How Long Do Monarch Butterflies Live?

How Long Do Monarch Butterflies Live?

According to Rebeca Quiñonez-Piñón, the National Wildlife Federation’s (NWF) monarch recovery strategist, monarch butterflies generally only live 28 to 32 days, but the generation that migrates is different. Sometimes dubbed the “super,” or “Matusalem,” generation, these monarchs live from 6 to 9 months and will live throughout the entire migration, during winter, and on the first leg of the migration north the following spring. They won’t die until after they fly north in March and lay eggs on the first milkweed they find, most likely somewhere in Texas.

In contrast, the subsequent generations that migrate back north during spring and summer will live typically brief lives, mating and dying as their offspring continue the journey. It’ll take about three generations for the monarchs to return to their summer breeding grounds.

Monarch butterfly type of migration

How such a tiny insect can fly such a long distance and how its life span can be vastly longer than its immediate progenitors is one of the fascinations of science.

“That’s the miracle of the monarchs!” says Mary Phillips, head of the NWF’s Garden for Wildlife and Certified Wildlife Habitat programs. The miracle, she says, is that the monarchs’ migratory behavior somehow seems to be passed down through their genes, and it guides these little insects on their spectacular fall journey. “This is the only insect known to have a two-way migration,” says Quiñonez-Piñón. “The same individuals that migrate in the fall overwinter for 4 to 5 months and then migrate back north in the spring.”

When Do Monarch Butterflies Migrate North?

The fall migration for both the eastern and western populations is critical to scientists, because that’s when they count or estimate the numbers in the overwintering grounds to gauge the success of the migration and the health of the species. In Mexico, scientists arrive at those numbers by estimating the numbers of butterflies per hectare of forest.

In the 1990s, the eastern population of monarch butterflies numbered almost 700 million, while their population today has been drastically reduced by about 80 percent. This year’s annual survey of the eastern monarch population by the World Wildlife Fund in Mexico indicates that the monarch’s long-term downward trajectory is continuing. During the winter of 2022-23, the butterflies occupied an estimated 2.21 hectares of forest, a decline of approximately 22 percent compared with the previous winter, when monarchs occupied 2.84 hectares.

Are monarch butterflies endangered?

The monarch butterfly was put on the International Union for Conservation of Nature (IUCN) endangered species list in 2022. The U.S. Fish and Wildlife Service has placed monarchs as a candidate for consideration on the official U.S. endangered species list, with a final decision coming during the 2024 fiscal year. “The current 5-year population average from 2018 to 2022 is less than 50 percent of the 6-hectare recovery goal laid out in the Mid-America Monarch Conservation Strategy,” adds Quiñonez-Piñón.

The monarch butterfly population is in decline because of a number of factors. A major one is the loss of milkweed and nectar-producing plants in the central U.S., as well as the degradation of native habitat stopover areas in the south-central states. Monarch butterflies are also impacted by insecticides and the climate crisis, which Phillips says may also affect migration flight patterns.

The monarch’s peril isn’t limited to the iconic insect. “The monarch butterfly is a sentinel species, whose health and condition mirrors many other wildlife populations, especially pollinators,” explains Quiñonez-Piñón. “These continuing low population numbers are a warning sign that cannot be overstated.”

What Do Monarchs Butterflies Eat?

These declining population numbers are also a call to action. That’s where home gardeners come in. Fall gardens are as critical to stopping the decline of monarchs as spring and summer gardens.

“The generation flying south to Mexico is going to need a ton of nectar,” says Phillips. “That’s why home gardeners need to plant asters, goldenrods, liatris, echinacea, Coreopsis, Rudbeckia, and other flowers that bloom late summer and into the fall to provide nectar to fuel this phase of the journey.” Consider planting milkweed and nectar-producing flowers that are native to your area to give the plants the greatest chance to thrive and to benefit monarchs.

Milkweed not only provides nectar to adult monarchs, but it’s also the only plant monarch caterpillars can eat, since the plant and butterfly species have co-evolved together.

The toxic cardenolides in milkweed generally protect the caterpillars from predators, though the monarch eggs and caterpillars are vulnerable to predators, such as the praying mantis, parasitic flies, and wasps. Some predators have developed a tolerance or learned to minimize their exposure when eating the adult butterflies. “Black-backed orioles avoid the toxin-rich cuticle of the monarchs’ abdomen by cutting them open before eating them. Black-headed grosbeaks can eat large quantities of monarchs without getting poisoned,” says Quiñonez-Piñón. “Grosbeaks, somehow, can tolerate higher levels of cardenolides and eat the monarch’s whole abdomen.”

Two native milkweeds popular with home gardeners that can be planted in many areas are the pink-flowering swamp milkweed (Asclepias incarnata) and butterfly weed (Asclepias tuberosa), which has brilliant orange flowers.

Avoid planting the non-native tropical milkweed (Asclepias curassavica). According to Quiñonez-Piñón, the presence of tropical milkweed can cause migrating monarchs to mate and then linger in place instead of continuing the journey. Furthermore, they may mate with their offspring, which can result in birth defects for the next generation.

There are two approaches to introducing milkweed plants to your garden. One is to grow the plants from seed. The other is to start with seedlings from plant nurseries. There’s not a right or wrong answer. You just have to ask yourself: “What’s right for me?” Here’s a guide to help answer that question.

Germinating Milkweed Seeds

Germinating milkweed seeds and raising the tender seedlings requires patience, time, and even a little luck. You’ll need to mimic the process of how milkweeds germinate in nature. Depending on where you live, you’ll have to create winter-like conditions, and this can be difficult if you’re trying to germinate seeds in a warm season. But it can be done if you’re up for the challenge.

