by Guest Contributor Leslie Cooper, Arkansas Monarch and Pollinator Coordinator
The monarch butterfly (Danaus plexippus) is one of the most iconic insects. Their fantastic migration stretches nearly 3,000 miles from their overwintering grounds in central Mexico, across the United States, and into the southern part of Canada. Because of their distinguishing orange and black wings, they are easily recognizable. Sadly, over the past two decades their populations have been in decline, much like many of our grassland songbirds, pollinators, and other wildlife. Fortunately, in recent years there has been a resurgence in pollinator conservation. Though monarchs are not as strong of pollinators as bees, their notoriety brings attention to the issue. This is an unprecedented time for pollinator conservation, as there is growing support for native habitat restoration and recognition of the importance of our native pollinators.
There are three distinct populations of monarchs in the United States. The smallest is a non-migratory population in southern Florida that breeds year-round. The second is the western population that is west of the Rocky Mountains. These butterflies overwinter along the coast of California, and their population has plummeted in the last three years. According to the Xerces Society, the western monarch population is less than 0.01% of historic populations, and the migration is now in peril. The Xerces Society also reported that, “Fewer than 2,000 monarchs were counted in California’s overwintering sites during the 2020-2021 population survey.”
The monarchs that we observe here in Arkansas are considered part of the eastern migratory population. This population is found east of the Rockies and overwinters in the oyamel fir (Abies religiosa) forests of central Mexico. Shockingly, these overwintering sanctuaries were not discovered until 1975, after Dr. Fred Urquhart had spent nearly 40 years searching for where the butterflies went in the winter. Through the first monarch tagging program and a network of volunteers, these remarkable places were discovered.
While the eastern population is not as imperiled as their western counterpart, their population also reached a record low during the 2013–2014 overwintering season. The eastern population is monitored by the total area occupied (in hectares) by monarch colonies at the overwintering sites in Mexico. The record low was less than one hectare occupied by monarchs (one hectare is equivalent to about 2.5 acres). This prompted a Presidential Memorandum to be issued in June 2014, which directed federal actions to address pollinator conservation.
Arkansas Monarch Conservation Partnership
In the past it was recommended that we follow, “the Rule of 3,” meaning that we include a minimum of three species that bloom in each the spring, summer, and fall (i.e. a total of nine blooming species). However, some people misunderstand this to mean that they only need to pick nine native species for their pollinator plantings instead of treating that rule as the minimum guideline. It is far more beneficial to maximize the number of native species planted so that we provide a diversity of flower shapes, sizes, and colors to benefit an array of pollinator and insect species. Some pollinators are considered generalists, like European honey bees, bumble bees, and monarch butterflies, where they forage on a variety of blooming species. Others, like our native squash bees, are specialist pollinators that only forage on a specific genus or species. We can benefit generalist and specialist pollinators by planting a variety of native plants.
When selecting native species, it is particularly important to include early- and late-blooming species. We see the greatest number of monarchs in Arkansas during the spring and fall migration, so it is important to provide these nectar resources during these times to literally “fuel” the monarch migration. Some of our native bee species also depend on early-blooming plants for nectar and pollen.
It is also important to decrease or eliminate the use of pesticides in your garden or yard. Herbicides are an essential tool to control non-native and invasive species. The controlled application of the correct chemical at the right time allows land managers to effectively battle these invasive species so they can establish, enhance, and manage native pollinator habitat. In a pollinator garden, insecticides should not be used, even if they are considered organic. Insecticides do not discriminate against killing the beneficial insects that are also in your garden. It is also important to be mindful of what plants you purchase and if they have been treated with a systemic insecticide. Systemic insecticides are water-soluble and are taken up by the plant, making the plant tissue toxic to insects that may consume it. Neonicotinoid insecticides (or neonics) are particularly harmful to pollinators.
If you are a landowner interested in establishing monarch and pollinator habitat on your property, you may be eligible for federal and state cost-share programs and can receive free technical assistance from a Natural Resources Conservation Service (NRCS) Field Office. You can email me at [email protected] and I’d be happy to connect you to your local resources. If you are interested in creating a pollinator garden, there are resources on our website , including a recommended native plant list and maintenance guide.
Monarchs are host plant specialists, which means that female monarchs only lay their eggs on milkweed species and monarch caterpillars only consume milkweed. When planning your native monarch and pollinator habitat, make sure to include at least two native species of milkweed. Milkweeds are essential to the monarch life cycle.
There are 21 species of milkweed that are native to Arkansas. In my own garden habitat, I have eight species that I have managed to propagate from seed or purchased at native plant sales over the last two years. I have observed monarch caterpillars on all eight species.
