Another tidbit from The Dangerous World of Butterflies:
[Elliot Malkin of Brooklyn, NY] worries that migrating Monarch butterflies, in search of their plant food milkweed, will find a dearth of the needed vegetation in the urban reaches of New York City. Intent to do what he can to help, he placed potted milkweed plants on the balcony of his apartment. Concerned that it might be difficult for the butterflies to locate his few plants in the asphalt jungle, two ideas came to him: paint giant pictures of milkweed adjacent to the real plants to alert the flying Monarchs, and then paint them with sunblock.
“Milkweed flowers,” says Malkin, “have natural ultraviolet patterns that are recognizable to Monarch butterflies. These patterns are invisible to us because we can’t see light in the ultraviolet spectrum. So Graffiti for Butterflies uses sunblock to pain the graffiti in a way that mimics these natural ultraviolet properties.” Sunblock is a perfect medium, he says, because it reflects ultraviolet light. Malkin considers his work “the equivalent of a fast-food sign on a highway, advertising rest stops to Monarchs.”
Malkin can’t say conclusively whether his sunblocked paintings are responsible for attracting the butterflies to his rooftop garden, but they are indeed visiting his milkweed plants. Here’s Malkin’s website.
In other news, our milkweed is blooming.
(Photo of last year’s crop.)