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Happenings in the insect world
Comments:
by Mona Miller
on October 10, 2022 at 7:33 PM
Tropical milkweeds really aren’t bad, matter of fact, they are beneficial and medicinal.
by Allen Buchinski
on October 11, 2022 at 7:04 AM
Unless I’m misreading, the initial word (“The”) in this sentence isn’t needed: The experiments need to be done to test the hypothesis that reproductive diapause is being prevented by climate change, specifically the increasingly dissonant seasonal information given by the daylength cycle, which is not changing, vs. temperature, which is.
by Liane
on October 11, 2022 at 5:32 PM
I feel like this article really captures the misguided singlemindedness of the pure nativists. Defining a native is difficult at best and most native purists rely on vague definitions from dubious sources, including nurseries from whom they demand natives. (E.g. Pink Muhly is native. Yes, it may be native to the SE, but only to coastal regions. It is not native to the Piedmont where it is planted en masse -- and does quite well.) What is a native where is still not understood by most folks; even the experts struggle with what is a native (time on earth or in a region? location? habitat?). It seems like many institutions are kowtowing to this movement rather than responding to its limits and what that means for dealing with climate change.  
 
Then come claims that native plants feed "local" insects better. Really? Where is the science backing this. Is it a difference in the chemical composition of "nectar"? Or the flower shape of this plant vs that? Or the time of observation of feeding (one day vs. the next, morning vs. afternoon). I've spent inordinate hours watching pollinators on asters, native-ish to Georgia (New England asters - are they really native here? unclear) vs. Japanese asters. The native bees love them all. They tend to dine off a single kind at a time. If you measured on Tuesday, it might seem they eschewed the native, but on Wednesday, they might cover the imported and ignore the native. What to make of it????  
 
One caveat to the article above. I view the citation to milliontrees.me with skepticism since the authors do not even seem to understand what the word "perennial" means, appearing to use it to distinguish between evergreen and deciduous perennials. This makes me doubt them as a valid source of information.  
 
Otherwise, yes, this banning of tropical milkweed (and discouragement to using it in places where it would be deciduous because of the alleged threat) seems to be an overreaction on the scale of one bird died from gorging on Nandina berries; thus Nandina berries are toxic to birds. T'aint so. (But invasive, well, that's a different issue.)
by Ray Eckhart
on October 12, 2022 at 9:21 AM
I don't think this objection on the negative effects of Tropical Milkweed to the metabolism of the migrating adults, explained by Dr. Andy Davis of the University of Georgia, is addressed in the OP article. Interested in learning more.  
 
>>This paper describes an experiment that was designed to test what happens to larvae that eat different milkweed species, and specifically, what is the effect of these milkweeds on the metabolism of adult monarchs. This is a very interesting question, which has not specifically been explored before, but has great importance for the long-distance migration of monarchs.<<  
 
https://www.monarchscience.org/single-post/larvae-reared-on-tropical-milkweed-become-adults-with-the-wrong-metabolism-for-migration
by Julie Schneider Ljubenkov
on October 12, 2022 at 10:49 AM
The science is clear. This non-native milkweed is not a harmful, exotic invasive plant. It should not be banned. Thank for for this valuable information.
by Mona Miller
on October 12, 2022 at 2:57 PM
Reply to Ray Eckhart:  
Andy Davis wrote his opinion to this research*. The reality is that tropical milkweed an exotic and showy milkweed a native had the same energy cost.  
 
*“Impacts of larval host plant species on dispersal traits and free-flight energetics of adult butterflies”  
https://www.nature.com/articles/s42003-022-03396-8  
 
I usually read the abstract and then the results. This is in the results: “Specifically, mean flight muscle ratios of adults produced by larvae reared on tropical milkweed A. curassavica (35.4 ± 2.0%, ? = 19) and showy milkweed A. speciosa (33.8 ± 2.2%, ? = 15) were significantly higher (cur-sul: P = 0.0008, cur-ver: P = 0.017; spe-sul: P = 0.01, respectively; see Fig. 1) than those of adults reared on prairie milkweed A. sullivantii (22.5 ± 2.2%, ? = 15) and whorled milkweed A. verticillata (24.2 ± 2.6%, ? = 11).”  
 
“Specifically, adults reared on A. speciosa had a significantly higher normalized RMR than those reared on A. sullivantii (P = 0.0075), A. verticillata (P = 0.0283), and A. syriaca (P = 0.0276), while those reared on A. curassavica had significantly higher normalized resting metabolic rate than A. sullivantii (P = 0.0181). These results indicate that in addition to energy expenditure during flight, larval milkweed host species affect the energetic maintenance costs of adult monarchs.”  
 
Looks like tropical milkweed isn’t as bad as people have been pushing.
by Elizabeth
on October 14, 2022 at 12:20 PM
We accidentally pulled all of our tropical milkweed out. Then we found out it wasn't so bad so we put it in. Then was the end of the season and we pulled it out again. Now it's been laying on the ground I'm going to try to put it back in again. This article was great to sort things out thank you
by Anthony Lorenzo
on November 14, 2022 at 8:45 AM
This "expert opinion" seems to be rubbish. First, Asclepias curavassica may have existed in the US since the 1960s, it only was widespread planted around 2000, with the massive campaign to encourage planting milkweed guided by Monarch Watch and other NGOs.  
 
Second, studies have demonstrated that Asclepias curavassica does in fact induce reproductivity....  
 
And other studies have shown rearing uninfected Monarchs (OE) on A. curavassica are smaller... making migration more difficult. These experts don't seem to have done even a minor review of existing studies in formulating this OPINION PIECE.
by Mona Miller
on November 15, 2022 at 12:36 PM
This is in reply to Anthony Lorenzo.  
 
There was just a discussion on the Monarch Watch email list that cleared up some misinformation with regards to tropical milkweed. Tropical milkweed doesn’t stop the migration. It is in the October thread, the thread starts with “This parasite…..” https://lists.ku.edu/pipermail/dplex-l/2022-October/thread.html  
I personally have used tropicals to raise Monarchs and have found that as a food it far exceeds the nutritional value of native milkweeds.  
 
I do know tropical milkweed, Asclepias curassavica has been around in FL since the 1940s and in the Caribbean since 1860s.  
 
Records on the CalFlora site, one for 1909 for San Luis Obispo [That's over 100 years, and only now is it being blamed for causing an OE outbreak.] OMG, back then there were tons of Monarchs.  
 
All the records: http://ucjeps.berkeley.edu/cgi-bin/get_consort.pl?dups=CDA5518%20SD239561%20UCR195997%20SD240828%20UCR235513%20UCR179772%20UCR194084%20UCR262010%20UC455085%20UC1313033  
 
1909 record: http://ucjeps.berkeley.edu/cgi-bin/new_detail.pl?UC455085&YF=0  
More Information: http://ucjeps.berkeley.edu/cgi-bin/get_cpn.pl?Asclepias+curassavica  
 
It is considered a cultivated plant and not naturalized.  
 
Probably some missionary brought it to CA, they took it to islands along the Caribbean and to New Zealand.  
 
I emailed Dr. Hunter at the Univ. of MI [involved in several research articles on OE], I really think considering that OE has many strains that unless they can identify which strains they are using and which ones are more lethal that they shouldn't be doing experiments and come up with generic results. Saying something is climate related, when it could be strain related or some other issue like another disease causing it to be more lethal. This is why I can't logically buy all this science at times. I see flaws in the experiments.  
 
Edith Smith at Shady Oaks Butterfly Farm had Nosema in her stock. She said that Nosema suppresses OE. I used to get stock from her to jump start my local population. After she emailed me telling me about the Nosema suppressing OE, I emailed back asking her whether that is what the stock she sent me had. I stopped ordering. I decided I was just jump starting diseases with butterfly breeder stock. This was back in 2007. I got caught in Dr. Lincoln Brower’s student’s survey on commercial breeders on OE. The grad student did a little sting as part of a graduate research project. Yes she did find several breeders shipping Monarchs with OE. I had ordered stock from Edith and then shipped some to a breeder in Charlottesville, VA. That breeder was supposed to give adults to Dr. Brower. The deal was that I would send her extra caterpillars. The caterpillars that I sent were 2-3 instar. Caterpillars don’t share OE between them. OE is contracted from the mother, environment (dirty cage or other equipment), or food. I learned a bit about OE. Dr. Brower and his wife Linda Fink were helpful sharing their results of those adults. Some had heavy OE. But, it only takes one spore to multiply to hundreds.  
 
