Our Natural World: Monarch Mania
Mar 17, 2019 06:26AM
By Erica L. Shames
The statistics surrounding the downward spiral of monarch butterflies is staggering. East of the Mississippi we rely on natural pollinators like the monarch butterfly for our food supply, taking the issue from one of conservation to survival. We each have a role to play in welcoming monarch butterflies into our world. Can you help?
According to the Xerces Society for Invertebrate Conservation, a 30-year-old, nonprofit group that conducts an annual census of the Eastern and Western Monarch butterfly population, the number of Eastern Monarchs is down 90 percent from 20 years ago—from 1 billion to less than 100 million. The cause? A variety of factors, including habitat loss and extreme weather.
However, the increased use of herbicides, most notably Roundup, is largely to blame, according to the Xerces Society. The aggressive use of this weed killer has decimated the population of native milkweed, the sole food source of the monarch caterpillar.
I feel compelled to help. By sowing plants hospitable to monarchs laying their eggs, and that serve as a food source for monarch caterpillars on their evolutionary journey and as a nectar supply for adult monarch butterflies, we can make a difference.
I transformed a wildflower garden to one friendly to monarchs. I planted flower varieties that produce clusters of brightly colored, sweet-smelling flowers, including asters, daisies, butterfly bush, butterfly weed, lantana, marigolds, purple coneflowers and zinnias, golden rod, lilac and a variety of milkweed types. They are beautiful to look at, and fulfill a purpose.
The resulting impact—on my local monarch butterfly population and on me—was dramatic. The first visual evidence I witnessed, underscoring the value of my efforts, was the emergence of monarch caterpillars (larvae)—I checked the Internet to make sure that’s what they were—populating the branches of the milkweed.
Some days I counted as many as 13 caterpillars! Other days, there were fewer, prompting me to check their progress daily. In fact, most days started and ended with a trip to the garden to count the caterpillars or simply watch with wonder as they munched hungrily on milkweed plant leaves.
The good news
On days when more caterpillars appeared, I rejoiced. ‘It’s working,’ I thought to myself. On days when I counted fewer caterpillars, like an anxious mother I fretted: where are they? Did they simply wander away or were they eaten?
Mantis, ants, wasps, spiders, assassin or stink bugs, birds, lizards, mice and toads are just some of the creatures that prey upon monarch butterfly caterpillars. Happily, milkweed plants, on which the caterpillars feed, contain the toxic chemical cardenolides. Once caterpillars eat milkweed leaves, the chemical passes into their bodies. To avoid the ingested toxins, however, some predators have learned to gut the toxins from caterpillars by taking out their intestines before consuming the entire caterpillar body!
The monarch butterfly larva also is protected against predators through the development of a poisonous chemical called glycoside, which makes larvae distasteful and poisonous to predators. When the larvae grow into adults, the chemical passes into the adult monarch’s body. However, the toxins are prevalent at highest levels only in the abdomen and wings. Predators have learned to eat the palatable parts of the monarch and leave behind the poisonous parts!
Along the way
One day I noted with interest the appearance, seemingly overnight, of small yellow round particles prevalent on milkweed plant stems. Were these, I wondered, the elusive monarch butterfly eggs I had tried so diligently but unsuccessfully to locate on milkweed plants?
After consulting the Internet, I was disappointed to learn the yellow particles were actually a relentless attack of oleander aphids. While they are harmless to monarch caterpillars, the aphids suck the life from milkweed. The degree to which their infestations affect plant health is debatable, but if nothing else, they are unsightly. You can get rid of aphids by applying a soapy mixture of dish detergent and water or even rubbing alcohol.
What is my role?
I read up on the life cycle of the monarch butterfly, and reacquainted myself with the four stages we all learn about in school: egg, larvae (caterpillar), pupa (chrysalis) and adult butterfly. In just 25 to 32 days, Monarch metamorphosis (all four life-stages) is completed. I had seen larvae and adult butterflies, but as earnestly as I looked, I couldn’t find eggs or pupa.
The Monarch’s pupa or chrysalis is jade-green with a crown of gold. After the Monarch larva pupates into a beautiful chrysalis it takes six to seven days to hatch into an adult Monarch butterfly.
I learned you can aid the process by placing large branches around the garden on which the pupa can be housed and tethered, until the adult butterfly safely emerges. I never saw any pupa, even when I looked farther afield on a nearby shed, boulder, potted plant, climbing vine, fence, garden plants, patio furniture, window screen, and house siding—just a few of the many places they can be found. It’s not surprising, when you consider that only about 5 percent survive.
The more I learned, the more I wanted to help! Monarch caterpillars are voracious eaters and soon had eaten up most of the leaves on the existing milkweed plants! Experts advise planting milkweed in groups of six to provide adequate food sources. I planted more milkweed: the white, pink and mauve swamp milkweed; the orange and red butterfly milkweed; greenish white with purple tinged whorled milkweed; and more.
Ultimately, the experience was very fulfilling. Beyond watching the caterpillars, the most compelling aspect was observing with the pride of a parent the newly-born adult butterflies darting around our yard, seemingly happy, as they landed on the many butterfly-friendly flowers we grow.
It felt good to have helped the environment in this way, and I felt a kinship to both the monarchs and other gardeners who have taken monarch butterfly-raising into their souls.
You can help
If your school or nonprofit would like to create a butterfly-friendly garden to nourish a potential Monarch population, Baker Creek Heirloom Seeds, a purveyor of pure heirloom seeds, will help by sending you free milkweed seed! Contact them at firstname.lastname@example.org.