Partnering to conserve the monarch butterfly migration

Frequently Asked Questions

The following are some frequently asked questions of the Monarch Joint Venture and from our Monarch Conservation Webinars. Read these over to find out the answers to your questions about everything monarchs. If your question isn't listed here, feel free to get in touch with us.

Threats

Does the decline in available milkweed coincide with greater use of genetically modified corn and soybeans?

Yes, research by Dr. John Pleasants and Dr. Karen Oberhauser indicate that the loss of agricultural milkweeds is a major contributor to the decline in the monarch population

Are invasive plants a threat to monarchs?

Invasive species do not typically pose a direct threat to monarchs, with the exception of two species of invasive swallow-wort, which can serve as a "sink". These species, black swallow-wort (Cynanchum louisea) and pale swallow-wort (Cynanchum rossicum) confuse egg-laying females; if a female monarch oviposits (lays eggs) on these species, mistaking them for milkweed, the caterpillars will not survive because the swallow-wort is not a viable food source for them. While not a widespread invasive across North America currently, it is important to understand and control these invasive species to minimize their risk for monarchs. Other invasive plants can also cause concern for monarchs. While some invasive species may provide an abundance of nectar for monarchs and other pollinators during certain times of the year, if left uncontrolled invasive species can be extremely detrimental to the long-term viability of a habitat. Invasive species may out-compete other natives and decrease the overall diversity at the site. This could reduce or eliminate milkweed that is present at a site, and could decrease the diversity of nectar resources that are available throughout the growing season. Control of non-native invasive species in a habitat is recommended to ensure monarch habitat exists for a long time! 

It will freeze soon in my area, and I'm still seeing monarch caterpillars. Will they survive? What should I do?

In order for an adult monarch to fly, temperatures need to be above 55 degrees Fahrenheit. While monarch eggs and caterpillars can survive some exposure to cold, these cooler temperatures slow their development time and prolonged exposure may cause sub-lethal effects (e.g. monarchs may take longer to develop, leaving them more vulnerable to disease and predation). 

Since there is not a distinct boundary separating breeding and migratory generations, there will be caterpillars that are developing late into the season as temperatures decrease and milkweed ages or senesces. Not all of them will survive. In many cases, the milkweed plants (and caterpillar food source) may be more vulnerable to freezing temperatures than the caterpillars themselves. Similarly, killing frosts can eliminate remaining nectar plant species that are in bloom, which feed fall migratory adult monarchs. These late season monarchs have a lower chance of surviving the long-distance migration due to a number of additional stressors that they face, including temperatures too cold for them to fly and lack of available nectar to fuel their journey.

If temperatures are predicted to stay around or above 55 F, you may consider bringing a few late caterpillars indoors to speed up their development in your warmer house before sending them off on their migratory journey (when at least 55 F, and ideally sunny). Please use best practices for rearing monarchs when bringing caterpillars indoors. Late season observations and rearing (survival) should also be reported to monarch citizen science programs

As milkweed and nectar resources become less available (and temperatures continue to drop), you may be able to bring caterpillars indoors to raise them to adulthood, but the likelihood of those monarchs reaching their overwintering destinations decreases drastically after peak migration. In these cases, you may wish to keep those adults for use in educational programming, or provide them to a local school, educational facility, or youth group for them to observe and learn from. These experiences for youth are highly valuable, and may drive long-term conservation benefits for monarchs. 

How big of an impact do logging and other threats to the winter habitat have on the population?

In 1986 a decree was set in place to protect the Monarch Butterfly Biosphere Reserve, which has reduced the amount of illegal logging significantly. Read more about threats to the overwintering sites in the North American Monarch Conservation Plan (pg 24).

What is known about the potential impacts of mosquito control on monarchs?

The potential impacts of mosquito control on monarchs will vary based on the control method used. A few papers on are available from the University of Minnesota Monarch Lab about non target effects on monarchs from the mosquito control chemicals Permethrin and Resmethrin.

Are there natural predators that kill monarch eggs, larvae, and adults?

Yes, learn more about monarch natural predators on the Monarch Lab website. The percentage of monarchs that survive from egg to adulthood is very low. Researchers agree that less than 10% of the eggs that are laid survive to become adult butterflies, and some feel that this number may be significantly under 10%. To account for low survival in the wild, female monarchs can lay 300-500 eggs in their lifetime. 

What are the current recommendations for minimizing pesticide drift onto monarch habitat?

The Natural Resources Conservation Service Wildlife Habitat Evaluation Guide recommends including a 125-foot pesticide free buffer adjacent to monarch or pollinator habitat to minimize impacts of drift. Using best practices when applying pesticides will further minimize the risk of drift. Drift distance will vary greatly depending on method of application and conditions during application.

When planting pollinator habitat adjacent to a road, how big of a concern is mortality by vehicle traffic?