It is recommended to stick with planting milkweed that is native to your area of Arkansas. Our native milkweeds are perennials that die back every winter and are wonderful sources of pollen and nectar. Tropical milkweed (Asclepias curassavica) should not be planted in Arkansas, as it poses several risks to monarchs. Tropical milkweed is also called bloodflower, Mexican butterfly weed, scarlet milkweed, and cotton bush. Tropical milkweed is attractive to many gardeners or monarch-enthusiasts because it is easy to propagate and readily commercially available. However, tropical milkweed can be more harmful to monarchs than helpful. Often it is planted as an annual species, but it can overwinter during mild winters and facilitate the transmission of the protozoan parasite Ophryocystis elektroscirrha (OE) and infect monarchs with spores left on the plant. Monarchs that are heavily infected with OE cannot successfully eclose, or emerge, from their chrysalises. Unlike native milkweed, tropical milkweed also has the potential to become toxic to monarchs due to increased cardenolide concentrations under warmer conditions associated with climate change (Faldyn et al. 2018). Although cardenolides are the compounds naturally occurring in milkweeds that monarchs are adapted to eating, they can become toxic if above a certain threshold. The presence of tropical milkweed can also cue migrating monarchs that are in a state of reproductive diapause to begin reproducing (Majewska and Altizer 2019). Reproductive diapause is what allows the migrating generation of monarchs to live up to nine months and overwinter so that the migration can persist. Monarchs that exit reproductive diapause cannot overwinter and therefore decrease the overwintering pool. To read more on tropical milkweed, visit: https://xerces.org/blog/tropical-milkweed-a-no-grow.
You can directly benefit monarchs by incorporating native plants into the landscapes that surround you to create the essential habitat they depend on. Dr. Doug Tallamy said in his latest book, “Nature’s Best Hope,”: “If half of American lawns were replaced with native plants we would create the equivalent of a 20 million-acre national park – nine times bigger than Yellowstone, or 100 times bigger than Shenandoah National Park.” If everyone helped create native habitat, think of the impact we could have for monarchs and our other pollinators.
You can volunteer for native seed collections that are hosted by the ANHC, Audubon Arkansas, and other conservation organizations. You can also join the Arkansas Monarch Mapping Project on iNaturalist and add your monarch observations to help us better understand how monarchs migrate across Arkansas and inform management decisions. Visit our website to learn more about community science opportunities and get habitat resources: https://www.arkansasmonarchs.org/.
References
Photos:
Photo 1 — Monarch butterfly (Danaus plexippus) flying over rattlesnake master (Eryngium yuccifolium) at Railroad Prairie Natural Area. Photo by Leslie Cooper.
Photo 2 — Monarch butterfly (Danaus plexippus) nectaring on western ironweed (Vernonia bladwinii). Photo by Leslie Cooper.
Photo 3 — White milkweed (Asclepias variegata). Photo by David Arbour.
Photo 4 — Monarch butterfly (Danaus plexippus) chrysalis on a bluebird box. Photo by Leslie Cooper.
Photo 5 — Monarch butterfly (Danaus plexippus) nectaring on prairie gayfeather (Liatris pycnostachya) at H.E. Flanagan Prairie Natural Area. Photo by Leslie Cooper.
The monarch butterfly (Danaus plexippus) is one of the most iconic insects. Their fantastic migration stretches nearly 3,000 miles from their overwintering grounds in central Mexico, across the United States, and into the southern part of Canada. Because of their distinguishing orange and black wings, they are easily recognizable. Sadly, over the past two decades their populations have been in decline, much like many of our grassland songbirds, pollinators, and other wildlife. Fortunately, in recent years there has been a resurgence in pollinator conservation. Though monarchs are not as strong of pollinators as bees, their notoriety brings attention to the issue. This is an unprecedented time for pollinator conservation, as there is growing support for native habitat restoration and recognition of the importance of our native pollinators.
Monarch Populations
There are three distinct populations of monarchs in the United States. The smallest is a non-migratory population in southern Florida that breeds year-round. The second is the western population that is west of the Rocky Mountains. These butterflies overwinter along the coast of California, and their population has plummeted in the last three years. According to the Xerces Society, the western monarch population is less than 0.01% of historic populations, and the migration is now in peril. The Xerces Society also reported that, “Fewer than 2,000 monarchs were counted in California’s overwintering sites during the 2020-2021 population survey.” The monarchs that we observe here in Arkansas are considered part of the eastern migratory population. This population is found east of the Rockies and overwinters in the oyamel fir (Abies religiosa) forests of central Mexico. Shockingly, these overwintering sanctuaries were not discovered until 1975, after Dr. Fred Urquhart had spent nearly 40 years searching for where the butterflies went in the winter. Through the first monarch tagging program and a network of volunteers, these remarkable places were discovered.
While the eastern population is not as imperiled as their western counterpart, their population also reached a record low during the 2013–2014 overwintering season. The eastern population is monitored by the total area occupied (in hectares) by monarch colonies at the overwintering sites in Mexico. The record low was less than one hectare occupied by monarchs (one hectare is equivalent to about 2.5 acres). This prompted a Presidential Memorandum to be issued in June 2014, which directed federal actions to address pollinator conservation.
Listing under the Endangered Species Act
The decline also led several national groups to petition the U.S. Fish and Wildlife Service (USFWS) to list the monarch under the Endangered Species Act (ESA). In December 2020, after an extensive status assessment of the monarch butterfly, it was determined that listing the monarch was “warranted but precluded at this time by higher priority listing actions,” according to the statement released by the USFWS. This designation means that the monarch is considered a candidate for listing and their status will be reviewed annually until a listing decision is made. Often people are confused by this listing determination when they learn about the status of the western monarch population. The ESA allows distinct population segments of vertebrate species to be listed, but since the monarch is an invertebrate, the western population cannot be listed by itself. You can read more about the listing decision at this website.Arkansas Monarch Conservation Partnership
In 2015, partners across Arkansas, including the ANHC, recognized the importance of pollinator conservation and the urgent need to take action. Following the first Arkansas Monarch Summit in November 2015, the Arkansas Monarch Conservation Partnership was formed. The steering committee finalized the Arkansas Monarch and Pollinator Conservation Plan (the Plan) in May 2018. This statewide strategic plan focuses on three main categories of targeted action: 1) monarch and pollinator habitat conservation, enhancement, and restoration; 2) research and monitoring; and 3) outreach and education. Though the monarch is the primary focus of the Plan, the steering committee determined that the plight of all pollinators should be included in the conservation goals, particularly the unique habitat needs of our native bee species.
Creating Monarch and Pollinator Habitat
The most important thing that Arkansans can do to help monarchs and native bee species is to create habitat by planting Arkansas native plants. These plants occur naturally in a particular region, ecosystem, or habitat without direct or indirect human intervention, and you can help restore their availability. Whether planning to manage large acreages for pollinators, planting a small pollinator garden or “pocket prairie,” the key is maximizing the diversity of native wildflower species to provide a succession of blooms. This is important so that pollinators have a consistent supply of nectar and pollen throughout the growing season. Creating or enhancing native habitat is the key to monarch and pollinator conservation.In the past it was recommended that we follow, “the Rule of 3,” meaning that we include a minimum of three species that bloom in each the spring, summer, and fall (i.e. a total of nine blooming species). However, some people misunderstand this to mean that they only need to pick nine native species for their pollinator plantings instead of treating that rule as the minimum guideline. It is far more beneficial to maximize the number of native species planted so that we provide a diversity of flower shapes, sizes, and colors to benefit an array of pollinator and insect species. Some pollinators are considered generalists, like European honey bees, bumble bees, and monarch butterflies, where they forage on a variety of blooming species. Others, like our native squash bees, are specialist pollinators that only forage on a specific genus or species. We can benefit generalist and specialist pollinators by planting a variety of native plants.
When selecting native species, it is particularly important to include early- and late-blooming species. We see the greatest number of monarchs in Arkansas during the spring and fall migration, so it is important to provide these nectar resources during these times to literally “fuel” the monarch migration. Some of our native bee species also depend on early-blooming plants for nectar and pollen.
It is also important to decrease or eliminate the use of pesticides in your garden or yard. Herbicides are an essential tool to control non-native and invasive species. The controlled application of the correct chemical at the right time allows land managers to effectively battle these invasive species so they can establish, enhance, and manage native pollinator habitat. In a pollinator garden, insecticides should not be used, even if they are considered organic. Insecticides do not discriminate against killing the beneficial insects that are also in your garden. It is also important to be mindful of what plants you purchase and if they have been treated with a systemic insecticide. Systemic insecticides are water-soluble and are taken up by the plant, making the plant tissue toxic to insects that may consume it. Neonicotinoid insecticides (or neonics) are particularly harmful to pollinators.
If you are a landowner interested in establishing monarch and pollinator habitat on your property, you may be eligible for federal and state cost-share programs and can receive free technical assistance from a Natural Resources Conservation Service (NRCS) Field Office. You can email me at [email protected] and I’d be happy to connect you to your local resources. If you are interested in creating a pollinator garden, there are resources on our website , including a recommended native plant list and maintenance guide.
