A few weeks ago someone asked the question, where have all the Monarch butterflies gone?
I didn't know.
Although I haven't been paying attention, now that it has been brought to my attention, the absence of the Monarch butterflies in my own yard is noticeable. When I was growing up we spent of our summers outdoors, and it seemed that the butterflies were everywhere. My friends and I chased them into the fields where they lived on milkweed plants, and we tried to catch them in nets we bought at the five and ten-cent store. We tried to get up close so we could examine the brilliant orange on their wings framed with lines of black that reminded me of the stained glass windows in our church. These were the big butterflies, bigger than the smaller Viceroy butterflies that look similar to Monarchs, the little white fluttering cabbage butterfly or the tinier yet, Appalachian blue.
In the past week or so, the question has been coming up more often, and last week, gardener and blogger Margaret Roach examined the subject on her website as well as her her weekly radio program and podcast at A Way to Garden (awaytogarden.com).
Curiosity got the best of me, so I decided to look up some of the references Roach gave on her website as well as a few other sources.
According to World Wildlife Fund, the number of butterflies to arrive each year to their hibernation colonies in Mexico has reached its lowest level in two decades. A survey carried out during the 2012-13 winter season by the World Wildlife Fund and Mexico's National Commission of Protected Areas, discovered a 59 percent decrease in the total area the butterflies occupy from the previous winter season. There is no way to actually count butterflies so the size of their hibernating colonies are used as a way to measure their populations.
This is cause for concern for those who monitor these numbers, particularly the Monarch Joint Venture, a partnership of federal and state agencies and other non-governmental organizations (monarchjointventure.org), as well as the Nature Conservancy (www.nature.org).
It was in elementary school where I learned about the spectacular migration of the Monarch butterfly. Traveling as far as 3,000 miles to hibernate over the winter in the mountains of central Mexico, these insects are fascinating because they were born here, probably in mid-August, and when they begin their journey south, they are going to a place they have never been. They just know they are supposed to go.
Experts believe their dwindling numbers aren't caused by just one thing. The loss of habitat is certainly one reason we aren't seeing many butterflies. As fields filled with milkweed are being cultivated and mowed for construction and highways, the butterflies are losing their normal way of life.
Chemicals are also contributing to their decline. The bacteria, Bacillus thuringiensis, or BT, used to kill mosquito larvae, doesn't affect the butterflies, but the sprays for adult mosquitoes can be fatal to many insects, including butterflies. Scientists also are looking at changes in climate, particularly extreme weather conditions, such as drought or cold, and especially if these events occur during the insect's migration.
But we can't take all the blame. According the Nature Conservancy, the butterflies' winter homes are dwindling because the mountains of central Mexico are targeted for new roads, housing developments and the expansion of agriculture.
There are some things we can do to help, such as to designate a portion of our landscape to a wild area where we can plant milkweed, which is the Monarch's primary food source, and other native wildflowers. There are several species of milkweed (Asclepias), including the common garden plant, butterfly weed, A. tuberosa and swamp milkweed, A. incarnata. Although they are not milkweed, Monarchs are attracted to the nectar of many native wildflowers, including Joe-Pye weed, thistle, ironweed and goldenrod.