The monarch butterfly is probably the most popular and best recognized butterfly in North America. It is bright orange and black with white spots on the head and wing margins. Our meadows and shaded trails are full of monarchs these days, and I often see them feeding on the blue sage wildflowers.
The butterflies are migrating south and laying their eggs on milkweed plants, the host plant for the caterpillar. The caterpillar is identified by its yellow, white and black bands and the paired black filaments on the head and tail. While feeding on milkweed, the caterpillar ingests toxins (cardiac glycosides) that make it and the butterfly distasteful to predators such as birds. Monarchs have evolved a way to neutralize the toxins that would kill other insects.
The butterflies are heading to their wintering grounds in the mountainous forests of Central Mexico. Butterflies that are migrating now are not the ones we saw in the spring. They are fourth-generation butterflies.
Back in the spring, the butterflies that left their wintering grounds in Mexico travelled thousands of miles throughout North America to as far as Canada. As they moved north, the first-generation butterflies laid eggs on milkweed plants. After hatching and becoming butterflies, the second generation continued north, repeating the process to produce third and fourth-generation butterflies. The fourth-generation butterflies are the ones we now see migrating south.
The number of monarch butterflies has dramatically decreased in recent years. More than 90% of the monarchs in North America have disappeared in the last 20 years. Causes are loss of habitat and the use of herbicides, which kill milkweeds, the caterpillar’s only source of food.
To save the monarch from extinction, ranchers and farmers need to understand the threat of using herbicides on their properties. County governments should eliminate roadside spraying with herbicides.
I contacted our Tulsa County Commissioner and asked if the roadside spraying in our area could be stopped and explained why. He agreed, and we no longer have spraying along our mile of Lewis Avenue. Others should request the same. Additionally, homeowners could plant more milkweeds in their gardens.