While vehicle traffic is a contributor to adult monarch mortality, more research is needed on this issue to know the full extent. However, given the extreme loss of habitat that monarchs and others have faced, we feel confident that the benefits of planting pollinator habitat along roadsides outweigh the cost. You can read more on roadside threats and opportunities for pollinators in this literature review  for the Federal Highways Administration conducted by the Xerces Society. 

My milkweed habitat should be mowed to cut back the woody vegetation that is encroaching. Is there a safe time to do this that will be less harmful to monarchs?

Yes! The MJV has a handout called Mowing: Best Practices for Monarchs. We used citizen science data and ground-tested it with researchers and volunteers across the country to come up with recommendations for times when management activities may be safer for monarchs. It is important to note that this handout looks strictly at monarchs, so if you have prioritized additional plant or animal species to protect at your site, make sure to consider timing that works best for all! Because monarch timing can vary slightly from one year to the next, it is also important to keep an eye on the status of the migration through Journey North to see how this year's timing might be different from other years. Most importantly, avoid mowing or disturbing the entire habitat at once so that you leave untouched areas for wildlife using the habitat to recolonize.

What should I do if plants that I've purchased were treated with neonicotinoids or other pesticides? How should I avoid purchasing treated plants in the future?

When creating pollinator habitat it is important to minimize pollinator exposure to chemicals that have the potential to cause harm.  There are several steps that you can take as a consumer to reduce pollinator exposure to neonicotinoids and other pesticides:

Scenario 1: You have already purchased plants, but you don’t know if they were treated.  If you’re suspicious that recently purchased plants were treated, remove flowers for the first couple of years so that pollinators are not attracted to blooms. Neonicotinoid levels will diminish in the plant over time.  For caterpillar host plants like milkweed suspected of being treated, the safest option for would be to properly dispose of the plant and find sources you know are pesticide-free to replace them.  Alternatively, you could cover/tent plants for a year so that monarchs do not use them. By the next year, it is unlikely that there will be enough remaining pesticide residue to pose a problem to caterpillars. However, this is an active area of research and later findings might lead to changes in this recommendation.

Scenario 2: You’re planning to purchase milkweed and other wildflowers to support pollinators.  Sometimes plants are labeled as neonicotinoid- or pesticide-free, but not always. Even if plants are labeled as “Pollinator Plants” it is best to ask the grower or distributor you are purchasing from about the history of the plants. Ask if they were treated with any pesticides and if so, which ones. Express the importance of pesticide free plants to help plant producers understand the demand for pollinator-friendly plants in the marketplace. Be wise about purchasing plants, ask the appropriate questions, build a relationship with producers you trust, and encourage your community to support those producers you know are growing/selling neonicotinoid free plants.

Scenario 3: You’re maintaining pollinator habitat on your property.  As you maintain pollinator habitat on your property, do not use insecticides on your plants.  If you must treat, do not use neonics or other systemic insecticides, and avoid spraying when plants are in bloom, when pollinators are most drawn to them. The use of insecticidal soaps or horticultural oils can be used to control unwanted insects, but keep in mind that this treatment may harm or kill any beneficial insects present at the time of application, even if the plant is not in bloom.

What should I do if there are laws or ordinances that I feel are detrimental to monarchs and their habitat?

No matter what the scale, if you have concerns with rules or regulations, you should contact your elected officials to share your perspective and any evidence supporting your argument that could help effect change. Learn more about how to contact your elected officials on MJV's Advocate Page.

Habitat Conservation

What should I do if I can't find an appropriate source of local native milkweeds or nectar resources that are recommended for monarchs?

This reason for this problem comes back to the principles of supply and demand. The commercial availability of native milkweeds and nectar sources is driven by the demand for those resources and a response in the supply chain will not always be immediate. Producing native plant materials is a long-term process and can sometimes be a risky investment for plant producers if they aren't sure about the long-term demand for those plants/seeds. It is important that we continue to drive increasing demand for these native, locally sourced plant materials to increase their availability over time and hopefully to drive down the cost as well. Since supply is often limited for native milkweeds and nectar sources, get your orders/requests in early. If vendors sell out during the spring, they may begin taking pre-orders for the following fall or spring.

If you haven't already done so, make sure that your site is ready for planting. There are different methods for site preparation, such as solarization, you can use to ensure the area is as weed free as possible to increase the success of the native plants you are trying to establish. Even if native milkweeds are not available when you are ready to plant, establish a high-diversity mix with other native forbs and grasses. These habitats will still be beneficial to monarchs and other pollinators, and you can plan ahead to augment the habitat in years following with milkweed plants/plugs. Another option would be to use annuals or some sort of cover crop on the habitat area during that season. This could prevent weedy species or invasives from taking over a site that you have prepared for planting and will allow time for you to find an appropriate source of seeds or plants for the habitat. Depending on what is planted, it may also provide some floral resources for pollinators.

Can milkweed plants growing in backyards across the U.S. make a difference?

