The spots on Monarch butterflies' wings could be much more important than we thought

Every year, after spending the summer in Canada, thousands of Monarch butterflies make a 2,000-mile trip to Mexico for the winter. They breed four generations along the way, and only about 30% make it.

Researchers have found a common trend among the specimens that survive one of nature's longest migrations: more white spots.

Dr. Andy Davis, a biologist at the University of Georgia, and one of the study's authors, explained to The New York Times that he was curious about how wing temperature affected Monarchs' flight.

In other species, like seabirds, he said, darker feathers (which absorb more heat) can help change airflow patterns and fly more efficiently.

But he found the opposite: the Monarchs that reach Mexico have bigger white spots on the edges of their wings.

Image: Davis, A. K., Herkenhoff, B., Vu, C., Barriga, P. A., & Hassanalian, M. / PLOS ONE, 2023

Dr. Davis believes the spots can reduce resistance by forming cool and hot air pockets. The next step will be to test that hypothesis using a wind tunnel and artificial Monarch wings.

The results could help scientists understand more about the Monarch's fascinating journey through North America ─something that needs our attention.

Migration patterns help conservationists to have an idea about how healthy the butterfly's population numbers are. It has significantly decreased since the 1980s when millions traveled.

Last year the International Union for Conservation of Nature (IUCN) listed the monarch butterfly as endangered, suggesting the species will go extinct without significant intervention.

Volunteers who visit sites in California and Arizona around Thanksgiving and New Year's every year help count the butterflies to track the population increases and decreases.

The sites are marked along the west coast following the migration patterns of the western monarch butterfly.

The last New Year's count revealed a 58% seasonal decrease in population due to the heavy rains. Typically, there are around 35% to 49% fewer butterflies than at Thanksgiving, according to the Xerces Society.

However, the 2022 Thanksgiving count had positive results. According to AP, 330.000 specimens were spotted along the west coast, the largest number in the past six years.

2022 marks the second year of population growth for the orange and black insects. Last winter, researchers registered an increase of more than 80.000 butterflies. In 2021, the number recorded was 247,000.

"A second year in a row of relatively good numbers gives us hope," Emma Pelton, a conservation biologist at the Xerces Society, said in a press release.

The 2021 and 2022 counts were a substantial relief for conservationists after only counting 2.000 butterflies in 2020.

According to AP, a 2017 study by Washington State University predicted that the monarch would likely go extinct if its population dropped below 30.000. That is what happened in 2018 and 2019.

Research shows that the main reason monarch butterflies are vanishing is the destruction of their environment: milkweed, as green areas disappear to give space for housing projects, and more pesticides and herbicides are used.

Climate change also affects the 3.000-mile migration pattern in which the monarchs breed multiple generations before reaching California, where they latch on to trees to survive the winter.

Climate change also results in extreme weather and wildfires that affect the monarch population.

If you live in California or anywhere where monarchs fly by, there are many ways you can help to protect these beautiful butterflies from extinction. Most actions are simple.

Milkweeds are the required host environment for the monarch butterfly's caterpillar. If you have a garden, you can locate and plant seasonal native milkweeds to help the butterflies reproduce.

Avoid pesticides and herbicides in your garden, or look for less harmful alternatives. Most of these products are toxic for the butterflies or the milkweed.

You can volunteer to visit one of the sites where the monarchs rest during the winter in California. Conservation organizations offer training and information about the steps to follow.