Tuesday, October 9, 2018

Monarch Rising

Dyana checks milkweed leaf for eggs
A few weeks ago, I visited with Dyana, a good friend in Burlington who had started to raise monarch butterflies—now preparing for their major migration back to Mexico. Dyana searches the milkweed growing in scrub patches in her neighbourhood and when she finds a leaf bearing a monarch egg, she brings it inside to protect the egg from parasites and other neighbourhood threats.

COSEWIC (the committee on the status of endangered wildlife in Canada) reported that the monarch is now officially “endangered”, victim to habitat loss of wintering grounds (through illegal logging) in Mexico, and increasing destruction of milkweed caterpillar breeding habitat by drought and insecticide in Canada and the United States. 

While GMO corn, canola and soybeans have been engineered to be immune to the herbicide Round-Up (glyphosate), which is used liberally in large corporate farms, milkweed—on which the monarch caterpillar exclusively feeds—and other native “weeds” are destroyed. In addition to its threat from liberal use of herbicides, the milkweed was additionally targeted as a noxious weed. It was only after serious lobbying by scientists and activists that the Ministry of Agriculture, Food and Rural Affairs removed milkweed from its list of noxious weeds so provincial inspectors would no longer target the plant for destruction.

Milkweed planted in a house owner's garden 
Close to a 90% reduction in monarchs was observed in the last two decades since Round-Up was aggressively introduced. The monarch butterfly migration is now recognized as a “threatened process” by the International Union for Conservation of Nature. “Deforestation, climate change, and increased use of herbicides targeting milkweed on farms caused the monarch’s North American population to decline precipitously, from nearly 1 billion in the mid-’90s to less than 35 million in 2013,” writes TVO.

Our role in Canada is paramount as part of the monarch’s four generation cycle. Overwintering butterflies leave Mexico in early spring and migrate into the southern US, where they lay their eggs on milkweed plants before dying. Just as in a relay race, the second generation feed only on milkweed, then as adults migrate further north in May/June into Canada to create the third generation of summer butterflies. The last generation returns in September/October to Mexico to overwinter. Unlike the previous three generations, the fourth generation monarch lives beyond two to six weeks in the warmer climate of California and Mexico until it is time to start the migration again in the spring.

Monarch butterfly egg with 1st instar head showing
Within about four days, the egg hatches into a monarch caterpillar, covered in white, black, and yellow stripes. When it emerges, it is very small; just like the egg itself, which Dyana admitted she missed seeing on many occasions until she’d trained her eye to see them. Eggs are only about the size of a pinhead or pencil tip. They are off-white or yellow, characterized by longitudinal ridges that run from the tip to the base. 

Monarch females usually lay a single egg on a milkweed plant, often on the bottom of a leaf near the top of the plant. They lay from 300 to 500 eggs over two to five weeks. The dark head of the developing caterpillar can be seen near the top of the egg prior to emergence. 
  
Monarch caterpillar-photo by Digital Still
Within 10 days the tiny and voraciously feeding caterpillar is full size and a robust 25-45 mm long and 5-8 mm wide. When the caterpillar develops “spats” on its copious legs, it is ready to find a place to hang upside down and become a chrysalis. Within another 10 days the butterfly emerges, fully formed and ready to return outside. Because the monarch is not able yet to take flight, its first few hours out of the chrysalis are perilous. Another butterfly helper, 
Margaret McRae shares that: “One time, I had two butterflies emerge within 15 minutes of each other. I was outside with them when a wasp attacked one and started eating it. A neighbour kid came by and we stood there for two hours, watching over the other butterfly to protect it from the wasps.”
Caterpillar hangs and forms a chrysalis
In 2014, the David Suzuki Foundation launched their “Got Milkweed?” campaign. First they convinced a nursery to grow the plant (which was considered a weed and not sold at garden centres), then they encouraged members of the public to plant it around their homes. “We put 500 plants on order hoping we could unload them, or my backyard would be full of milkweed,” Roberts says. “We sold those in about two days. I think we sold 4,000 that first year.”
Chrysalis attached to a surface Dyana provided
Roberts says the “Got Milkweed?” campaign has done well every year since and has expanded west to Manitoba and east to the Maritimes. He hopes that success will carry over to the Butterflyway Project. “Part of the work now is to take some of the energy and enthusiasm that people have for monarchs and put it into places that benefit other species,” he says. “My ambition is to have people identify at least a couple butterflies that float through their backyards.”
Chrysalis "shell" left behind once butterfly emerged
Dyana took me on a tour of her neighbourhood and I was delighted to see several gardens with planted milkweed for the monarch butterfly.

Things that you can do to help:

·      Plant a butterfly garden. Add plants that take the monarch from tiny egg to caterpillar to chrysalis to adult. These include plants in the milkweed family and nectar-rich blooming plants. Most nurseries sell pollinator mix seeds.

·      Plant milkweeds in your garden. Monarchs lay their eggs on milkweed plants. The adults get most of their energy from the nectar of plants.

·     
Front garden with planted milkweed
Place your garden where it receives lots of sunlight but is also protected from the elements. You can create a shelter using trees, shrubs and perennials as well as logs and stones. Flat stones can serve as hot spots for butterflies to get warm.

·      Write your MLA / MNA / MPP and the minister responsible for environmental issues. Let them know you are concerned. Letters are important and taken very seriously by government; they understand that for every letter sent there are many who think similarly but aren’t writing.