Yes! Everyone’s habitat makes a difference, especially when there are many together that start to build a connected network of habitats. Planting milkweed in your garden or yard creates much needed habitat for monarchs in your area, and allows them to live and reproduce to create the next generation of monarchs. It also raises awareness in your community and encourages others to plant milkweed themselves, which is how we can spread the word and get even more habitat created. Visit www.plantmilkweed.org to get started with your yard or garden milkweed plants

Is foraging habitat for the adults more important than milkweed during the fall migration?

Milkweed is important throughout the growing season, since monarch larvae continue to develop on the host plants as the migration begins. However, nectar sources, or foraging habitat for adults during the fall (southbound) migration are extremely important. Adult monarchs that eclose starting around mid-August are in a state of delayed maturation called reproductive diapause. They focus on nectaring to fuel their migration rather than breeding and laying eggs on milkweed. For this reason, nectar sources are more important for adult monarchs during the fall migration. All monarch habitats should include a mix of local, native milkweed and nectar plants appropriate to your region. A variety of nectar plants should be planted so that your garden is blooming all season long. For information on creating habitat for monarchs visit www.plantmilkweed.org.

Is the monarch migration at risk of extinction?

A recent publication indicates substantial probability for “quasi-extinction” of the Eastern monarch butterfly migratory population within 20 years if ambitious habitat restoration and conservation goals are not achieved. Quasi-extinction means that the population reaches levels that are so low that it would be unlikely to recover. To minimize this risk, national population targets have been set to restore the Eastern monarch overwintering population size to 6 hectares of space occupied in Mexico through the addition of habitat across North America, including about 1.5 billion additional milkweed stems. Achieving this population size may help the population rebound more readily after stochastic weather events, such as the major winter storm that occurred in the late winter/early spring 2016 at the overwintering sites in Mexico, which likely caused significant mortality of the butterflies remaining there. Read more here.

Is there any value of habitat that has nectar sources but no milkweed sources for monarchs? Or, is the push really to focus on milkweed in the habitat?

Monarchs need milkweed throughout the spring and summer to successful reproduce. However, in addition to milkweed plants, nectar sources are extremely important for adult monarchs throughout the breeing and migratory seasons. Nectar sources are of highest priority during the fall migration, when adults are storing energy to survive the winter at their overwintering locations. All habitat restoration efforts should plan for both milkweeds and nectar sources.

How can I fund my monarch project?

Large and small scale monarch conservation projects can benefit from financial support, either to enhance an existing site with native, locally sourced milkweeds or nectar sources, or to establish a new site from scratch. If you are looking to install or enhance habitat for monarchs and other pollinators but don't have the funds available to complete the project yourself, here are a few tips to consider when looking for funding. 

  • For small-scale garden habitats, the primary funding opportunities are local to your state or community. Some national garden grant opportunities may be available, but these opportunities are not consistently available and  may vary from one year to the next. Check the University of Minnesota Monarch Lab's list of garden grants from across the country. Search online for "garden grant" opportunities and find one that may apply to your area or planting objectives. Locally, you may also find support from a business or other local entity that may have resources to support community development or engagement.
  • It is important to connect with other stakeholders in your community that have similar conservation interests. These groups may have funding available for local projects, have information and expertise to share as your project progresses, and may be able to help you leverage opportunities for low-cost or free materials to use for your project. Connect with naturalist groups like Master Naturalists, Master Gardeners, Pheasants Forever, or Wild Ones chapters (among others!) who have similar interests. These groups could provide local seeds they have collected, or may have plant materials to transplant from existing gardens. 
  • Community scale projects or public projects may be able to work with local native plant producers to provide seeds or plant at low or no-cost. Talk with local nurseries to see if there are opportunities to work closely with them on these types of projects. 
  • For private landowners with a bit more acreage, conservation resources and funding opportunities are listed by state on this website: http://www.privatelandownernetwork.org/. These resources should be explored thoroughly for funding or cost share opportunities for your state or region.
  • The National Fish and Wildlife Foundation is currently operating a Monarch Butterlfy Conservation Fund for large projects, and typically have an annual request for proposals.
  • Also keep in mind that restoring habitat for monarchs has many co-benefits. Leverage other funding opportunities that prioritize migratory bird habitat, water quality, or another conservation initiative. If you recognize and make connections to multiple species and environmental benefits, you will broaden your opportunities to support a habitat restoration project, even if your primary goal is monarch conservation. Search to find conservation minded funding opportunities through trusts, foundations, or other entities.
What is the "Monarch Highway"?

