|Washington County's first Wild Indigo Duskywing!|
On August 6, while making a phone call on the front porch of the NBNC offices, Chip noticed a small, dark insect fluttering around the driveway. He immediately recognized it as one of the duskywing butterflies, and after running to grab coworkers and camera, it was confirmed to be a Wild Indigo Duskywing… not just a new butterfly for the Nature Center, but a new species for Washington County!
Since an extensive butterfly survey was completed in Vermont in 2007, this is the fourth new species to be added to the Washington County checklist. Wild Indigo Duskywing may be new to central Vermont, but it was not unexpected. The native host plants of this species, Wild Indigo (Baptisia tinctoria) and Lupine (Lupinus perennis), formerly restricted the range of this species to southern New England. But in recent years, the Wild Indigo Duskywing has colonized the introduced species Crown Vetch (Securigera varia). Using this new host plant, the species has been expanding its range northward.
|West Virginia White|
photo by Tom Murray (bugguide.net)
While the Wild Indigo Duskywing seems to have benefited from an introduced plant species, many other butterfly species have suffered. One example is the West Virginia White. This species, active in early spring, uses toothwort as its sole host plant. But in places where the invasive Garlic-mustard (Alliaria petiolata) has been introduced, West Virginia Whites don’t recognize the foreign plant, and lay their eggs on Garlic-mustard rather than toothwort. The caterpillars, unable to feed on garlic-mustard, eventually starve.
Since the initial sighting nearly two weeks ago, Wild Indigo Duskywing has been seen on the property several more times. It seems that this species may be a new permanent resident of North Branch Nature Center. Keep an eye out for this nondescript butterfly in fields and meadows throughout central Vermont and submit your observations to help document the continuing expansion of its range.