Animals like geese, pigeons, turtles and wolves are already known to make use of Earth’s magnetic field for their directional ventures. But this is the first time that humans have been able to actually identify an organ that is specifically suited to such magnetic field-oriented navigational tasks. To that end, a group of researchers and engineers at the The University of Texas (in Austin) has classified what is essentially the world’s first discovered organic sensor – found in the brain section of a tiny worm known as C. elegans. This sensor was found to be in a microscopic scale at the end of a neuron, with its shape roughly resembling a tiny television antenna.
Interestingly, while researching about conditions like addiction and Alzheimer’s disease, the experts had already noted the ability of the C. elegans to sense humidity. On further examination, they also discovered that some hungry worms tend to move downwards when kept in gelatin-filled tubes. However, worms collected from other geographical areas of our planet were found to opt for the variant actions – by moving in different directions in search of their food. These directional actions were later gauged to be at precise angles to the Earth’s magnetic field. For example, the Australian worm was actually found to move upwards, a direction that hints at the Earth’s magnetic field orientation from Australia.
As for the more specific side of affairs, the scientists (for this project) decided to test out the worm’s so-called magnetosensory abilities. As a result, they intentionally altered the magnetic field around the worm specimen with the help of a magnetic coil mechanism. The changes in neuron activity of the worm suggested that the organism had the natural habit to use its built-in sensor for navigation. Furthermore, the neuron embedded with this specialized sensor (known as the AFD neuron) was also found to detect other environmental parameters like temperature and carbon-dioxide levels.
The study was published in the journal eLife.