Branded as the "Monarch Highway," this is an initiative launched in 2015 to create a multi-state partnership bringing together state transportation agencies and other partners along Interstate-35 (I-35) to catalyze conservation actions along the corridor and its neighboring communities that enhance habitat and engage people. The I-35 corridor, or the "Monarch Highway," runs along the central flyway of the monarch migration in the states of Minnesota, Iowa, Missouri, Kansas, Oklahoma, and Texas.
This project aims to promote awareness of monarchs and other pollinators and assist individual state efforts to enhance vegetation management practices. The project hopes to serve as a national model for native pollinator habitat restoration along transportation byways through private sector and philanthropic enhancement of state and local activities. This idea builds upon the past success of the 1995 Prairie Passage Route Partnership formed by the state departments of transportation along I-35. A number of these states remain national leaders in roadside integrated vegetation management and prairie restoration. Reinvigorating the focus on the I-35 corridor will facilitate concentrated regional coordination and action to make a visible difference in working landscapes and communities along the corridor.
The idea for a "Monarch Highway" partnership came from a federal strategy to promote the health of honey bees and other pollinators released in 2015. The strategy called for the idea of a "Monarch Highway" along I-35 and directed the U.S. Department of Transportation to work with state departments of transportation to promote pollinator-friendly practices and corridors. Later in 2015, the White House Office of Science and Technology Policy and U.S. Department of Transportation organized a summit of state transportation leaders to advance regional and statewide efforts to promote and improve pollinator habitats on transportation rights-of-way, including the "Monarch Highway."
In May 2016, the six states along I-35 signed an agreement establishing I-35 as the "Monarch Highway" and furthering their commitment to leverage transportation rights-of-ways for monarch and pollinator habitat while also developing a public outreach and awareness effort. The memorandum of agreement was signed during the AASHTO Board of Directors meeting in Des Moines. Signatories included FHWA Administrator Greg Nadeau and senior executives from Minnesota, Iowa, Missouri, Kansas, Oklahoma and Texas. The agreement establishes "a cooperative and coordinated effort to establish best practices and promote public awareness of the monarch butterfly and other pollinator conservation." The parties also will work together to develop a unified branding for I-35, informally naming it the "Monarch Highway."

Should I purchase monarchs for release?

We do not recommend buying monarchs commercially to raise/release into your garden or other habitat. We feel that creating, restoring, enhancing and maintaining habitat for monarchs and other pollinators is the best conservation strategy. Habitat is beneficial to more than just monarchs, and encourages a healthy ecosystem with diverse pollinators, which are essential to our economy. While monarchs may not always find or utilize every milkweed patch, increasing habitat everywhere helps to ensure connectivity of habitats and increases the likelihood that monarchs will find suitable breeding grounds. Aside from concerns about the purchase and release of commercially raised monarchs, one of the major factors influencing the decline in the first place is broad scale loss of habitat. We must work to restore habitat on the landscape so that the wild population can rebound. 

For more details on concerns expressed by some monarch researchers, view this statement: http://monarchlab.org/biology-and-research/monarch-rearing/captive-breeding-and-releasing-monarchs/. (Note, this statement does not necessarily reflect the views and opinions of all MJV partners).

Should I use solarization to prepare my site for planting monarch habitat?

Solarization is one method of preparing a site for planting. This guide by the Xerces Society outlines restoring habitats from seed, and includes the solarization process. One of the webinars in the MJV Monarch Conservation Webinar Series also addresses this topic. 

What are the recent tri-national efforts and strategies related to monarch conservation?

In the U.S. a High Level Working group for monarchs released a national strategy for protecting monarchs and other pollinators. This group will work collaboratively with working groups in Canada and Mexico to develop a trinational action plan for monarch conservation.

What does it mean to use locally sourced plants or seeds for habitat restoration?

Wild Ones provides a great overview on what it means to plant local ecotype plants and what the benefits of doing so are. Read more here.

My milkweed habitat should be mowed to cut back the woody vegetation that is encroaching. Is there a safe time to do this that will be less harmful to monarchs?

Yes! The MJV has a handout called Mowing: Best Practices for Monarchs. We used citizen science data and ground-tested it with researchers and volunteers across the country to come up with recommendations for times when management activities may be safer for monarchs. It is important to note that this handout looks strictly at monarchs, so if you have prioritized additional plant or animal species to protect at your site, make sure to consider timing that works best for all! Because monarch timing can vary slightly from one year to the next, it is also important to keep an eye on the status of the migration through Journey North to see how this year's timing might be different from other years. Most importantly, avoid mowing or disturbing the entire habitat at once so that you leave untouched areas for wildlife using the habitat to recolonize.

Is it better to plant seeds or plugs for my monarch habitat project?

Many factors play into the decision of whether seeds or plugs, or some combination of the two, are more appropriate for your habitat project. Seeds are often the most economical option, but establishment may be more successful with planting plugs if your project budget can handle it. If an area is large, using a diverse native seed mix will require less time, whereas it will require significantly more time and labor if transplanting plugs throughout the entire area. For smaller areas, like gardens, placement of different species within the habitat might be more important to you and in this case, plugs might be a more appropriate option (because you have more control than a seed mix). Plugs have a head start and generally establish and reach maturity more quickly than seeds.

You can explore what works best for different species, and could find that a combination of techniques works best, depending on the species you are planting, the location and size of the project, the project budget, and the labor or equipment resources available to support the project. To save cost but maintain the higher success of plug establishment, some start seeds indoors (or in controlled containers outdoors) which they later transplant as plugs. Some plant a diverse seed mix and supplement it with plugs. Others stick to just using one technique or the other (plugs or seeds). Each habitat project is unique and there is not one best option that fits the needs of all.

A consideration for all habitat projects is site preparation prior to planting. To give seedlings and plugs the best chance of survival, it is important to keep weed pressure low. Ensuring that weeds and weed seeds are eradicated from the site prior to planting will improve the success of establishing native plants. 

Visit our resources page for additional information on this topic.

What should I do if there are laws or ordinances that I feel are detrimental to monarchs and their habitat?

No matter what the scale, if you have concerns with rules or regulations, you should contact your elected officials to share your perspective and any evidence supporting your argument that could help effect change. Learn more about how to contact your elected officials on MJV's Advocate Page.

Where can I get information on creating interpretive signs for my monarch habitat?

Whether it's a habitat in your yard, a community garden, or a roadside or utility right-of-way, posting signs helps draw attention to the value of that habitat for monarchs and other pollinators, or any other suite of species that may use that habitat. We’ve compiled some existing signs from MJV partners that might be useful for your site, available on our website: http://monarchjointventure.org/resources/signs-and-displays/
 

How can I get involved in monarch conservation in Canada?

Creating habitat that includes native milkweeds and nectar plants is a common goal between Canada and the United States. In addition, many monarch citizen science programs are relevant across North America.  Here is a Management Plan for Monarchs in Canada (Environment Canada): https://www.registrelep-sararegistry.gc.ca/virtual_sara/files/plans/mp_monarch_e_proposed.pdf

Some organizations in Canada that have been working on monarch conservation issues in Canada include (but are not limited to):

Are there concerns with illegal logging in the monarch overwintering habitat in Mexico?

Most importantly, logging that occurs in the core zone of the Monarch Butterfly Biosphere Reserve is illegal. It is neither widespread nor common, but just as illegal things occur in the U.S., illegal things occur in Mexico when people profit economically by committing crimes. Both the local people and the government work hard to enforce the laws, but the area is huge, there is some collusion with some community members, and some large cartels are getting involved in illegal lumbering. There is also a large demand for the lumber, some of which ends up in the US. There are many organizations working together with the government and communities in the area to reduce and stop illegal logging. You can find out more about the work our partner the Monarch Butterfly Fund is doing in this area here: http://monarchconservation.org/

What can I do to support monarchs and pollinators with a few acres of land?

Create habitat with a mix of native wildflowers (including milkweeds) and grasses. You can plant native plants in a more typical garden setting, or plant a prairie garden or natural area. Think about areas on your yard that could be maintained with native prairie plants - they don't always have to be gardens! Native prairie plants, once established, require much less maintenance than a typical mowed lawn, and provide tremendous benefits to local pollinators. Find locally sourced native plant materials, and collaborate with groups like Pheasants Forever, Wild ones, or Master Naturalists/Master Gardeners to help plant and maintain the habitat! For more resources visit our downloads and links page.

What do monarchs eat?

In North America, monarch caterpillars rely on milkweed (Asclepias genus) and a few closely related genera to grow and develop. Female monarchs use a series of cues to find milkweed and lay their eggs on the leaves of this plant.  After the egg hatches, the caterpillar feeds on milkweed exclusively, and does not leave the host plant until it is ready to pupate. Therefore, milkweed is known as the “host plant” for monarchs. Adult monarchs drink the nectar of many species of flowering plants. It is important for monarch habitat to provide food sources for both caterpillars and adult butterflies, so plant native milkweed and nectar flowers in your habitat! Answer adapted from the University of Minnesota Monarch Lab FAQ.

Milkweed

How do I get rid of pests, like aphids, from my garden or habitat? Are they hurting my monarchs?

Many people are concerned about infestations of insects in their garden or habitat; we get the most questions about aphids. There are a few key points to remember when thinking about pest control. First, with good quality habitat comes a higher diversity of insects using the site. This diversity is providing resources for a wide variety of wildlife using the habitat and overall contributes to the health of the ecosystem. Some of these insects may compete with monarchs for milkweed, or even kill monarchs, but we can trust that in a healthy and diverse ecosystem/habitat, some monarchs will evade predators and contribute to the population. Second, remember that almost all insecticides will kill more than just the target species. If you spray an area with insecticide to kill aphids, other insects (including monarchs) that are in the area will be affected. For this reason, we don't recommend using insecticides in your monarch or pollinator habitat.

If you have a severe issue with aphids on your milkweeds, the safest way to remove them is manually. While a high concentration of aphids on your milkweed may look "bad", these insects are not necessarily causing harm to monarchs; unless they are in extremely high density, there are usually not enough aphids to kill the plant. You can squish the aphids and then rinse the plants with water to dislodge them from the plant. Make sure to check for monarch eggs and caterpillars first! A mild solution of dish soap and water can also be used to kill aphids on milkweed plants (again, after monarchs have been removed). Spraying this solution directly onto the aphids effectively kills the insects. Rinse the plants about a day after they've been treated with this insecticidal soap to remove any residue or dead aphids. This method is only effective when the solution directly hits the target insects; it acts by blogging the spiracles, so the residue will not kill insects. You can find a variety of recipes for home made insecticidal soap online, using simple ingredients typically found in your home.