Milkweed
Monarchs are host plant specialists, which means that female monarchs only lay their eggs on milkweed species and monarch caterpillars only consume milkweed. When planning your native monarch and pollinator habitat, make sure to include at least two native species of milkweed. Milkweeds are essential to the monarch life cycle. There are 21 species of milkweed that are native to Arkansas. In my own garden habitat, I have eight species that I have managed to propagate from seed or purchased at native plant sales over the last two years. I have observed monarch caterpillars on all eight species.
It is recommended to stick with planting milkweed that is native to your area of Arkansas. Our native milkweeds are perennials that die back every winter and are wonderful sources of pollen and nectar. Tropical milkweed (Asclepias curassavica) should not be planted in Arkansas, as it poses several risks to monarchs. Tropical milkweed is also called bloodflower, Mexican butterfly weed, scarlet milkweed, and cotton bush. Tropical milkweed is attractive to many gardeners or monarch-enthusiasts because it is easy to propagate and readily commercially available. However, tropical milkweed can be more harmful to monarchs than helpful. Often it is planted as an annual species, but it can overwinter during mild winters and facilitate the transmission of the protozoan parasite Ophryocystis elektroscirrha (OE) and infect monarchs with spores left on the plant. Monarchs that are heavily infected with OE cannot successfully eclose, or emerge, from their chrysalises. Unlike native milkweed, tropical milkweed also has the potential to become toxic to monarchs due to increased cardenolide concentrations under warmer conditions associated with climate change (Faldyn et al. 2018). Although cardenolides are the compounds naturally occurring in milkweeds that monarchs are adapted to eating, they can become toxic if above a certain threshold. The presence of tropical milkweed can also cue migrating monarchs that are in a state of reproductive diapause to begin reproducing (Majewska and Altizer 2019). Reproductive diapause is what allows the migrating generation of monarchs to live up to nine months and overwinter so that the migration can persist. Monarchs that exit reproductive diapause cannot overwinter and therefore decrease the overwintering pool. To read more on tropical milkweed, visit: https://xerces.org/blog/tropical-milkweed-a-no-grow. Monarch Rearing
The best thing that people can do to benefit monarchs is to create habitat for them by planting native wildflowers and milkweed. With proper guidance and training from experts, rearing small numbers of monarch butterflies can be beneficial for educational and community science purposes. However, scientists and conservationists have noted serious concerns for rearing at a large scale or purchasing commercially available monarchs. Rearing monarchs can lead to the spread of disease that could affect the wild population, could affect migratory ability and general fitness, and is not an effective conservation solution to the declining monarch population. The key to monarch conservation is creating, enhancing, and restoring native plant communities to support a robust wild monarch population to ensure the migration continues. To learn more about problems and concerns with captive rearing, visit: https://xerces.org/blog/keep-monarchs-wild, or https://moformonarchs.org/hand-rearing-monarchs/.How You Can Help
You can directly benefit monarchs by incorporating native plants into the landscapes that surround you to create the essential habitat they depend on. Dr. Doug Tallamy said in his latest book, “Nature’s Best Hope,”: “If half of American lawns were replaced with native plants we would create the equivalent of a 20 million-acre national park – nine times bigger than Yellowstone, or 100 times bigger than Shenandoah National Park.” If everyone helped create native habitat, think of the impact we could have for monarchs and our other pollinators.You can volunteer for native seed collections that are hosted by the ANHC, Audubon Arkansas, and other conservation organizations. You can also join the Arkansas Monarch Mapping Project on iNaturalist and add your monarch observations to help us better understand how monarchs migrate across Arkansas and inform management decisions. Visit our website to learn more about community science opportunities and get habitat resources: https://www.arkansasmonarchs.org/.
References
Photos:
Photo 1 — Monarch butterfly (Danaus plexippus) flying over rattlesnake master (Eryngium yuccifolium) at Railroad Prairie Natural Area. Photo by Leslie Cooper.
Photo 2 — Monarch butterfly (Danaus plexippus) nectaring on western ironweed (Vernonia bladwinii). Photo by Leslie Cooper.
Photo 3 — White milkweed (Asclepias variegata). Photo by David Arbour.
Photo 4 — Monarch butterfly (Danaus plexippus) chrysalis on a bluebird box. Photo by Leslie Cooper.
Photo 5 — Monarch butterfly (Danaus plexippus) nectaring on prairie gayfeather (Liatris pycnostachya) at H.E. Flanagan Prairie Natural Area. Photo by Leslie Cooper.