Gail wrote in recently about a late season monarch here in Ithaca in mid-October… below is her Q and my A.
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Hello Anurag,
I found your email by searching Monarch and Cornell. I just found a large Monarch outside here in Ithaca. I brought it in b/c it was on the ground barely moving. Is there anything I can do? I grabbed some nasturtium, calendula and borage flowers that haven’t completely died.
It’s so beautiful I’m desperately trying to save it. Why hadn’t it traveled south by this time? Sorry to bother you, but I saw that you are a Monarch expert (which is a wonderful thing to be) hoping for some help.
Also, when I found your contact info with your photo I recognized you from shopping at Greenstar. I’ve worked there for years. Thank you for any guidance,
Gail
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Dear Gail,
Thanks for your message, and please introduce yourself in case you see me in Greenstar 😉
I just today saw a spectacular monarch on the wing in the morning as well. Unfortunately, if they don’t leave the Ithaca area by mid-September, they don’t have much hope of making it to Mexico. To give you some context, this has been an amazing summer season for monarchs. If I had to guess, perhaps a billion butterflies were generated late this summer (across the whole continent east of the Rockies). Ithaca has been full of butterflies. This bodes well for increased numbers in Mexico. Especially in such good years for monarchs, there are always a lingering few that were either too late or didn’t get the migration cues. Please don’t despair, enjoy the butterfly in your home and don’t try to “help” this individual. It is all part of the natural process.
Part of this summer’s success was that precipitation and temperatures were such that milkweed grew very well and the climate was very well matched to what monarchs need. Unfortunately, as I have recently written about, it is unclear why monarchs are so severely in decline. If, as I have hypothesized, there is something broken with the migration itself (lack of floral nectar, too fragmented a landscape, pesticides) then numbers in Mexico may not be as high as we are hoping for based on butterflies in the Northeast and Midwest. Let’s see.
Again thanks for your interest. I will be giving a free public lecture in the Cornell Botanical Garden’s series on Monarchs and Milkweeds (Nov 7th, 7:30pm in Statler Hall on Cornell’s campus) in case you are interested.
All my best, -Anurag
Might it be a good thing that some monarchs have a internal clock that is “off”? Could be a population available to shift migratory schedule as the climate changes!
Anurag, I’m enjoying your blog. I have a couple questions. I heard that 90% of the Monarch butterflies in Mexico were fed on Asclepias syriaca as caterpillars. Do you have the science to actually test for that? The other thing is, if all the plants in the dogbane family priduce the same toxins then why don’t Monarchs use them as hostplants also, instead of just using the plants in Asclepiadoideae? Is there some chemical trigger or pheromone that attracts the adults and caterpillars?
Good questions. Yes, the science backs up the 90% claim (this is not my research, but it is spelled out in my book Monarchs and milkweed). The data comes both from milkweed chemistry (what is sometimes called the “cardenolide fingerprint” and also from stable isotopes). Yes, most plants in the Apocynaceae make cardenolide toxins, but they make a tremendous diversity of types, some of which the monarchs cannot handle. Furthermore, non-Asclepias-milkweeds also produce other toxins and may lack feeding stimulants. All very interesting, thanks for your questions!