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  • Andy Davis

An open letter to Florida monarch-lovers, from a monarch scientist



Hello Floridians,


If you are reading this blog post, then someone must have shared it with you, or shared it to a group you are part of, perhaps because you are someone who lives in Florida and loves monarch butterflies. I'm a scientist at the University of Georgia who has been studying monarch butterflies for 25 years, and I have some very important things to share with you about the current situation in Florida, as it pertains to monarchs.


I'm going to get right to the point - you Floridians are not helping the monarchs as much as you think you are, and in fact you are probably causing considerable harm. I know this sounds harsh, but I want to get your attention so you will listen. In fact, make sure you pull up a chair and read this post thoroughly, without skimming. If you truly want to help the monarchs, you owe it to them to do the right thing, or at the very least, hear me out.


You need to be aware that right now, monarchs across most of the state of Florida are heavily infected with a debilitating parasite (Ophryocystis elektroscirrha, or OE) that weakens the infected butterflies themselves (if they live to their adult stage), reduces their lifespan, and it is now spreading into the rest of the N. American population, and hindering the famous migration to Mexico. This is not the way it has always been in Florida, and it is really a situation that has arisen in the past 20 years because of people like yourself who have been trying to help the monarchs there, but have been guided by misinformation or just plain no information. That's right - this situation is mostly because of you, or to be more specific, because you did not get the correct information or guidance. This is why I'm writing today.


Let me start with this parasite, which is now overrunning the Florida monarchs. This parasite cannot be seen with the naked eye, and many infected butterflies look perfectly normal. You probably have some infected monarchs in your yard right now. Don't let anyone tell you that "their monarchs are fine," especially if they don't own a microscope and never checked them. You can't tell if a monarch is infected just by looking at it, or, by the condition of its wings, or the size of the caterpillar stripes, or any other urban myth you've heard. Most of that is just wishful thinking, or just plain misinformation. Infected monarchs can fly around and visit your backyard milkweeds, looking like normal monarchs - these are the ones you are seeing in your yards right now. Keep in mind that each milkweed that they touch (or even hover over), gets contaminated with the infectious spores of the parasite, which then get eaten by the hungry caterpillars, thereby perpetuating the cycle. There is a link to more info about this parasite later in this post. For now, know this - Florida's monarchs were not always infected with this parasite, and this current situation is not "normal" for Florida. If someone told you something otherwise, it is because they were misinformed. Historically, most of Florida's monarchs were seasonal, just like everywhere else in the N. American breeding range. And, most of Florida's monarchs were uninfected, historically. There is a link to a paper below with more info on this.


Nowadays, all of Florida's monarchs are heavily infected, and are now present all year, largely thanks to people in the state just like you. Thanks to people planting lots of milkweed, especially non-native milkweed, which encourages year-round residency and winter-breeding, which is the perfect recipe for heavy OE infections. Tropical milkweed has exploded in Florida over the last 20 years, and this is also a new thing. People have been buying this (or other non-native) milkweed, thinking that they are helping the monarchs, but in fact, these non-native milkweeds do the opposite. The non-native milkweed allows the parasite spores to build up, leading to more infections, and so on. Unfortunately, the situation is now beyond the non-native milkweeds too. Since nearly every adult monarch in Florida is infected now, that means that every milkweed that gets visited (native or non-native) will then be contaminated. You may have heard that you can "fix" this by cutting back your milkweed, but that is just wishful thinking. Research has shown that cutting milkweed back does not lower OE prevalence in a situation like this. It will just be re-contaminated as soon as the next monarch comes along, which will be pretty much every day.


The other thing that is really, really not helping is people who raise monarchs in captivity in Florida. This may be you, or someone you know, and I'm sure you or these people think they are helping, but again, this practice is not based on science, and it is really just a feel-good activity. You need to be aware that rearing monarchs in captivity amplifies the OE parasite in the population. In Florida, since the OE parasite is on all milkweeds, it will simply transmit to most or all of the caterpillars in captivity, so that you will end up releasing more infected monarchs. Even if you (or someone) washes and bleaches all of the milkweed leaves used in the rearing, and takes precautions to only raise OE-free monarchs, releasing these adults anywhere into Florida will also not help. Those (healthy) adult monarchs you released will go on to lay their eggs on the OE-laden milkweed that is everywhere in Florida, thereby producing more infected monarchs. So, regardless of whether or not you bleach, or even test "your" monarchs for OE, rearing monarchs in Florida is adding to this problem.


Here's the crazy irony to this whole mess - the number of monarchs in Florida was never in decline, and in fact they have been increasing in recent years. There is a link to a recent study that confirms this below. This population increase is both good and bad. It means that there was never a lack of habitat for monarchs in Florida, nor was there any need for people to step in and "save" them. But, this also means that now, we have an increasing number of highly-infected monarchs in Florida! It is akin to inflating the number of FIV-infected feral cats in a neighborhood by providing the cats with food and shelter, thereby allowing their (infected) population to grow.


I know this is a lot to take in. So, if you are still reading, I'm going to make a list below of things you really can do if you want to help the monarchs in Florida.


