A female loggerhead turtle nests in the sand in Florida. Photo credit: Gustavo Stahelin / UCF Marine Turtle Research Group. Approval Number: FL MTP-186
Despite 50 years of research, the question remains unsolved.
A researcher from the University of Central Florida is co-authoring a new paper that may help answer why some animals have a magnetic “sixth” sense, such as the ability of sea turtles to return to the beach where they were born.
Despite 50 years of research, the question remains unsolved.
“The search for a mechanism has been suggested as one of the last great frontiers in sensory biology and has been described as looking for a needle in a stack of needles,” said Robert Fitak, assistant professor in the UCF’s Department of Biology. Part of the UCF College of Sciences.
Fitak and researchers in the UK and Israel recently wrote an article in Philosophical Transactions of the Royal Society B. this suggests a hypothesis that the magnetic sense stems from a symbiotic relationship with magnetotactic bacteria.
Magnetotactic bacteria are a special type of bacteria whose movement is affected by magnetic fields, including those of the earth.
Animals that sense the Earth’s magnetic field include sea turtles, birds, fish, and lobsters. For example, sea turtles can use the navigation feature to return to the beach where they were born.
Learning how organisms interact with magnetic fields can improve humans’ understanding of how the Earth’s magnetic fields can be used for their own navigational purposes. It can also educate ecological research on the effects of human changes in the magnetic environment, such as the construction of power lines, on biodiversity. Research into the interaction of animals with magnetic fields can also help develop therapies that use magnetism to deliver drugs.
In the article, the researchers review the arguments for and against the hypothesis, present evidence that has been published in support of the hypothesis that has emerged in recent years, and offer new supporting evidence of their own.
Their new evidence comes from Fitak, who has examined one of the largest genetic databases of microbes known as Metagenomic Rapid Annotations using the Subsystems Technology database for the presence of magnetotactic bacteria found in animal samples.
Previous microbial diversity studies have often focused on large patterns of the presence or absence of bacterial phyla in animals rather than specific species, Fitak says.
“The presence of these magnetotactic bacteria was largely overlooked in the massive volume of these data sets or was lost in the mud,” he says.
Fitak first discovered that magnetotactic bacteria are associated with many animals, including a species of penguin, loggerhead sea turtles, bats, and Atlantic right whales. For example Candidatus Magnetobacterium bavaricum occurred regularly in penguins and loggerhead sea turtles while Magnetospirillum and Magnetococcus Brown bats and Atlantic right whales occurred regularly in the mammal species.
According to Fitak, the researchers still don’t know where the magnetotactic bacteria would live in the animal, but they could be linked to nerve tissue like the eye or the brain.
“I’m working with the co-authors and local UCF researchers to develop a genetic test for these bacteria, and we plan to then look at different animals and certain tissues like sea turtles, fish, lobsters and birds,” said Fitak.
Prior to joining UCF in 2019, Fitak worked as a postdoctoral fellow at Duke University for more than four years, conducting experiments to identify genes related to magnetic sense in fish and lobsters using modern genomic techniques.
He says the hypothesis that animals use magnetic bacteria in a symbiotic manner to gain magnetic sense warrants further exploration but needs more evidence before anything conclusive can be established.
Reference: “Symbiotic Magnetic Perception: Raising Evidence and Beyond” by Eviatar Natan, Robert Rodgers Fitak, Yuval Werber, and Yoni Vortman, August 10, 2020, Philosophical Transactions of the Royal Society B..
DOI: 10.1098 / rstb.2019.0595
Fitak received his PhD in genetics from the University of Arizona and his bachelor’s degree in molecular genetics from Ohio State University. He is a member of the UCF Genomics and Bioinformatics Cluster.
The study co-authors included Eviatar Natan of The Aleph Lab, Ltd. in Oxford, England; and Yuval Werber and Yoni Vortman from Tel-Hai Academic College in Tel Hai, Israel.
