Nature Notebook – A Butterfly’s Favorite Flower

What is a butterfly’s favorite flower? Is a common question in our butterfly house. The answer, as always in nature, is…It depends.

In general, butterflies seem to prefer flowers that produce nectars that have relatively high sucrose concentrations. The concentration ranges from 20% to 25%. Ideally, the nectar would also have a good concentration of amino acids.

Two native plants, Sullivant’s milkweed (ascelpia sullivanti) and spotted bee balm (monarda punctate), have some of the highest sugar concentrations of flowers. They also fit the bill for what botanists call the “butterfly pollinator syndrome.” They have tubular flowers, proboscis guides, bright coloration and strong scents. The latter seems to be the most important in a butterfly’s search for nectar.

Although we are not permitted to provide milkweed in the butterfly house, the crimson-colored monarda was quite popular when it was in bloom. Now the coneflowers seem to be the nectar stars. When the jewelweed blooms, the sugary nectar (almost 30% concentration) inside their tubular flowers will have many visitors.

Some species of butterflies, like our Pipevine Swallowtail, can actually “learn” which species of flowers have the best nectar and will frequently return to them during feeding times.