by Mary Ellen Noonan
Every year monarch butterflies migrate thousands of miles to overwinter in Mexico, returning to the United States each spring. Since the discovery of their overwintering location deep in the Mexican forests in the 1970’s, scientists have been studying and counting their numbers. This year, however, their numbers are frightening low.
Scientists are not sure exactly what may be causing this drop in numbers. Over logging of the old growth Mexican forests, changes in climate, reduction in habitat, genetically modified crops and the dwindling supply of the milkweed plants worldwide are all possible reasons.
One thing we can do in our own backyards to help the monarch butterflies is to plant milkweed. Milkweed is the only food source that the monarch caterpillar eats, so ensuring it is found abundantly can greatly help the cause. Once found plentifully in fields and along roadsides, this native plant has been removed to make way for development, farming and more conventional landscapes.
Monarch butterflies aren’t the only insect that depends upon the milkweed. There is an entire community of insects that use the milkweed as their food source. Substances in the milkweed contain a mild poison, so insects that eat the milkweed taste unappealing to predators. Many of the insects in the milkweed community also have the noticeable bright orange/red/black color combination. These colors warn predators to stay away, with the added benefit of being a beautiful display in our backyards.
Milkweed seed is available from many native seed growers and, once established, grows by underground runners. Runners can be dug up and divided, easily shared with neighbors and gardening friends.