Crops found to make great monarch butterfly breeding habitat

Paul Cherubini monarch at saber.net
Fri Jul 13 02:39:25 EDT 2001


Mark Walker in Mason County, IL 7/12/01 wrote:

> it's amazing how much habitat is consumed by crops. 
> If we all love leps so much, we should probably stop
> eating.

> my [species] list: Danaus plexippus (Monarch) (doing very well here)

Mark, there is a good reason why monarchs are so abundant in areas
of the upper Midwest USA dominated by row crops - corn and soybeans
actually make outstanding monarch butterfly breeding habitat!

Yes, this was the stunning new finding reported by Dr. John Pleasants
of the University of Iowa, Ames, at the Monarch Research 
Conference in Kansas in May 20-23, 2001.

Dr. Pleasants and his colleagues estimate that 71% of the monarch
breeding population in Iowa is produced on milkweed plants 
growing as weeds INSIDE the corn and soybean crops. In
Minnesota that figure is 94%!  Roadsides and other non-crop areas produce
only 29% of the monarchs in Iowa and only 5% of those in Minnesota.

How can this be?  Well Dr. Pleasants found:

-  female monarchs "prefer" to lay their eggs on milkweeds growing
    INSIDE the crop canopy rather than on milkweeds growing along roadsides 
    or in other more natural, non-crop areas.  

-   Roundup herbicide treatments don't kill the milkweeds (growing within
     the corn and soybean crops) but just burn back the top growth which, in 
     turn, stimulates the growth of tender new milkweed shoots (from the living 
     underground rhizomes). It is these tender new shoots which are 
     favored as oviposition sites by female monarch butterflies.

-  fewer monarch parasites and predators may exist INSIDE the crop canopy
   as compared to more open, adjacent  natural areas.

-  the milkweeds growing inside the crops are more healthy and nutritious
    for monarch caterpillars due to the chemical fertilizer use.

So we can now rejoice that extremely intense agriculture and its associated 
heavy pesticide and chemical fertilizer use is actually good breeding habitat 
for the supposidly "endangered" monarch butterfly.

Iornically, the monarch conservation establishment has been preaching just
the opposite -that agricultural expansion threatens the monarch. For example this  
website http://MonarchWatch.org/conserve/index.htm says:

"Monarchs and their amazing annual migration are seriously
threatened by human activities, in both their summer and overwintering
sites. Many of these threatening activities hinge on the destruction of
good Monarch habitats. New roads, housing developments, and
agricultural expansion - all transform a natural landscape in ways
that make it impossible for Monarchs to live there."

Paul Cherubini, Placerville, Calif.

 
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