Of course, Dr. Hunter also did research on the medicinal value of tropical milkweed attributing it to giving both Monarch parents and offspring a resistance to OE.  
Asclepias curassavica is the species of milkweed used in the study. It was tested against a native with high toxicity, Asclepias incarnata, Swamp milkweed.  
“Monarch butterflies appear to use medicinal plants to treat their offspring for disease, research by biologists at the University of Michigan and Emory University shows.” We have shown that some species of milkweed—the larva’s food plants—can reduce parasite infection in the monarchs,” said Jaap de Roode, the Emory evolutionary biologist who led the study. “And we have also found that infected female butterflies prefer to lay their eggs on plants that will make their offspring less sick, suggesting that monarchs have evolved the ability to medicate their offspring.” Few studies have been done on self-medication by animals, but some scientists have theorized that the practice may be more widespread than we realize.” Several criteria must be met in order to demonstrate that self-medication actually is occurring,” said U-M chemical ecologist Mark Hunter, who collaborated with de Roode’s group on the research. “In this study, all of those criteria were met, making it one of the first clear demonstrations of self-medication in an animal. In addition, it’s the first example of trans-generational medication, with the mother’s behavior benefiting her offspring.”’ https://michigantoday.umich.edu/2010/11/10/a7904/  
 
Tropical milkweed is native to Mexico and Central America. It is considered an introduced species in the United States. It dies back in the northern states, but is a perennial in southern states.  
 
https://www.cabi.org/isc/datasheet/7248 [current link]  
Invasive Species Compendium Asclepias curassavica  
http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?4469 [This link no longer works, but I had copied this information from this link.]  
“Asclepias curassavica  
Distributional range:  
Native:  
NORTHERN AMERICA  
Northern Mexico: Mexico - Baja Sur, Nuevo Leon, San Luis Potosi,  
Sinaloa, Tamaulipas  
Southern Mexico: Mexico - Campeche, Chiapas, Colima, Guanajuato,  
Guerrero, Hidalgo, Jalisco, Mexico, Michoacan, Morelos, Nayarit,  
Oaxaca, Puebla, Queretaro, Quintana Roo, Tabasco, Veracruz, Yucatan  
SOUTHERN AMERICA  
Caribbean: Antigua and Barbuda; Bahamas; Barbados; Bermuda; Cayman  
Islands; Cuba; Dominica; Dominican Republic; Guadeloupe; Haiti;  
Jamaica; Martinique; Montserrat;Netherlands Antilles - Saba; Puerto  
Rico; St. Vincent and Grenadines; Virgin Islands (British); Virgin  
Islands (U.S.)  
Mesoamerica: Belize; Costa Rica; El Salvador; Guatemala; Honduras;  
Nicaragua; Panama  
Northern South America: French Guiana; Guyana; Suriname; Venezuela  
Brazil: Brazil  
Western South America: Bolivia; Colombia; Ecuador; Peru  
Southern South America: Argentina; Chile [n.]; Paraguay"  
 
http://www.conabio.gob.mx/malezasdemexico/asclepiadaceae/asclepias-curassavica/fichas/ficha.htm#2  
“Origen y distribución geográfica  
Distribution in Mexico [historical records of a native plant]  
Is registered in Aguascalientes, Baja California Norte, Baja  
California Sur, Campeche, Chiapas, Colima, Guerrero, Hidalgo, Jalisco,  
Michoacan [state where the Monarch reserves are located], Morelos,  
Nayarit, Nuevo Leon, Oaxaca, Queretaro, Quintana Roo, Sinaloa,  
Tabasco, Tamaulipas, Veracruz and Yucatán (Villaseñor and Espinosa,  
1998).  
Immigration status in Mexico  
Native.”  
 
Tropical milkweed is native right across the border in CA and TX. Frankly both Monarchs and milkweed evolved over time to head north. Tropical could have over time evolved to transplant itself over the border naturally. Why can’t we label it as a naturalized or cultivated plant instead of invasive?
 
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