Monarchs and Monoculture in southern Michigan

[Paul Cherubini]

Robert Dana wrote:

> Anyone have any data on the number of monarchs tagged
> by state? It's hard to interpret the data on numbers of  
> [tag] returns without this.

Dr. Chip Taylor has the data on the number of monarchs
tagged by state. Although Dr. Taylor has been very willing
to tell us the number of tag recoveries in Mexico by state,
he has not published (as far as I'm aware) the number of 
monarchs tagged by state to begin with.  

However, I can tell you that a much higher percentage
of the monarchs tagged in the corn / soybean belt of
the upper Midwest (Minnesota, Iowa, Nebraska, Wisconsin, 
Illinois & the Dakotas) are consistently recovered at the
overwintering sites in Mexico as compared to monarchs 
tagged in the eastern Great Lakes States, New England or 
the Atlantic coast.  This trend has been evident both before and 
after the widespread adoption of these crops by 2001.

In other words, the States that now have the most intensive
monocultures of BT corn and Roundup Ready soybeans
are still the States that produce monarchs that are the most likely
to successfully complete the journey to the overwintering sites 
Mexico.  

Paul Cherubini
El Dorado, Calif.

 
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