This winter, in a garden in Hawaii, I was checking out all of the exotic plants, when I was astonished to see a monarch butterfly. It was gracefully floating around, as if it was the most natural thing in the world for such a butterfly to be on an island thousands of kilometres away from land. Seeing the perplexed look on my face, the gardener told me that the monarchs had been there for years, and even though they were an invasive species, she was quite delighted to have them.
But don’t monarch butterflies migrate? Vast numbers of these insects do an amazing migration across North America each year. In the spring, they fly north looking for young milkweed plants, and upon finding one, they lay their eggs and flutter off to die. When the young emerge, they munch away on the quickly growing milkweed. Then they metamorphose into a brilliant orange butterfly and head north with the advancing spring, to start the whole process over, all within a six week life span. Three generations make this trek north, and then the last generation makes the incredibly long flight back down to Mexico, to hang out with the other migrants in huge numbers up in the mountain forests of pine trees. We don’t know how they do it, since four generations do the trip, and it’s not like any of them have ever done it before.
The milkweed plant is a necessary part of the monarch butterfly’s existence. There has been a dramatic drop in the number of butterflies, and the major reason is that there are nowhere near as many milkweed as there used to be. Environmental groups have been strongly advocating for the preservation and the replanting of these plants to help the monarchs.
The insect and the plant are very much dependent on each other. The milkweed produces a milky substance containing cardiac glycosides, which can stop the heart of any animal brave enough to munch on the leaves – and which keeps it from getting eaten down to the ground by deer and other grazers. However, the monarch caterpillar eats the leaves without showing any ill effects. They don’t eat much of the plant, just enough to develop into a caterpillar. Later, the butterfly carries the same toxins, which it advertises with bright orange wings which declare: ‘Eat me and you will die.’ The butterfly sips the nectar from the flowers, giving it strength to continue on its journey, thus passing on pollen to fertilize other milkweed plants.
So how come I am seeing a migratory butterfly on an island without milkweed? Well, our milkweed plant, with its pods filled with downy streamers, is not the only milky plant. In fact, there are hundreds of different varieties of this plant under the asclepias family. Butterfly weed, which is a pretty garden plant commonly planted here in Ontario, is also a member of this plant family which monarch butterflies feed on. This butterfly and all of its kin that I was watching in Hawaii were clustering around a very pretty variety of Milkweed from Asia. It had been imported to Hawaiian gardens in the 1800’s for the beautiful fragrance of its flowers. No one remembers bringing monarchs as well, but they have been known to be blown great distances by storms. Well, this cluster of Asian Milkweed and its resident monarchs were certainly thriving. There were caterpillars eating and butterflies flittering at the same time, in a perpetual cycle of life, all in one isolated garden. It shows just how resilient both insects and plants can be, and it holds out great promise for the future survival of these beautiful, if poisonous, butterflies.
Jeff Scott is a former councillor for the City of Kingston (Countryside District), and has contributed editorial content local publications for a number of years. He continues to live, work and write in the Countryside district of Kingston, and runs his own blog, The Countryside View. Visit his Facebook page at www.facebook.com/jeffscottthecountrysideview to read more of Jeff’s content.