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Misinformation could cause Floridians to harm, not help, monarch butterflies, a scientist says

A display of monarch butterflies is laid out. Some are wilted, some are normal.
Jordan Adams
These monarch butterflies were found at Ormond Beach, Florida. The ones infected by the ophryocystis elektroscirrha parasite can be spotted by their smaller size, crippled wings, and dull colors.

An open letter from a researcher reveals that Floridians could be inadvertently contributing to the spread of a life-threatening parasite among monarch butterflies.

A research scientist from the University of Georgia wrote an open letter to Floridians, warning them about a life-threatening parasite spreading among monarch butterflies.

But the urgent letter says residents themselves may be inadvertently contributing to the spread of this debilitating condition.

According to Project Monarch Health, the parasite, known as ophryocystis elektroscirrha, can cause deformations, small size, impaired mating, and decreased flight endurance in monarchs.

Andy Davis is the scientist and author of the letter.

He’s studied monarchs for over 25 years and said that because of misinformation and emotions, Floridians are speeding up the spread.

“Unfortunately, Florida is in a situation where that problem is extreme right now, where people have gone out of their way to do things to sort of try to help the monarchs, which is really not helping at all,” Davis said. “It's sort of interfering with our ability to even conserve this butterfly, because people are going forward with actions based on their feelings, not based on what the actual research shows.”

Davis said that misinformation led people to confuse Mexico’s dip in monarch numbers with Florida.

According to a study of breeding in North American monarch butterflies, population figures in Florida had consistently been increasing.

Davis was a part of that study and said that because there were plenty of resources for butterflies, there was never any need for Floridians to step in and plant milkweed.

Monarchs seasonally migrate between Florida and Mexico, but the planting of non-native milkweed lured them to stay in Florida.

While the parasite is naturally occurring, when monarch’s choose not to migrate, it leads to problems.

“The way this parasite works is that the infected monarchs drop infectious spores of the parasite onto their milkweed,” Davis said. “The spores then get transmitted to the caterpillars, which then start the cycle again. And so with monarchs being present year-round in Florida, and the milkweed being present year-round, the spores are just building up everywhere.”

Diagram shows the life cycle of a parasite in monarch butterflies. The image traces each stage step by step.
Monarch Health
University of Georgia
Monarch butterflies infected with the parasite, known as Ophryocystis elektroscirrha, have spores found on the outside of infected monarchs. These tiny spores cover a butterfly’s entire body.

Davis added that almost every single monarch butterfly in Florida is likely infected, but that it’s the ones we don’t see that are really in danger.

“The ones that you see flying around are the lucky few that survived to that stage,” Davis said. “What you don't see are the dozens of deformed monarchs that are now crawling around on the ground, dying a slow death, because they never did get their wings. Now they can't fly, now they can't feed and they just sort of starve to death in your bushes.”

A pinky finger is holding up a wilted monarch butterfly.
Jordan Adams
The monarch butterfly infected with the parasite has crinkled and wilted wings as opposed to the full normal wings a healthy monarch has.

In the letter, Davis said people need to set their feelings aside and end their love affair with monarch butterflies.

“One thing that would help, at least in your backyard, is to remove your milkweed, i.e. all of it, the native, the non-native milkweed that people have,” Davis said. “Because if you have milkweed in your backyard in Florida you are now creating a hotspot of infection.”

However, not all scientists agree with Davis. Studies have shown that a loss of milkweed is one reason for the butterflies' decline.

Updated: April 25, 2024 at 3:37 PM EDT
This story has been updated to reflect that some scientists disagree with Andy Davis' call to remove milkweed from yards.
Kayla Kissel is a WUSF Rush Family Radio News intern for spring of 2024.