Mona Miller wrote:
> http://www.learner.org/jnorth/images/gr ... 70897.html
> in 1997 they were there in March in the A. syriaca zone.
Paul Cherubini wrote: In March 1997 no monarchs were reported in the syriaca zone until March 27 when one was seen in Tennesee and then a few more were seen March 30:
So in 1997 the first eggs were laid around March 27-30 instead of April 6-8 like this year. So that would knock the dates the adults emerged from their chrysalids back to the 2nd week in May instead of the 3rd like this year, but a May 10 emergence date is still too late to have them show up in Lincoln Brower's Sweet Briar, Virginia yard during the period May 5-18, 1997. Plus Lincoln didn't say he saw any newly emerged brightly colored monarchs.
Therefore Lincoln Brower is justified in assuming that 28 of the 29 faded and worn monarchs with the syriaca cardenolide fingerprint he caught in Sweet Briar, Virginia May 5-18, 1997 had remigrated from the overwintering sites in Mexico. Paul Cherubini El Dorado, Calif.
Continuing a debate of a story that is always half told with significant points left out:
http://tech.groups.yahoo.com/group/west ... ssage/3701
The rest of the story can be found on the Western Monarch List Serve (just scroll down, if you are interested).
First, look at the map for Asclepias syriaca, it is locate almost at the bottom of the web page:
Maps of county locations of Asclepias in the United States
Are these all the locations of A. syriaca? No, they are not. There are patches of common milkweed in almost every gulf state, except Texas and Florida. Many, many sources have been selling seeds for ages. Many, many people have been planting them for Monarchs.
Second, this was Journey North's first year and your url that you posted didn't even take people to the data.
http://www.learner.org/cgi-bin/jnorth/j ... ?891885033
3/26 in NC
But, considering this is Journey North's first year I would suspect that all the Monarchs flying through the south would not be posted to the sightings. I think the same thing is happening now. Not all the Monarchs flying through the south will be posted to Journey North.
I do agree that there are Monarchs coming from Mexico in April through May and this was documented by a Mexican tagged Monarch being found NY. Source: Dr. James Scott, "The Butterflies of North America, A Natural History and Field Guide", look on page: 231.
But, there are just too many variables from year to year to assume that most of them came from Mexico by using cardenolide fingerprinting (chemical signature). Why don't I think that most of them came from Mexico? I think this because there are several locations along the gulf coast and other east coast areas where Monarchs are known to over winter. This also varies from year to year depending on how cold it gets in the winter. There is also time for Monarchs to finish a first cycle on common milkweed further south and get to Virginia by May 5-18.