By Rebecca Bracken
While I suspect the majority of people here in Texas have seen a monarch butterfly, most probably don’t know that they make one of the most amazing migrations on the planet. Monarchs, known for their iconic shades of orange and black, are one of the most recognized butterfly species in the United States. But there is much more to this tiny pollinator than just their beauty.
Monarch butterflies have a typical insect lifecycle. They begin their lifecycles as eggs, which are laid on milkweed plants and hatch in a quick two to five days. The emerging caterpillars go through five stages called instars in only two weeks, before transitioning into a brilliant green and gold chrysalis. Finally, in another two weeks, a new butterfly will break free from the chrysalis and spread its wings for the first time. Eventually the cycle repeats itself, with new eggs laid on fresh milkweed.
But there is something truly unique and wonderful about a portion of this cycle. Often called one of nature’s greatest phenomena, monarchs go into a state of suspended reproduction each fall, called diapause. During this time, they begin migrating to their overwintering sites, which are sometimes up to 3,000 miles away. This trip can last over two months! The monarchs will then spend the winter in Mexico, in large groups commonly called kaleidoscopes or swarms. If you ever have a chance to visit one of these sites, I’m told it is quite amazing. Entire trees can be completely covered by butterflies!
In early spring, the monarchs mate at their overwintering sites before dispersing and heading back north. The same individuals that completed the treacherous fall migration will fly back to the breeding groups. While there, the monarchs lay eggs, and several generations of offspring occur throughout the spring and summer months. As fall hits again, a new generation of butterflies will begin fall migration for the very first time.
Monarchs, like many organisms, are declining across much of their breeding range. Their numbers have dropped so much that the U.S. Fish and Wildlife Service proposed listing the species as threatened under the Endangered Species Act. Monarch butterflies are currently listed as endangered in Canada, and are legally protected at a UNESCO World Heritage Site in Mexico called the Monarch Butterfly Biosphere Reserve. The monarchs are dependent on milkweed as it is the only plant they will lay their eggs on, and is the only source of food for the emergent caterpillars. As agricultural and urban development increase in the U.S., the amount of milkweed on the landscape has decreased significantly.
We are often asked what our community can do to help birds, but there are some very simple actions you can take to help monarchs and other butterflies. We always encourage planting native plants including native milkweeds and other flowering plants. There are a number of native milkweeds depending on where you live, and they are often very easy to take care of. Other plants such as asters, goldenrods, and blue mistflower have long blooming seasons that support monarchs throughout the year. Conservationists also recommend avoiding herbicides and insecticides as they harm monarchs and other pollinators; look for organic, chemical-free gardening choices. Encourage others to create greenspaces in parks, roadside, and schoolyards!
If you are curious about monarch migration, check out Project Monarch, Monarch Watch, and Journey North. Each is a citizen science-based research program that monitors monarch populations. Project Monarch is one of the newest programs that enables the public to collect monarch migration information. Tiny tracking devices that function like an airtag are glued to a monarch, which can then be tracked using Bluetooth technology. This means your phone can detect tagged monarchs! All you have to do is head outside, look for monarchs, and use a free app to record and upload detections. What could be easier?
Photo: An adult Monarch Butterfly
Credit: Thomas Bresson, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons
