Does the world’s tiniest GPS go in a brain of an insect?

How can insects with their tiny brains navigate over large distances? Do they have a built-in GPS in the form of a magnetic sense? Eric Warrant, Professor of Sensory Biology at Lund University, studies the ability of small insects to navigate with the help of the Earth’s magnetic field.

Eric Warrant is studying if there is a sort of sixth sense in insects, known as a magnetic sense. A magnetic compass has previously been confirmed in seasonally migratory vertebrates with relatively large brains, such as migratory birds, turtles, and fish.

“But in seasonally migratory insects with their tiny brains, the use of a magnetic compass has not previously been identified with certainty”, says Eric Warrant.

Preliminary data from research on night-flying moths in Australia show that the bogong moth uses a magnetic sense to utilise the Earth’s magnetic field as a compass. The bogong moth flies approximately 1 000 km back and forth each year in southeast Australia. Billions of bogong moths hatch each spring. Without any experience in migratory routes and destinations, they fly to the Snowy Mountains area where they seek out cool caves located nearly 2 000 metres above sea level. Here the moths rest for three to four months.

In early autumn, they leave the caves and fly back to the place where they were hatched. Here they mate, lay eggs and then die. How do the bogong moths find their way to the caves? And, several months later, back to their birthplace? Where in the moths’ nervous system is the magnetic sensory organ located, how it is structured and how does it work? Eric Warrant hopes to answer these questions in his new project.

“The bogong moth is an excellent model system for studying how information from the Earth’s magnetic field is detected and interpreted by the nervous system – a fundamental question which is so far completely unanswered, and something of a holy grail in sensory biology”, says Eric Warrant.

The project entails basic research, but many industry and military stakeholders are interested in how seasonally migratory animals navigate across vast distances, and the sensory information they use to find a specific yet unknown destination far from home.

“In a politically unstable world where GPS and other artificial navigation systems are very vulnerable, it has become particularly interesting to find answers to how animals have solved similar problems”, says Eric Warrant.

Text: Lena Björk Blixt

In the spring of 2017, Eric Warrant, a professor at the Department of Biology, received a prestigious grant from the European Research Council of almost SEK 25 million for his project on small insects’ ability to navigate with the help of the Earth’s magnetic field.

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