A monarch butterfly migration gene has been discovered in a new study published in this week's issue of the journal "Nature." According to the research, the butterfly migration gene can explain why some of the monarch's population had physiques equivalent to an athlete.
The migration of the monarch butterflies in North America, a 3,000-mile (4,800-km) mass migration, is reportedly one of the insect world's most incredible feats. Millions of these strapping arthropods take on a gruelling journey which reaches as far north as Canada down into Mexico and the California coast every autumn, reports Reuters.
On Wednesday, scientists revealed a new insight into the monarch butterfly migration gene, which is an essential factor into how the insects are able to go through their yearly expeditions.
As published in the journal "Nature", the study on the monarch's genetic analysis not only revealed how the butterfly migration gene is related to flight muscle efficiency, but it also includes how monarchs got their striking orange-and-black color pattern.
Also, it was detailed in the study that they initially dispersed out of North America, rather than Central or South America, as previously thought.
"I find it amazing that these little butterflies live for months and fly thousands of miles to perform this annual migration," said Marcus Kronforst, one of the study's researchers and a professor of ecology and evolution at the University of Chicago.
"Our study shows that monarchs have been doing this every year for millions of years. There is nothing else like this on the planet," the evolutionary biologist added.
Led by Shuai Zhan of the Shanghai Institutes for Biological Sciences, the international team of scientists were able to unravel the monarch butterfly migration gene by using 101 butterflies. These included 92 monarchs, as well as nine specimens from other butterfly species.
"The reason we did so many different analyses in our paper was because some of the coauthors of the paper took so much convincing," Kronforst said.
In order to study the monarch's genetic basis for migration, the researchers compared the genetic blueprint of migratory monarchs to those that don't
"One gene really stood out from everything else in the genome," said Kronforst.
The butterfly migration gene is known as the Collagen IV alpha-1. According to the paper, it is the main ingredient in connective tissue essential for flight muscle function.
Apparently, the researchers had been dumbfounded in finding out that the butterfly migration gene was less active in migratory butterflies. Instead of making the migratory insects big and powerful fliers, the gene enhanced their flight efficiency.
Kronforst said that though the discovery was surprising, it reportedly "made sense."
"They have to be big and tough and powerful," said Kronforst.
He added, "Then we did the experiments. And it turns out the migratory butterflies have less" of the butterfly migration gene. "I thought: This doesn't make any sense," Kronforst said. "They should be doing more, not less."
The study also found that the monarch's ancestor likely came from what is now the southwestern U.S. and northern Mexico, reports the Los Angeles Times.
Monarchs reportedly came into existence 2 million years ago. The migratory ones spread to Central and South America about 20,000 years ago. About 2,000 years ago, they began crossing the Pacific and Atlantic oceans, possibly even surpassing massive storms, according to the study.
Another stunning revelation in the study is how monarchs acquired their signature color, an "orange flag" of toxicity. Their wings, orange with black veins and white spots along the outside edges, have served them well by warding off predators.
According to scientists, the citrusy color tells potential predators that these insects taste awful and thus toxic to eat. Monarchs got the color of their wings from chemicals of milkweed plants that nourish them during the larval state.
Their wingspan is reportedly about 4 inches (10 cm) and their bodies are black.
According to Kronforst, monarch butterflies that inhabit east of the Rocky Mountains travel to Mexico in the winter to flee the cold weather. Meanwhile, those in the west of the Rockies spend winters on the California coast, but they return home in the spring.
What Is The Study's Significance?
It is not a well-known fact that the number of migrating monarchs has already plummeted in recent years. In 1996, an estimated one billion monarch butterflies migrated to Mexico, but in the past winter, only 35 million were left.
NBC News reports that the devastating decline in the Midwest is due to a wide range of factors including climate change, habitat loss from deforestation and human activities; and drought and pesticides that kill milkweed, which is the monarchs' main source of nourishment.
While finding out about the monarch butterfly migration gene does not necessarily suggest new strategies to save the species, learning about the vast wonders of monarchs' capabilities and genetic makeup could emphasize the importance of preserving the iconic species whose lifestyle goes back to millions of years, according to Kronforst.
"We are seeing possibly the tail end of this phenomenon of migration," Kronforst said. "To me, it adds a sad exclamation point to the story."
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