“Germinating milkweed seeds isn’t like when you were back in elementary school and stuck a bean in a cup and came back a few weeks later and you had this tall plant,” says Shubber Ali, CEO of Garden for Wildlife, an online native plant business in which a portion of proceeds benefit the NWF’s national conservation habitat education program.

The first step is selecting seeds of milkweeds that are native to your region. Obtain seeds from a reputable source and as locally as possible to ensure good germination rates and healthy plants.

Germinating the seeds will be dependent on your location. The germination instructions vary based on location. Most milkweed seeds will need some form of cold stratification. Milkweed seeds can be directly sown in fall or early spring or placed in the refrigerator for at least 30 days to simulate winter; some species of milkweed will need longer. Some people put the seeds in wet sand or potting soil when they cold-stratify milkweed seeds in the refrigerator, while others wrap them in moist paper towels.

“That sort of works,” says Ali, who has tried the paper-towel method with mixed results. “But it’s not the same as the freezing and expanding that takes place outdoors that cracks the shell coat, which helps with germination. You’re trying to mimic that.”

Planting Milkweed Seedlings

Starting off with seedlings in small pots is an excellent approach for those who don’t have the time or inclination to grow milkweed from seed. Carefully tend to your seedlings for weeks, either indoors or outdoors depending on your location, and harden them off before planting in your garden.

Garden for Wildlife offers milkweed and other native plant collections for your regional area, based on your ZIP code. From there, you can filter for light conditions, soil moisture, plant height, wildlife benefits, and other characteristics. So far it’s contracted with native plant wholesalers in 38 states, with plans to scale up.

“We’re making a difference,” says Ali, “even for people in an apartment with one planter.” Ali wants people to put milkweed and other native plants in the ground. “Then I want them to tell somebody else to put a plant in the ground. And that will start to change people.”

Where Do Monarchs Butterflies Go When They Migrate?

Monarchs are a topic of conservation interest and cultural intrigue in their migratory path as they fly toward Mexico. Monarch enthusiasts anticipate their arrival at wildlife refuges where they stop to rest and refuel in natural places. These sites include the Neal Smith National Wildlife Refuge in Iowa; the Quivira National Wildlife Refuge in Kansas; the John Heinz National Wildlife Refuge in Pennsylvania; the Eastern Shore of Virginia National Wildlife Refuge; the St. Marks National Wildlife Refuge in Florida; and the Balcones Canyonlands National Wildlife Refuge in Texas.

Nowhere, though, is their arrival awaited with greater anticipation than in Mexico. To add to the mystique of the monarch, their fall migration concludes when they arrive in Mexico, coinciding with one of the most significant events in Mexican culture, Día de Muertos or Day of the Dead, from Nov. 1 to 2. According to Quiñonez-Piñón, many people in Mexico believe in the pre-Hispanic legend that the returning butterflies carry with them the souls of ancestors from the afterlife.

“The connection between our traditions, culture, and the monarch butterfly is a great opportunity to uplift our efforts to conserve and protect the butterfly,” writes Quiñonez-Piñón. “Now deeply rooted in our traditions, the monarch deserves that we take care of its habitats, that we advocate and speak for it, and that we ask others to help us conserve this amazing creature that has contributed to our lives in so many ways. The deep, emotional connection that many of us have with the monarch might be beyond words, and it makes us care for its survival as a species.”

Becky Griffin seconds Quiñonez-Piñón’s thoughts. Griffin, the coordinator for the Great Southeast Pollinator Census, was in the biosphere reserve in February with a group of scientists and photographers on a trip organized by Monarchs Across Georgia (www.EEAlliance.org/Monarchs-Across-Ga.html), a monarch conservation group. “There are no words to describe observing the butterflies in their overwintering grounds,” says Griffin. “I’ve tried magical, otherworldly, spiritual … ” Her voice trails off in a loss for further words.

While there, the group visited a school in the town of Angangueo and asked the children about loss of habitat in the overwintering forests. Finally, one sixth-grade girl, sounding frustrated, stood up and said, “We’re seeing less and less butterflies here every year. What are you people doing up there to save them?”

“That made the hair on the back of my neck stand up,” recalls Griffin. “It’s all we talked about on the trip home.”

How Do Western Monarch Butterflies Migrate?

The Western population of monarch butterflies journey south in fall about 300 miles, from as far as the southern region of the Canadian province of British Columbia, to overwinter near the Pacific Coast, ranging from Marin County to Baja California, Mexico. In the 1980s, the western population was more than a million, and now it has severely declined by 99%, according to The Xerces Society.

In The Xerces Society’s 2022 Western Monarch Thanksgiving Count, 335,479 butterflies were sighted, compared with 247,237 in 2021. However, the California groves, where overwintering monarchs cluster in 200 to 300 small colonies, suffered extensive tree loss from winter storms after the Thanksgiving count. The storms forced these monarchs to search for new shelter. No one knows yet what the consequences of those storms will be.

“It’s clear that extreme weather events, such as California’s latest winter extreme rainfalls, show the devastating impacts of the climate crisis on the butterfly,” says Quiñonez-Piñón. “Joint efforts to reverse the western monarch declines should be steady, long-term, and primarily focused on restoring and conserving their breeding and overwintering native habitats through effective climate-adaptation strategies. Climate change has its own agenda, and we must counteract it fiercely to protect the monarch and its incredible migration.”

How You Can Help Monarchs

Let’s all do what we can to preserve these magnificent creatures for future generations. The home gardener can help counteract this decline by planting native milkweed and nectar-rich plants for migrating monarchs. Together we can make sure that these incredible creatures continue their fascinating journey year after year.

Tom Oder is an independent journalist living in Atlanta, Georgia. He writes about gardening, the environment, and agribusiness.