Hypothesis on Commas and Currants

Michael Gochfeld gochfeld at eohsi.rutgers.edu
Mon Oct 19 08:16:32 EDT 1998

	I would appreciate comments as to whether the following makes 

A century ago the Gray Comma (Polygonia progne) was never common in New 
Jersey, but was apparently not rare within 50 miles of New York City 
according to Beutenmuller's 1893 [yes 1898] compilation. John B. Smith 
(1890-1900-1910) considered it occasionally common but local in northern 
New Jersey.  Comstock's 1940 work on the butterflies of New Jersey 
considered it "not common", listing specimens from eight locations.  
Today the Gray Comma is very rare in New Jersey, if it occurs at all, 
with no records since the early 1980s. The Green Comma (Polygonia 
faunus) was even less common than the Gray a century ago, and is also 
"gone" from New Jersey if it was ever resident. 
	In our book on the Butterflies of New Jersey we speculated that 
these might have been one of the victims of pesticide spraying. However, 
we overlooked another important factor.  The Gray Comma's primary hosts 
in the east are Wild Gooseberry (Ribes rotundifolium and other species 
of Ribes:gooseberries and currants). It rarely uses elms such and also 
White Birch. The Green Commas also uses Gooseburry and Currants as well 
as a few other hosts. 
	The Gooseberry and Currants happen to be the alternate hosts of 
the White Pine Blister Rust, a fungus which devastated White Pines in 
the early 20th century (one of our most important timber trees).  As a 
control effort the Federal Government sent workers through the 
countryside (including peoples private yards and farms) to eradicate 
these plants. The period was 1910's probably into 1930's. The intention 
was total eradication of these wild plants (I presume the garden 
varieties were to be spared).  I haven't yet looked for reports on how 
thorough these teams were, but this "surgical strike" on the habitat may 
have had a hand in eliminating these two species. This would have been 
compounded by the Dutch Elm Disease which wiped out most American Elms 
in the 1950's and 1960's. Thereby denying Gray Commas any suitable host. 
	I would appreciate suggestions as to whether this makes sense.  
Also have these commas declined elsewhere?  
	There was also a War on wild Barberries (Berberis) which are the 
alternate host of Puccinia graminis, a cereal rust.  The fact that White 
Pine Blister Rust was brought under control antedated widespread use of 
synthetic pesticides and is in stark contrast to ineffective eradication 
 of "insect pests" by chemicals. But that is another story. 

M. Gochfeld

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