How do I choose which species to plant for monarchs and where can I find local sources?

Native milkweeds and nectar plants are essential for monarchs. Monarchs need milkweed for egg laying and larval development and need nectar resources to support adult butterflies during breeding and migration. Both should be included in any monarch habitat. We recommend planting native, locally sourced species that are well-adapted for your region and more likely to thrive in your area's conditions. You can find information about how to choose which milkweed and nectar resources are right for you from our www.plantmilkweed.org website. This website also provides guidance on locating appropriate seed and plant materials near you, and considerations for different types of restoration or enhancement projects, like gardens or larger natural areas.

Does the decline in available milkweed coincide with greater use of genetically modified corn and soybeans?

Yes, research by Dr. John Pleasants and Dr. Karen Oberhauser indicate that the loss of agricultural milkweeds is a major contributor to the decline in the monarch population

Can milkweed plants growing in backyards across the U.S. make a difference?

Yes! Everyone’s habitat makes a difference, especially when there are many together that start to build a connected network of habitats. Planting milkweed in your garden or yard creates much needed habitat for monarchs in your area, and allows them to live and reproduce to create the next generation of monarchs. It also raises awareness in your community and encourages others to plant milkweed themselves, which is how we can spread the word and get even more habitat created. Visit www.plantmilkweed.org to get started with your yard or garden milkweed plants

Where can I find free or low cost milkweeds and nectar plants?

Here is more information on finding funding for your monarch project. There is also information about finding milkweeds native to your area on our website, www.plantmilkweed.org. You may also apply for Free Milkweeds for Restoration Projects through Monarch Watch's Milkweed Market. 

Don't forget to check with friends, neighbors, or your local garden club to see if anyone has seeds from native milkweeds or other wildflowers that they have collected and would be willing to share. Some forbs (flowering plants) may also be easy to split or transplant if someone you know is looking to get rid of them.

Do you have tips for growing milkweed? What do you recommend for me to be successful?

The Xerces Society provides an entire FAQ all about milkweeds! Read this for more valuable information on growing and establishing milkweeds. Xerces Milkweed FAQ 

Is milkweed harmful to grazing livestock?

Milkweed does contain toxic cardiac glycosides, but rarely pose a significant threat to people or animals. A small taste of milkweed is typically not fatal to animals, but can be dangerous if large quantities are consumed. If sufficient forage is available in grazing lands, milkweeds are generally not sought after. According to the USDA, poisoning typically occurs in areas of poor forage where milkweed is abundant. Prepared feeds and hay should not contain high concentrations of milkweed. For more information, please refer to our MJV handout: Monarch and Milkweed Misconceptions.

Is foraging habitat for the adults more important than milkweed during the fall migration?

Milkweed is important throughout the growing season, since monarch larvae continue to develop on the host plants as the migration begins. However, nectar sources, or foraging habitat for adults during the fall (southbound) migration are extremely important. Adult monarchs that eclose starting around mid-August are in a state of delayed maturation called reproductive diapause. They focus on nectaring to fuel their migration rather than breeding and laying eggs on milkweed. For this reason, nectar sources are more important for adult monarchs during the fall migration. All monarch habitats should include a mix of local, native milkweed and nectar plants appropriate to your region. A variety of nectar plants should be planted so that your garden is blooming all season long. For information on creating habitat for monarchs visit www.plantmilkweed.org.

Do some areas already have ‘enough’ milkweed habitat?

Healthy and abundant habitat is essential for monarch and pollinator conservation. For monarchs, this habitat should contain milkweed because it is an essential host plant for their larvae to eat. While habitat without milkweed can also provide floral/nectar resources for monarchs (which are also very important), that habitat would not be able to support immature monarchs during their reproductive season. Thus, a habitat with a balance of both native milkweeds and other nectar plants will benefit monarchs and a variety of other pollinators and wildlife. Since one main goal of habitat restoration is to create an ecosystem that is able to sustain long-term and continue providing benefits to the organisms using the site, it is important that these habitats are diverse. Milkweeds are a part of this ecosystem and provide benefits to more than monarchs, so should be included in all habitat restoration projects, as should other wildflowers. Another consideration is habitat fragmentation, and what this means for monarchs in search of suitable breeding areas. Including and increasing habitat that includes milkweed across the landscape, regardless of area, will help to ensure that those monarchs in search of breeding habitat will find it more easily. Recovering from the recent record low population size may not happen in just a few years, so the more habitat available for reproduction, the better likelihood monarchs have of a population rebound.

My monarchs are eating dill or parsley! What's going on?

