hives. (Pesticides also show up in our own food and drink.)
Research prior focused on the damaging effects these neurotoxins have on adult bees. Now a study of young bee brains, led by Richard Gill of Imperial College in London and published in Proceedings of the Royal Society B, shows that neonicotinoids do disastrous, irreversible damage to bees' neurological development.
The study involved introducing neonicotinoids to the nectar consumed by members of 22 Bombus terrestris audax (buff-tailed honeybee) colonies. The learning abilities of their offspring were then measured against a control group of young bees from colonies whose food supply had not been contaminated.
The test assessed the extent to which a bee could learn to associate a specific smell with a reward, which was a sucrose solution. The bees from the neonicotinoid colony consistently fared more poorly than the control population.
Image source: Mr. Meijer/Shutterstock
Tiny computed micrography (CT) scans
In hopes of identifying a structural explanation, the researchers stained the brain cells of 100 bees from the exposed colonies and took non-invasive micro-CT scans in a machine similar — albeit smaller — to those in which humans are medically imaged.
The researchers discovered a clear difference in brains of the young bees from pesticide-exposed colonies. A key brain area, the mushroom body, was found to be much smaller in these bees' brains than it was in those from control colonies. This makes sense, since this region is believed to be involved in olfactory learning and memory.
The tests and scans were performed three days after pupal hatching and again after 12 days. The substandard learning capabilities and mushroom body sizes had not been resolved by the second test, indicating to the researchers that the damage caused by the neonicotinoids was irreversible.
(A honeybee's life expectancy depends on its role. Drones live roughly 8 weeks, while sterile workers live for about 6 weeks in the summer or 5 months in the winter. A queen can live for a few years.)
Several views of the mushroom body
Image source: Gill, et al
Why this matters
The study's conclusion does not say definitively that the mushroom area is the only brain region impacted by pesticides. However, a smaller mushroom area is significant, explaining, as it does, the mechanism by which a bee's learning abilities and behavior may be impaired over the course of its life.
Gill says in a press release, "Worryingly in this case, when young bees are fed on pesticide-contaminated food, this caused parts of the brain to grow less, leading to older adult bees possessing smaller and functionally impaired brains; an effect that appeared to be permanent and irreversible."
In fact, after the young bees were returned to their colonies, researchers saw lower-than-expected colony growth two to three weeks after the subjects' reintroduction.
"If future generations of workers are predisposed to be inefficient functioning cohorts, this could lead to a density-dependent build-up of colony-level impairment increasing the risk of colony collapse." — Gill, et al
Illustration of *Bombus terrestris audax*
Image source: Duda Vasilii/Shutterstock
And then there’s the adult bees
In addition to the problems caused by the behavior of bees hatched with pesticide damage, it's not as if pesticide exposure necessarily abates later on. As lead author of the study Dylan Smith explains, "There has been growing evidence that pesticides can build up inside bee colonies. Our study reveals the risks to individuals being reared in such an environment, and that a colony's future workforce can be affected weeks after they are first exposed."
The study concludes that simply looking at the damaging effect of pesticide on adult bee population misses a significant, and more far-reaching, part of the story:
"Bees' direct exposure to pesticides through residues on flowers should not be the only consideration when determining potential harm to the colony. The amount of pesticide residue present inside colonies following exposure appears to be an important measure for assessing the impact on a colony's health in the future. " — Gill, et al
- Bees and the environment - Big Think ›
- Bee colonies make decisions the same way the human brain does ›
- This Is Why You Never Swat that Fly - Big Think ›
- Rutgers-led research finds bee decline threaten crop yields - Big Think ›
A cave in France contains man’s earliest-known structures that had to be built by Neanderthals who were believed to be incapable of such things.
In a French cave deep underground, scientists have discovered what appear to be 176,000-year-old man-made structures. That's 150,000 years earlier than any that have been discovered anywhere before. And they could only have been built by Neanderthals, people who were never before considered capable of such a thing.
Water may be far more abundant on the lunar surface than previously thought.
- Scientists have long thought that water exists on the lunar surface, but it wasn't until 2018 that ice was first discovered on the moon.
- A study published Monday used NASA's Stratospheric Observatory for Infrared Astronomy to confirm the presence of molecular water..
- A second study suggests that shadowy regions on the lunar surface may also contain more ice than previously thought.
Credits: NASA/Daniel Rutter<p>Still, it's not as if the moon is dripping wet. The observations suggest that a cubic meter of the lunar surface (in the Clavius crater site, at least) contains water in concentrations of 100 to 412 parts per million. That's roughly equivalent to a 12-ounce bottle of water. In comparison, the same plot of land in the Sahara desert contains about 100 times more water.</p><p>But a second study suggests other parts of the lunar surface also contain water — and potentially lots of it. Also publishing their findings in <a href="https://www.nature.com/articles/s41550-020-1198-9#_blank" target="_blank">Nature Astronomy</a> on Monday, the researchers used the Lunar Reconnaissance Orbiter to study "cold traps" near the moon's polar regions. These areas of the lunar surface are permanently covered in shadows. In fact, about 0.15 percent of the lunar surface is permanently shadowed, and it's here that water could remain frozen for millions of years.</p><p>Some of these permanently shadowed regions are huge, extending more than a kilometer wide. But others span just 1 cm. These smaller "micro cold traps" are much more abundant than previously thought, and they're spread out across more regions of the lunar surface, according to the new research.</p>
Credit: dottedyeti via AdobeStock<p>Still, the second study didn't confirm that ice is embedded in micro cold traps. But if there is, it would mean that water would be much more accessible to astronauts, considering they wouldn't have to travel into deep, shadowy craters to extract water.</p><p>Greater accessibility to water would not only make it easier for astronauts to get drinking water, but could also enable them to generate rocket fuel and power.</p><p style="margin-left: 20px;">"Water is a valuable resource, for both scientific purposes and for use by our explorers," said Jacob Bleacher, chief exploration scientist in the advanced exploration systems division for NASA's Human Exploration and Operations Mission Directorate, in a statement. "If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries."</p>