The Mystery of Monarchs

January 10, 2016  •  Leave a Comment

Monarch with caterpillar on MilkweedMonarch with caterpillar on Milkweed Migrating monarchs generally head north in March or April, depending on the weather. Shadows move across the milkweed in my garden and as I notice a monarch laying an egg on the milkweed, I wonder if this is a resident or visiting butterfly? Not all of the six species of monarch butterflies migrate, and the ones who do still puzzle scientists. How can this beautiful fragile critter with a four-inch wingspan and weight of less than two one-hundredths of an ounce flutter 25-30 miles per day? The monarch has a sun compass in its antenna to orient it south in the fall. They also have a magnetic compass to orient them on cloudy days.

The Monarch’s journey takes the skill and cooperation of generations

In this region of North America, migratory monarchs travel up to 3,000 miles, from Canada to Mexico. Monarchs fly 25-30 miles per day, and they typically live from two to six weeks. Migrating butterflies tend to live longer, and the longest recorded lifespan of a monarch in Fort Myers, Florida is 84 days. So one monarch can’t live long enough to cover that length of a journey, which has become more dangerous in the past two decades. In the mid-1990s monarchs numbered one billion; that number is down by more than 90%.

It takes several generations of monarchs to make the journey; the monarch butterflies leaving Mexico this month are the great grandchildren of the ones that left Canada last Fall. How do they communicate this path to their offspring?  Before they die, monarchs lay eggs on milkweed. Monarch caterpillars require milkweed to grow, become a chrysalis and blossom into a butterfly that can continue the journey.

Magnificent stages of a monarch butterfly

Butterflies lay white eggs about the size of a grain of salt on the undersides of milkweed leaves.  After four days, the eggs hatch and the caterpillar eats milkweed for two weeks or so until it forms a chrysalis.  After 10-14 days, the chrysalis changes in color from green to dark gray and just before hatching, the wings of the monarch are visible. In the morning, a butterfly emerges and lets its wings dry out, so it can fly to nectar flowers.

Threats to the monarch

          Milkweed loss is a problem across the country, where the herbicide glyphosate, more commonly known as Roundup, has destroyed acres of native plant habitat. Without milkweed, monarchs can’t survive their journey. Other threats include illegal logging in Mexican forests where monarchs winter, and extreme weather, such as droughts, storms, unusually cold springs, pesticides, and increased housing development. The U.S. Fish and Wildlife Service is currently considering a petition to list the monarch butterfly as a threatened species.

          How you can help

            Planting native milkweed alongside nectar plants can help fuel monarch’s flights. Spanish needles and scorpion tail are two local native plants that provide nectar for monarch butterflies.  Avoid pesticides, especially systemic insecticides that will poison caterpillars and butterflies that feed on the leaves.

If you are interested in volunteering to tag and track butterflies, check out the North American Butterfly Association (www.NBA.org), which has local chapters in Florida. To encourage more butterfly gardens, the National Wildlife Federation has created a program called “Butterfly  Heroes” to inspire people to plant a butterfly garden, and will send families a Butterfly Garden Starter Kit while their supply lasts. People who pledge to start this garden by May 15, 2015 can win a trip for 4 to Walt Disney World (www.nwf.org/Butterfly-Heroes/Pledge.aspx).

 Noticing a beautiful orange and black creature fluttering about my yard brings me joy. But the monarch’s bright colors are not for beauty alone; those colors warn animals that a monarch is harmful to eat, so predators leave it alone.

Can we protect this natural wonder that is now in jeopardy? Fifty-two members of Congress recently supported listing the monarch butterfly as threatened under the Endangered Species Act.

 

 


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