karner blue

Michael Gochfeld gochfeld at eohsi.rutgers.edu
Sat Feb 6 17:46:55 EST 1999

The larval host, Lupinus perennis, is not that widespread, and it is 
declining in certain areas of the Albany Pine Barrens.  One of the 
central areas where I used to find both Lupine and Karner Blue, is now 
almost completely devoid of both, although a few plants are growing 
among the grasses near a parking lot.  There are some experimental areas 
with exclosures designed to protect the lupine from grazing by deer. On 
two visits to this experimental site in 1997 and 1998, it didn't look 
like the Lupines were doing worse outside the exclosures than inside 

One of the reasons for the decline of the Lupine in the central area, is 
probably succession due to fire suppression. However, I suspect that the 
burgeoning deer population may contribute to its decline in some areas 
(my garden for example). 

Controlled burning would probably help the Lupine. Whether it would help 
the butterfly is another story.  One possibility is that after years of 
fire suppression you get a build up of litter so that the next fire that 
eventually does come through is much hotter, and kills lots of things 
that would have otherwise survived---perhaps the ants are in this 

However, there are several species of ants that tend Karner Blue 
caterpillars, and although the tended caterpillars have about twice the 
survival rate of untended ones (based on work by  Dolores Savignano 
who did a study of the Karner Blue and its ant associates in the Albany 
Pine Bush) ants are apparently not essential for individual survival. 
Another suggestion is that a series of warm winters with scant snow 
cover is at fault.  The Karner Blue---at least at Albany---overwinters 
in the egg stage, and itis possible that with inadequate snow cover the 
eggs desicate or otherwise succumb. Normally the eggs hatch in mid-April 
about the time that new shoots of Lupine appear. 

It's also obvious that many other Lycaenids are in trouble. The 
International Union for the Conservation of Nature has published an 
entire volume (edited by T.R. New, 1993) on "Conservation Biology of 
Lycaenidae (Buterflies). 

The research on this species has been done mainly by Cryan and Dirig and 
their students. These authors reported that between mid 1970's and 1989, 
Lupine had disappeared from 18 or 46 of their study sites, and many of 
the persisting stands had declined due to shading.

Although all of these factors may interact, I think that controlled 
burning is critical to survival of the species, although it will not be 
popular since the Pine Bush has become a mosaic of habitat fragments 
with residential and commercial properties interspersed. And, of course, 
development pressure continues to mount.   

M. Gochfeld

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