A Puzzling Decline in Butterflies - San Francisco Chronicle 12/22/99

[Paul Cherubini]

Pierre A Plauzoles wrote:
 
> If the reporter truly believes that "there is no clear reason" for such a decline,
> he/she need only look at how much insecticide is sold every year and applied to
> our farmlands and cities.  The idea that insecticides are as "targeted" as the
> manufacturers claim may be true, but "non-target" species are affected whether
> they wish to believe it or not.

The article was about Prof. Art Shapiro's 28 years of monitoring
butterfly populations in the Sacramento Valley and adjacent areas of
northern California. Dr. Shapiro has never attributed "down" years to
insecticide use in the area, but instead to natural events like weather
extremes (e.g. the hard freeze in Dec. 1998 ). Similarly, Art  does not
attribute "boom" years in butterfly populations to human activities in
the region. 

The factors responsible for the boom and bust cycles of many species
(e.g. monarchs) are not known.

Paul Cherubini, Placerville, California