Dr. Matthew Douglas, Professor of Zoology and Botany at GRCC, has recently published a paper in the Great Lakes Entomologist, a national peer-reviewed journal, that documents the change of nectar-providing plants used by migrating monarch butterflies (from goldenrod to the invasive Star Thistle/Spotted Knapweed) in the Beaver Island Archipelago of northern Lake Michigan. The paper is titled: Use of Spotted Knapweed/Star Thistle (Asterales: Asteraceae) as the Primary Source of Nectar by Early Migrating Monarch Butterflies (Lepidoptera: Nymphalidae) from Beaver Island, Michigan.
The paper suggests that as climate change progresses, migrating monarchs may be forced to switch to nectar plants that are blooming at the time of migration in August, even if these plants are invasive. In the Beaver Island Archipelago, the invasive Star Thistle is virtually the only plant that provides enough nectar for a long-enough period by monarch migrating to Mexico by the tens of thousands in mid-August. Such nectar-bearing plants are absolutely vital to the success of migrating monarchs, which take the sugars and convert them enzymatically to fat, which is more efficient to carry in large fat bodies during the migratory flight of over 2,000 miles to their overwintering roosts in Michoacan, Mexico.
And in positive news (per Dr. Douglas), “As a side note, the number of overwintering monarchs in Mexican roosts is nearly 5 times that of recent years, suggesting that there is hope for our rapidly disappearing monarch butterflies.”
Congratulations, Dr. Douglas!