What you are looking at is not a monarch, since monarchs only eat milkweed (genus Asclepias). We get this observation and question quite often, because the caterpillars of the black swallowtail butterfly resemble a monarch caterpillar. Black swallowtail larvae feed on a variety of different host plants, but cultivated garden plants like dill, parsley, celery, and fennel are a few on the list. If you come across a caterpillar that you don't know, try identifying the host plant that it is on. This may help you in determining what Lepidoptera (butterfly or moth) species you are dealing with!

Do monarchs utilize different types of milkweed? Which are preferred?

Yes, there are many species of milkweed utilized by monarchs. Most species that are available and native to your region can be used by monarchs. The Monarch Joint Venture provides an overview of the priority species that we recommend for each region.

Do we understand site characteristics necessary for successfully transplanting milkweed?

See the Xerces Society’s Milkweeds: A conservation practitioner’s guide.

What are the potential problems associated with planting tropical milkweeds?

Please see the Monarch Joint Venture Fact Sheet and our Q&A with monarch and tropical milkweed experts about the potential risks of growing exotic milkweed for monarchs.

What should I do with my milkweed seeds?

If you have extra native milkweed seeds that you would like to share, here are some considerations: 

  1. Native milkweeds need to undergo cold/moist stratification or vernalization before they are able to germinate, so if you are sharing your seeds with others, make sure that you let them know the status of this so they know how to prepare or store the seeds prior to planting.
  2. This MJV FAQ and this article from the Native Plant Society of Texas discuss how to harvest milkweed seeds. 
  3. To build habitat connectivity for monarchs and other pollinators, offer your local, native milkweed or nectar plant seeds to friends and neighbors and encourage them to plant pollinator habitat. 
  4. To help strengthen commercial milkweed availability, connect with local native plant or seed vendors who may be interested in your seeds. 
  5. Connect with various community groups or chapters who own or have access to land where seeds may be put to good use. These include but are not limited to Pheasants Forever, Wild Ones, Master Gardeners/Naturalists, Extension programs, golf courses, archery or gun clubs, parks, schools, natural resources groups (soil and water conservation districts, etc.),  
  6. The Milkweed Market can use your native seeds. This program collects donated milkweed seeds and grows regionally appropriate milkweed plugs, which they distribute back to the region the seeds originated.
  7. Contribute to the national seed bank by participating in the Bureau of Land Management's Seeds of Success program. For more information about the national seed strategy, you can view the 2015 document here.     

Remember, the best thing you can do with your seeds is to plant them locally!

What should I do if plants that I've purchased were treated with neonicotinoids or other pesticides? How should I avoid purchasing treated plants in the future?

When creating pollinator habitat it is important to minimize pollinator exposure to chemicals that have the potential to cause harm.  There are several steps that you can take as a consumer to reduce pollinator exposure to neonicotinoids and other pesticides:

Scenario 1: You have already purchased plants, but you don’t know if they were treated.  If you’re suspicious that recently purchased plants were treated, remove flowers for the first couple of years so that pollinators are not attracted to blooms. Neonicotinoid levels will diminish in the plant over time.  For caterpillar host plants like milkweed suspected of being treated, the safest option for would be to properly dispose of the plant and find sources you know are pesticide-free to replace them.  Alternatively, you could cover/tent plants for a year so that monarchs do not use them. By the next year, it is unlikely that there will be enough remaining pesticide residue to pose a problem to caterpillars. However, this is an active area of research and later findings might lead to changes in this recommendation.

Scenario 2: You’re planning to purchase milkweed and other wildflowers to support pollinators.  Sometimes plants are labeled as neonicotinoid- or pesticide-free, but not always. Even if plants are labeled as “Pollinator Plants” it is best to ask the grower or distributor you are purchasing from about the history of the plants. Ask if they were treated with any pesticides and if so, which ones. Express the importance of pesticide free plants to help plant producers understand the demand for pollinator-friendly plants in the marketplace. Be wise about purchasing plants, ask the appropriate questions, build a relationship with producers you trust, and encourage your community to support those producers you know are growing/selling neonicotinoid free plants.

Scenario 3: You’re maintaining pollinator habitat on your property.  As you maintain pollinator habitat on your property, do not use insecticides on your plants.  If you must treat, do not use neonics or other systemic insecticides, and avoid spraying when plants are in bloom, when pollinators are most drawn to them. The use of insecticidal soaps or horticultural oils can be used to control unwanted insects, but keep in mind that this treatment may harm or kill any beneficial insects present at the time of application, even if the plant is not in bloom.

What is the best time to plant milkweed seeds?

Pollinator Plants of the Central US provides an overview of milkweed establishment practices for the lower Midwest and central United States. According to the document, milkweed seed should ideally be planted in the fall. While some seed predation will occur, exposure to cold temperatures and moist conditions during winter will stimulate germination. Spring planting is also possible but artificial stratification of the seed is recommended to enhance germination.

Where can I get milkweed seeds or plants that are most appropriate for my area?

