(SYDNEY) — Each year, a tiny species of moth in Australia embarks on a remarkable 620-mile (1,000-kilometer) nighttime migration, utilizing a navigation method previously known only to humans and migratory birds, according to a new study.
Breaking: Moths Use Stars for Navigation
The Bogong moths, seeking to escape the heat, travel each spring from southeastern Australia to the cool caves of the Australian Alps. Here, they enter a dormant state before flying back in the fall to mate and eventually die. Researchers have replicated this extraordinary journey in a lab and discovered that the starry night sky is a crucial navigational tool for these insects.
“It is an act of true navigation,” said Eric Warrant, head of the Division of Sensory Biology at Lund University in Sweden, and a coauthor of the study published in the journal Nature.
Key Details Emerge
In addition to using stars, the Bogong moths can detect Earth’s magnetic field, providing a backup navigation system if one fails. This dual system allows them to navigate with a small brain and nervous system, showcasing their remarkable abilities.
Testing Star-Based Navigation in Moths
Native to Australia, the Bogong moth, known as Agrotis infusa, is nocturnal with an adult wingspan of approximately 2 inches (5 centimeters). Despite their unassuming appearance, these moths have been found to possess extraordinary navigational skills.
“They’re a very nondescript little brown moth,” Warrant explained, highlighting their endangered status on the International Union for Conservation of Nature’s Red List.
Warrant and his team conducted experiments by capturing moths using a light trap. They attached a thin tungsten rod to each moth’s back, allowing them to fly freely while an optical sensor tracked their direction relative to north.
By the Numbers
- 620 miles: Distance of the moths’ migration
- 400 moths: Captured and released during experiments
- 50 moths: Examined to understand neural mechanisms
An Astounding Journey
About 400 moths were used in behavioral experiments, with a smaller group of 50 examined to understand their neural navigation mechanisms. Despite their small pupils, the moths can see the night sky 15 times more brightly than humans, allowing them to use the Milky Way as a visual compass.
“A little moth can’t see many stars,” Warrant noted, emphasizing their ability to navigate using enhanced brightness.
What Comes Next?
Apart from birds and humans, only a few animals, like the North American monarch butterfly and some dung beetles, navigate using celestial cues, but none match the Bogong moths’ precision over such long distances. The moths’ journey is innate, as they make the trip only once in their lifetime.
“Their parents have been dead for three months, so nobody’s shown them where to go,” Warrant stated, underscoring the moths’ instinctual navigation.
Expert Analysis
Jason Chapman, an associate professor at the Centre for Ecology and Conservation at the UK’s University of Exeter, highlighted the discovery of a new compass mechanism in migrating insects and the need for further research.
“Many questions remain,” Chapman said, pointing to the need to understand how the moths detect and use information from their star compass.
The findings contribute to the broader understanding of insect migration, as noted by Jane Hill, a professor of ecology at the University of York in the UK.
“This feat of insect migration is even more amazing given that different generations make the journey each year,” Hill remarked.
The study opens new avenues for research into the navigational abilities of other migratory insects, with potential implications for conservation efforts.
