And the Great Spangled Fritillary Who Actually Helps the Plant
In an earlier post on PubWages, “The Monarch Butterfly and the Thistle Flower”, I shared how I finally got good photos of a Monarch — but not on milkweed. It was on thistle instead. Meanwhile, I saw plenty of Great Spangled Fritillaries on the milkweed plants. That observation planted the seed for today’s deeper look at this relationship.
Monarch Caterpillars: The Leaf-Eating Specialists
Monarch caterpillars are famous for their exclusive diet of milkweed leaves. They consume the foliage and sequester the plant’s toxic cardiac glycosides for their own defense. This makes the Monarch a superstar in the eyes of conservationists and gardeners — but from the milkweed’s perspective, it’s a heavy consumer.
Adult Monarchs do visit flowers for nectar (as seen in my older post on thistle), but they are not efficient pollinators of milkweed. The plant’s pollen comes in specialized sacs called pollinia that need to be extracted and inserted precisely — a task better suited to stronger, more robust insects.
The Great Spangled Fritillary: The Better Pollinator
Caption: Great Spangled Fritillary on milkweed. These butterflies provide a more balanced relationship with the plant.
As I noted in the thistle post, I observed many Great Spangled Fritillaries on milkweed, but never an adult Monarch on its “signature” plant’s flowers. Unlike Monarch caterpillars, Fritillary larvae feed on violets, not milkweed. When the adults visit milkweed, it’s purely for nectar — and their larger size and stronger legs make them much more effective at transferring pollinia.
This creates a win-win: the fritillary gets food, and the milkweed gets genuine help with reproduction.
A Tale of Two Butterflies
The Monarch brings the fame and inspires milkweed planting, which is wonderful. But as my own observations (and photos) show, the story is more nuanced. Milkweed thrives thanks to a diverse pollinator community — including the hardworking Great Spangled Fritillary.
Gardening Tip:
Plant milkweed to support Monarch caterpillars like the one pictured above. Add violets for the Fritillaries, and don’t be afraid of “weedy” plants like thistle that provide nectar when milkweed flowers are scarce. Or just let everything grow wild, and see what plants itself!
