Monarch Kill Comments?

Paul Cherubini cherubini at
Mon Sep 4 23:25:57 EDT 2000

Cris Guppy wrote:
> Paul: how do you know it is trivial? Or that there were only a few thousand
> dead Monarchs? If a street sweeper was used to clean up those on the roads,
> tens or hundreds of thousands seems more likely.
 > Also, how many other towns are spraying for mosquitos in Minnesota? If a
> hundred towns are spraying with similar effects on Monarchs, then the "few
> thousand" becomes a "few hundred thousand", or a million or more.

Gaylord, Minnesota has less than 5,000 people and thus a very small
area of tree cover. Only those monarchs hanging in trees above city
street and fogged at close range would get killed and then only a portion
of them. The vast majority of the monarchs in the city would be expected
to survive because they would be clustered in situations out of the direct
path of the fogging machines (i.e. in backyards, city parks, cemeteries, etc)
Also, monarchs stay in Gaylord and other Minnesota towns for only 
a week before moving south into Iowa.

Below is another report from another Minnesota town of great numbers of 
monarchs this year:

Judy Westegaard wrote yesturday on the dplex-list:

> To whom it may concern:  I  live in Windom, MN, and my backyard is
> directly in the migration route this year.  Hundreds began appearing
> approximately 5 days ago and this afternoon, they are in the thousands.
> We can literally stand in clouds of butterflies in our yard.

> Windom, Minnesota, US
> County: Cottonwood County
> Location: 43:52:10N 95:07:06W
> Population (1990): 4283
> Elevation: 1364 feet

                    =         640 square miles
                    =  409,600 acres
Corn            =  178,000 acres = 43% of the County land (1999)
Soybeans     =  173,300 acres = 42% of the County land (1999)

An amazing 85% of the land in Cottonwood County is planted
is corn and soybeans. This ultra monoculture which includes about 30%
genetically modified corn (Bt corn) and about 55% genetically modified
soybeans (e.g. Roundup Ready soybeans) has supported a population
explosion of monarchs this year. The monarch caterpillars do not eat
corn and soybeans, but feed on milkweed plants that are abundant
along roadsides, hedgerows, and at the edges of the crops.

Today on dplex-list Jerry Wiedmann wrote:

> Rock County Minn which includes Blue Mound State Park and
> Luverne MN was checked by me for the last 4 years on July 4 NABA 
> butterfly counts.  This year I had 58 on July 12, last year 49 on July 7.
> In 1998 I had 16 on July 4 and in 1997 I had 13. 

> Blue Mound is loaded with Milkweed but so are the
> Soybean fields and roadsides.  Pauls numbers for corn/soybean 
> production seem reasonable from my memories of driving through 
> the countryside.  Monarchs clearly thrive in a monoculture environment 
> that will drive other species to extinction.

                   MONARCH      Bt CORN         GM SOYBEAN
                       COUNT       ACREAGE         ACREAGE
                                        (% of total corn   (% of total soybean
                                               acreage)               acreage)

July   4, 1997:   13 monarchs      9%                10%
July   4, 1998:   16       "            26%                27%
July   7, 1999:   49       "            30%                47%
July 12, 2000:   58       "            28%                56%

Luverne and Blue Mound State Park are located in
                          =         483 square miles
                          =  309,120 acres
Corn                  =  130,500 acres = 42% of the county (1999)
Soybeans           =  124,600 acres = 40% of the county (1999)

It's probably a just a random, biologically meaningless coincidence, 
but mid-summer monarch counts have been rising in southwestern 
Minnesota for the past four years as the percentage of land planted 
in Bt corn and genetically modified soybeans has been increasing.

Paul Cherubini

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