Mexican Monarchs and Milkweeds

Nature Talk
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Hi fellow naturalists,

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:

  1. I haven’t found any studies that address OE prevalence in native A. curassavica or in resident monarch populations in the region.
  2. 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.
  3. 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.
  4. 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.

What do you all think?

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It is not a plant with which I am familiar but I wanted to say welcome to the forum.

(I am generally a wild fan of plants considered “malezas”, my favorite being Hamelia patens which I wish every garden could enjoy.)

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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.

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