Honeybees Use Magnetic Abdomens to Navigate
This study reveals more fascinating secrets about bees. These amazing creatures have so many abilities that are slowly being exposed by scientists so we understand bees better. The more we know, the more awesome we know bees are.
According to a team of biologists and physicists in Canada, honey bees have a magnetic structure in their abdomens that helps them to sense magnetic fields.
A series of behavioral and physics experiments were carried out on the insects by researchers, and these demonstrated that this sensory ability can be disrupted if you use a strong permanent magnet.
Bees are not unique in having a magnetic field to navigate, but what is not yet well understood is how the underlying mechanisms of “magnetoreception” make such navigation possible. Perhaps it is because some organisms, like bees and other creatures, contain magnetite, a ferromagnetic oxide of iron that is also found in some rocks. Other creatures with this ability are some birds, fish, reptiles, rodents and more.
Here is a 3:52-minute video about how bees navigate by Project Based Learning and while it is very well done and shares other "bee secrets" of navigation, it does not mention that bees have magnetic abdomens:
In 1997 Joe Kirschvink and his colleagues at the California Institute of Technology showed that honeybees respond to local magnetic fields in a way known to be consistent with magnetite-based magnetoreception.
In order to prove a disruptive effect, more recently researchers and their colleagues at Simon Fraser University in Vancouver have now shown that a ferromagnetic material consistent with magnetite exists in a honey bee’s abdomen.
Veronika Lambinet, Michael Hayden, Gerhard Gries and their colleagues discovered that the material can be magnetized using a strong permanent magnet. They also found that magnetizing live honey bees’ abdomens in this way disrupts its ability to navigate using local magnetic fields.
First the researchers dissected some honey bees by separating the bodies into three sections—heads, thoraxes and abdomens. Then they crushed the body parts into pellets to represent the three sections of a bee’s anatomy. They used SQUID, a superconducting quantum interference device, to measure the magnetization of each pellet as it was exposed to an applied magnetic field of varying strength and direction. The conclusive plots of magnetization versus applied field showed no evidence for ferromagnetism in pellets made from the heads and thoraces. However, a clear hysteresis loop indicated there was ferromagnetism in the abdomen sample.
A strong permanent magnet was then used by the team to expose live honey bees to a magnetic field of 2.2 kOe – several thousand times stronger than the Earth’s magnetic field – for about 5 seconds. SQUID was again used, this time to perform further measurements that revealed that pellets made from the abdomen of these bees were even more strongly magnetized than pellets made from bees that had not been exposed to a magnetic field.
A further experiment was carried out to see how this magnetization might affect the ability of live bees to navigate to a food source. First, a group of bees was trained by the team to locate a sugar reward in an environment where electrical coils created a magnetic field. Next, half the trained bees were magnetized and then compared to the un-magnetized control group when it came to their performance. The magnetized bees were unable to find the reward, which indicated that their magnetoreceptors were disrupted by the magnetization process.
The study did not provide information about the direct biological mechanisms involved in magnetoreception, but the fact that the magnetic sense could be disrupted leaves room for more studies, according to Hayden. He is also interested in future studies about the potential impact of industrial electromagnetic noise on the magnetoreceptor of bees and how it affects their overall well-being.
Hayden believes bees could become the best organism for studying magnetoreception and says future experiments could investigate the microstructure of the magnetoreceptor.
The findings of these studies were published at Royal Society Proceedings B in 2016 and can be read here.
Here is a 3:35-minute video by Science Magazine about magnetoreception in general for a better understanding of it:
Haven't you always wondered how bees find their way to flowers miles away and then return to their hives without difficulty? Maybe magnetoreception helps to explain it along with the other factors mentioned in the first video above.
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