You're not going to like this first (and most important) recommendation - the OE situation in Florida is now so out of control that I'm actually recommending that people in Florida remove all of their milkweed in their own yards - both native and non-native. Yikes! I know this sounds crazy, but that's how bad it's gotten now. Now I know that native milkweed in Florida will die back at some point late in the season, but keep in mind that by then, it will have helped to produce yet more infected monarchs all summer. That's right, your native milkweed is now exacerbating the situation in Florida. So, I call this the "sleep better at night" option. Keep in mind that by removing all of your own milkweed, you won't possibly make a dent in the overall Florida situation, but, you can sleep better knowing that your yard is not adding to the problem. Note - I'm not advocating that people remove any native milkweed that is growing wild, only those you planted in your yard. If it makes you feel better, you can switch to just providing nectar sources for monarchs. That will still be helping them, but at least you won't be contributing to new infections. I know full well that this recommendation is very, very hard for people to accept, and after hearing this, you may find yourself searching the internet for possible counter-articles to post in your facebook group too. I'm sure you can also ask around and find some other person with "expertise" who will tell you what you want to hear too (i.e. to keep doing what you want), but I can tell you now, they don't know the situation, the OE, and the monarch research like I do.


Next, keep in mind that you are in this mess because of misinformation, and, you may have even contributed to this yourself without knowing it. So to reduce this, please stop offering advice or comments about monarchs, milkweed, or the parasite to each other in your facebook groups if you don't really understand the science, or haven't even read it. Facebook is the place where misinformation is spreading the fastest, by well-meaning strangers trying to give advice based on "what they heard from someone", or based on their own misinterpretation of the research. I've seen the Florida-based groups. I've seen the comments. It is a mess. I know you were just trying to help, but if you give someone bad advice, you are actually doing more harm than good, and helping to create the debacle you're in.


Similarly, watch where you yourself get your information about monarchs, or milkweed, or the parasite, etc. Ask yourself if the person giving you advice is an actual expert, or do they just say they are (i.e. if they call themselves "BobTheMonarchGuy" or whatever). One surefire way to tell if the advice is sound is if there is any science being referenced. If not, then it is probably just an opinion. Keep in mind that any nursery that sells non-native milkweed is going to tell you it is fine to use. There's an old saying, you never ask a barber if you need a haircut. In fact, most "native" nurseries will probably want to sell you their native milkweed too, and tell you that the natives "don't have the OE issue", which is not true.


I'm sorry to be the bearer of bad news here, because what I'm basically saying here is that people in Florida need to give up their love affair with monarchs.


Below are some handy links to science and/or data that backs up everything I have told you, and where you can click to learn more. I'm also including links to two different zoom session recordings where I have given presentations on the situation in Florida, and where I go into even more detail about these issues. If you truly wish to help the monarchs, please do read these, or watch the videos.


Zoom discussion with Miami Zoo butterfly expert, in 2022 - https://www.youtube.com/watch?v=T1NI9vT-b6k


Zoom discussion about monarchs in Florida, March 2024 - https://www.youtube.com/watch?v=sOPZPN2kE6Y


Source for more information about the OE parasite - www.monarchparasites.org


Link to prior blog describing the growing threat of the OE parasite in N. America - https://www.monarchscience.org/single-post/monarchs-have-a-growing-parasite-problem-and-it-s-not-from-natural-causes


Review paper by Dr. Lincoln Brower, where he discusses the history of monarchs in Florida - https://images.peabody.yale.edu/lepsoc/jls/1990s/1995/1995-49(4)304-Brower.pdf


Link to study that shows increases in monarch population in Florida - https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16282


Finally, if you wish to educate yourself with the real facts about monarchs (not just as they pertain to Florida), feel free to join my own Facebook group, "The Thoughtful Monarch," where I post daily updates or summaries about actual research and science around monarchs - https://www.facebook.com/groups/565065511941624. This group was created with the goal to reduce the spread of misinformation around monarchs! By joining, you can be part of the solution. Many of the members of the group are former monarch-rearers too, who now realize they had succumbed to the misinformation!



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2 Comments


Virginia Chong
Virginia Chong
3 days ago

With all due respects to the scientific information presented, as someone with a science background, I am going to offer a counter viewpoint. If the Florida population is non-migratory and as of yet, not cross-contaminating the other two populations (West, East), then the focus should be on the protozoa (natural or man-made controls), and at best, a Northern FL panhandle barrier. South Florida is pest control central. If the non-migratory, South population is heavily infested but doesn't interfere with the other populations, then gardeners and nurseries are only promoting and nurturing flawed and short-lived, somewhat sickly insects. The amount of environmental care, hobby gardening, and personal enjoyment outweighs the risk of overbreeding contaminated butterflies that are not doing harm to…

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vickiewilson
3 days ago

Your article made me feel very disheartened and guilty.

However, I believe you, and I will comply. It all makes sense to me and what I have witnessed in the butterfly refuge I’ve built adds to my willingness to cooperate.

Thank you. Tell the monarchs I’m sorry. I’ll be planting more plumbago.

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The science of monarch butterflies

A blog about monarchs, written by a monarch scientist, for people who love monarchs

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