According to experts, monarch butterflies have a compass that helps them migrate every year. A new study shows that monarch butterflies use their eyes, antennae, and a body compass to fly from North America to central Mexico every fall.
An internal compass, that is how monarch butterflies can make their annual 2,000-mile journey. This week, a new study published in the journal Cell Reports finally explained how millions of monarch butterflies can migrate and gave clues as to how the species locate food.
The insects are famous for their bright orange and black wings; they are also known for their extraordinary annual southward fall migration from the United States and southern Canada to Mexico. During the autumn migration, monarchs cover more than 2000 miles, traveling through the Rocky Mountains, California to enjoy hotter winters in Mexico.
The lead expert behind the study, Dr. Eli Shlizermanof, a mathematician at the University of Washington, revealed that they focused on the butterflies’ brains and “monitored the rates at which cells in their antennae and eyes fired, in order to model how the insects stay on track.”
Shlizermanof concluded that the butterflies’ eyes make it possible to track the sun’s position in the sky to know what time it is. The insects also have an internal compass or internal body clock, that is based on “the rhythmic expression of key genes that maintain a daily pattern of physiological processes and behavior,” which guide them.
Shlizermanof said:
“Their compass integrates two pieces of information – the time of day and the sun’s position on the horizon – to find the southerly direction. We wanted to understand how the monarch is processing these different types of information to yield this constant behavior, flying south-west each autumn.”
The paper revealed that unlike other species that have their updated internal clock controlled by the brain, the monarch’s compass is regulated by antennae. He added:
“We created a model that incorporated this information – how the antennae and eyes send this information to the brain. Our goal was to model what type of control mechanism would be at work within the brain, and then asked whether our model could guarantee sustained navigation in the south-west direction.”
The experts discovered that the eastern North American monarch is very smart because they have what is called a separation point “which controls whether the monarch turns right or left to head in the south-west direction – which changes location in their visual field throughout the day.” Dr. Shlizerman shared:
“The location of this point in the monarch butterfly’s visual field changes throughout the day. And our model predicts that the monarch will not cross this point when it makes a course correction to head back south-west. In experiments with monarchs at different times of the day, you do see occasions where their turns in course corrections are unusually long, slow or meandering.”
According to the study, the butterflies passed this innate knowledge on to each generation – which might not be around for too long. Another study revealed that the monarch butterfly population has significantly declined over the last decade. The study predicted an 11%-57% probability that this population will go extinct over the next 20 years.
