I’ve noticed a growing trend in how we talk about milkweeds and monarchs, and I’d love to get some input from others involved with these groups. While I understand the concerns regarding Asclepias curassavica and the Ophryocystis elektroscirrha (OE) parasite it can host outside of its native range, I’m confused about why organizations like WWF are recommending the disuse of A. curassavica in Mexico. I think blanket generalizations like this deserve further discussion.
Specifically, I’m working with recommended species for pollinator gardens in the Yucatán Peninsula. Monarch butterflies here, as far as I can find, are resident species. They primarily lay eggs and feed on A. curassavica and a second, less common Asclepias species. A. curassavica also provides nectar to a variety of other native butterflies that aren’t susceptible to the OE parasite. While researching this, I’ve noticed that many Mexican experts and media outlets cite U.S.-based studies suggesting A. curassavica should be avoided for pollinator gardens. However, I’ve encountered a few points that leave me questioning this:
I haven’t found any studies that address OE prevalence in native A. curassavica or in resident monarch populations in the region.
In the Yucatán peninsula, A. curassavica tends to die off during the dry season, sprouting back only once the rains begin. This should reset the parasite accumulation process.
In its native range, the interaction between the parasite and host plant seems to be part of a natural selection process. The presence of OE is just another part of the ecosystem’s balance.
Additionally, A. curassavica serves as a host plant for at least 17 other butterfly species and 7 bee species (based on my research, and I’m sure further observation could add to this list).
I’d love to hear others’ opinions on this. I understand the importance of precautionary measures, and while there may be some merit to avoiding A. curassavica along migratory routes (even within Mexico), I feel that vilifying the plant throughout its entire native range might be overly cautious or even irresponsible.
Thanks! Hamelia patens is a beautiful flower, I’ve got some on my yard (native range) and the amount of hummingbirds and colorful bees I see on it is remarkable.
Great, I don’t know where to start from. I live in the Yucatan peninsula too so I’ve got a lot to say.
You just answered yourself. Blanket generalizations, that’s what it is. A. curassavica is by far the most cultivated species in the world, and, although the WWF is clearly generalizing, most of the places where this plant is present are not its native range and have lots of native alternative hosts. The Yucatan peninsula seems to be one of the few places where it truly grows wild (and mostly in disturbed environments).
Mexico is a very big country. In most Mexican big cities, where the climate is colder and less tropical, this is quite applicable. A. curassavica is not a plant that should be in these places but I’ve seen myself how extensively it is used as an ornamental.
I have absolutely no idea about the status of OE in the Yucatan peninsula. I had never considered its existence here. But I think you shouldn’t worry about that. A. curassavica seems to work well for monarchs, particularly because the presence of this plant is related to more weedy, wild areas, and not to very polished and embellished gardens where there’s no diversity and pests and parasites particularly easy.
But I suggest to you to use it in moderation. Where A. curassvica grows, there are dozens of other wildflower species useful for pollinators. Or simply let wild vegetation grow. That’s the best thing you can do for pollinators.
Another reason I suggest you to use A. curassavica in moderation is because it’s far from being the only host for monarchs in the area.
But in areas closer to the coast, in the wetlands, there are many other kinds of milkweed-like weeds (mostly vines) and at least two of them are Monarch hosts. Calotropis procera is also a host (although introduced) in some locations (more on that later).
Another reason for suggesting you to use tropical milkweed in moderation is for you to pay attention to all the extremely ignored plants that make the woods. I’ve seen the greatest diversity of pollinators on trees and shrubs when flowering in their seasons (now is a strong season for this). Or just go to some good secondary vegetation during the rainy season, close to a better preserved area, and observe which wildflowers are the most successful!
That’s not true. What I’ve observed (this is based only on my personal experience unless I specify the opposite) is the opposite thing. In fact, I’ve seen Monarchs on counted occasions, and it has been under a strict season frame. It has been in the month of March (and quite abundantly), or, I don’t remember if I’ve seen them in another month but definitely on March. Migratory movements seem to take place on March and on October-November. I don’t know anything else about Monarch migration other than this based on my experience and the experience of other observers, as well as iNat’s seasonality graph for the species in the region. Some maps I’ve seen on the internet include routes that pass by the Yucatan peninsula, proving migration in the region. The monarchs I’ve observed and have been photographed by other people have very large and wide wings with very long and falcate wingtips, adaptations that suggest capability of lengthy flights. I don’t hesitate there is a resident population, though, or that migration is something much more irregular. In Isla Mujeres, where Giant Milkweed is very common as an introduced species, Monarchs are very common too and easily seen. I can speculate that populations have become resident there in response to an abundant source of food, but this is only vague speculation.
‘‘We’’ have discussed enough about this already and I agree with that.
100% true. A. curassavica is very dependent on rain. I see they appear after heavy, constant rainfall.
I have studied this not at all. What you say should be true. But, is OE native to every place it inhabits? I doubt so. I don’t even believe OE is present in the Yucatan peninsula. Now I see how ignorant I am.
Maybe you meant nectar plant? Those are too many species at least for the Yucatan peninsula.
Then, I hope all this is useful for you. Try to include as much diversity and to observe which plants are the most successful. If you want me to talk about my personal experience with flowers and their visitor, I’m open to it and have a lot to say.
At the very least, it serves as a host plant for the other species of Danaus. There are three Danaus species in the State of Yucatan: the Monarch (D. plexippus), the Queen (D. gilippus), and the Soldier (D. eresimus). I call these the “Face Cards” because they remind me of the K - Q - J in a deck of playing cards. In the Dominican Republic, we have these three plus a fourth one, the Caribbean Queen (D. cleophile).
@sebastian_why the “second, less common Asclepias” – is it A. nivea? We have that in the Dominican Republic, and in some places, it seems to outnumber A. curassavica.