Near the end of June Michelle and I took a trip out to central Wisconsin to visit the Necedah National Wildlife Refuge. Necedah NWR is located about two hours east of the Twin Cites and is known mostly for the Whooping Crane project which teaches young, captive raised, whoopers to migrate south through the use of an ultra light aircraft. However most of the whooper action takes place in the fall. Our main purpose for this visit was to try and photograph the endangered Karner blue butterfly.
The Karner blue is a sub-species of the Melissa blue, a blue butterfly that is fairly common and widespread through out the western United States. The Karner blue is found only in isolated pockets in the Great Lakes region, including the states of Minnesota, Wisconsin, Indiana, Michigan, and New York.
The issue with the Karner blue is the dependence of the the larval Karner on the wild lupine plant. Lupine is a wild flower that grows in sandy soil in open clearings, like pine barrens and oak savannas. Because of development and fire suppression, wild fires prevent the encroachment of woods and help to open up space that the lupine needs to grow, there is less lupine growing out in the wild.
The Karner blue in its larval, caterpillar, stage exclusively eats the wild lupine leaves. So as the amount of wild lupine decreases so does the number of Karner blue butterflies. Karners are no longer regularly found in Iowa, Illinois, Pennsylvania, Massachusetts, Maine, or Ontario where there were recorded populations in the past.
There is usually two broods of Karner per year. The first brood hatch from their eggs in April, the eggs are laid by the second brood of the prior year. They have 4 larval stages, instars, before they pupate, form a chrysalis. They usually take flight between the middle of May to the middle of June. The lifespan of the adult butterfly form is only about 3 to 5 days. During that short time they need to mate and the eggs which will become the second brood. The second brood usually takes flight between the middle of July to the middle of August. The second brood then lays its eggs which overwinter and hatch the following April to become the first brood of that year.
Although there are different places in Wisconsin, including Crex Meadows, Necedah NWR has the largest know population in the world. When we visited in late June I expected to see fields filled with blooming lupine, like I was seeing at Dodge Nature Center, but the lupine that we found seemed to be growing in patches mixed in with other wild flowers and grasses. Despite this fact we still managed to find several Karner blues. Karners are difficult to find, identify and photograph because like most of the other blues they do not get to be very large, their wingspan is usually only around one inch.