8-year study of nectar plants for butterflies for peer review

The study by Susan Dunlap with Aerulean provides a review of over 12,000 curated nectar plant records. It also includes detailed information on monarchs and Asclepias, an assessment of "Keystone" and dominant nectar plants, as well as numerous suggestions on how to leverage the data for the development of butterfly habitats.  This energetic study points out some already understood observations such as favorite native perennials for butterflies, but also uncovers nectar preferences of butterflies not known before.

“A review of the Dominant Genera shows that Asteraceae is the commanding plant family with 40.52% of the records, followed by Verbenaceae at 10.94%, and Lamiaceae at 6.81%. The “Keystone” Genera embody low plant diversity numbers with an extremely high yield of US butterflies attracted to feed. The “Keystone” Genera (in order) are: Asclepias, Cirsium, Lantana, Verbena, Salvia, Symphyotrichum, Bidens, Zinnia, Trifolium, and Eriogonum. The “Keystone+” group adds (in order): Buddleja, Conoclinium, Verbesina, Taraxacum, Echinacea, Centaurea, Solidago, Liatris, Chromolaena, Monarda, Rudbeckia, Phyla, Gaillardia, Heliotropium, Pentas, Vernonia, and Helianthus. These genera contain 1082 species that grow in the United States. The diverse growth forms of these taxa include: 496 annuals, 114 biennials, and 2585 perennials.

It is noteworthy that Asclepias, the monarch’s host plant, dominates the favorite plant list for both the general butterfly population and monarchs themselves. Very few individual taxa have such broad appeal and consequential conservation effectiveness. It is reasonable to consider that the sustained conservation effort mounted on behalf of monarchs has contributed to the general appeal of Asclepias to a great many US butterflies. As such, it serves as an affirmation of what dedicated and sustained conservation efforts can achieve. “ Read the full study here