Record Low Monarch population expected in Mexico this winter.

[John Acorn]

Paul,

Don't get me wrong-- I value your contributions and I like the skeptical
approach.  I just want to remind you, and others on the list that if indeed
"ladybugs" are to blame, the species involved is the super-common Harmonia
axyridris (the Multicolored Asian Ladybug) which has come to dominate the US
fauna since it was introduced for aphid control a few decades back.  It will
switch from aphid prey to alternatives (such as other insect eggs) more
readily than most of its native counterparts (which are now less common) and
is indeed an example of human disturbance of the environment.

John Acorn
----------
>From: Paul Cherubini <monarch at saber.net>
>To: leps-l at lists.yale.edu
>Subject: Record Low Monarch population expected in Mexico this winter.
>Date: Fri, Sep 13, 2002, 1:50 AM
>

>Monarch populations in the upper midwestern USA have been
>much lower than normal late this summer.  Experienced observers 
>have found only dozens of monarchs at traditional overnight clustering
>sites that normally contain many hundreds or thousands of 
>monarchs.  Thus it appears likely the overwintering
>population of monarchs in Mexico this winter will be at
>record low levels.
>
>The Mid-summer population of monarch adults in the upper
>midwest was only slightly to moderately lower than last
>summer. The cause of the late adult population crash 
>summer appears to be a high population of monarch egg and first 
>instar larval predators such as ladybugs, ants, spiders, lacewings, 
>etc.  Several observers including myself found very few large 
>monarch caterpillars in July & August in Minnesota because the 
>predation of monarch eggs and baby caterpillars was so high.  
>
>The weak monarch migration this fall and record low overwintering
>population in Mexico will undoubtedly lead to many frightening and 
>worrisome "this could be the end" type monarch horror story articles
>in the popular press. I predict some of the scientists authoring or quoted in 
>the articles will not talk much about the natural biotic or abiotic factors
>that could have led to the monarch population crash, but instead will try to 
>link the crash to human disturbances of the environment such
>as logging, urban sprawl, pesticide use, global warming, genetically
>modified crops, etc.  Rant:  Nowadays it is fashionable and financially
>rewarding to link the decline of butterflies to human disturbances as this leads 
>to a greater level of public fear and worry and hence larger grants and 
>donations for the conservation organizations.  
>
>Paul Cherubini
>Placerville, Calif.
>
> 
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