Our web page, www.plantmilkweed.org, has many great resources and tips for locating native milkweed seeds and plugs across the U.S. The Xerces Society's Milkweed Seed Finder and Monarch Watch Milkweed Market provide a directory of vendors that distribute native milkweed seeds and/or plugs. In addition, the Milkweed Market offers trays of native milkweed plugs for purchase for different regions of the country (regional availability varies). We recommend using native milkweeds in all gardening or restoration projects. The commercial availability of native milkweed seeds or plants can be limited (varies by region), so to help build this market (increasing availability and driving down cost) we strongly encourage your support of the commercial market through purchasing native plant materials from a local native plant or seed producer.

Why does my milkweed look diseased or yellow?

Disease isn't always the culprit when milkweed doesn't appear healthy. If there is a possibility that herbicide was applied in the general vicinity, this could potentially be a cause for unusual or sick-looking milkweed. If spray drift is unlikely the cause, there are many different diseases that affect milkweed, including everything from fungi to viruses. One common bacterial disease is called milkweed yellows phytoplasma. The University of Minnesota Monarch Lab has a post about how to identify and deal with this particular milkweed disease.

It can be difficult to identify what is affecting your specific plants, as there is no comprehensive diagnostic manual for milkweed diseases. The Xerces Society Milkweed FAQ provides some general advice about dealing with diseased milkweeds:

"When milkweeds in home gardens or landscape features display symptoms of infection, removing and disposing of the diseased tissue will help prevent the infection from spreading to healthy plants."

Why are caterpillars disappearing from my milkweed patch?

There are a number of potential reasons for this. If disappearing caterpillars are 5th instar caterpillars, odds are they moved away from your milkweeds to find a safe place to form their chrysalis (they typically do not pupate on milkweed plants). If earlier instars or eggs are disappearing, a more likely culprit is a monarch predator. You can read more about natural enemies on our website. Researchers agree that less than 10% (with some studies as low as 2%) of monarch eggs reach adulthood. 

How can I grow milkweed from seed?

Milkweed seed can be planted directly in soil, or started indoors. You can sow milkweed seeds by scattering them on the soil surface 1/4-1/2 inch apart, and then cover them with about 1/4 inch of additional soil. Water the area frequently after planting until plants become established. Many species need to be vernalized (cold treated) before planting. Vernalized seeds can be planted in the spring after the danger of frost has passed. Non-vernalized seeds can be planted in the fall, and nature will provide the cold treatment. See Monarch Watch's milkweed propagation guide for further recommendations, information on vernalization and instructions for starting milkweed seeds indoors.  Also watch our Monarch Conservation Webinar: Growing Milkweed for Monarch Conservation (scroll down to May 2016) to hear from Chip Taylor of Monarch Watch on milkweed growing techniques and best practices. For further details on milkweed growing and conservation use, visit the Xerces Society's Milkweed Practicitoner Guide, which is a complete guide to milkweeds, including biology/ecology, propagation, benefits to wildlife, and use in restoration projects.

What is the most appropriate time to cut tropical milkweed back?

It is recommended to prune the milkweed stalks to about 6 inches in height during the fall and winter months to discourage monarchs from establishing winter-breeding colonies. Cutting back the milkweed will also help to eliminate OE spores that may be present on the plant. Re-cut the milkweed every few weeks as leaves re-sprout. Tropical milkweed might pose fewer problems in the northern monarch breeding range because it dies back naturally when it freezes.

These recommendations are not applicable in south Florida (south of Orlando), where a distinctive, non-migratory population of monarchs has long been established. However, native milkweed planting is still encouraged in this area.

For more information on tropical milkweed, read the our handout on the topic.

What's eating my milkweed?

Despite milkweed's toxicity, there are many creatures other than monarchs that eat the leaves of this amazing plant. Deer and rabbits have been reported to eat milkweed leaves, and there are many other insects that feed on milkweed such as milkweed bugs, tussock moths, queen butterfly larvae, and more. Nectar and pollen from milkweeds are important food sources for many pollinators, in addition to monarch butterflies. In addition to attracting pollinators, milkweeds support a wide variety of insects that attack crop and garden pests (Milkweed: A Conservation Practitioners Guide). For more information on the milkweed ecosystem, visit http://monarchjointventure.org/resources/downloads-and-links/ and click on Milkweed Resources. A great field guide to what's in the milkweed patch is Milkweed, Monarchs and More (Ba Rea, Karen Oberhauser, and Michael Quinn).

What do monarchs eat?

In North America, monarch caterpillars rely on milkweed (Asclepias genus) and a few closely related genera to grow and develop. Female monarchs use a series of cues to find milkweed and lay their eggs on the leaves of this plant.  After the egg hatches, the caterpillar feeds on milkweed exclusively, and does not leave the host plant until it is ready to pupate. Therefore, milkweed is known as the “host plant” for monarchs. Adult monarchs drink the nectar of many species of flowering plants. It is important for monarch habitat to provide food sources for both caterpillars and adult butterflies, so plant native milkweed and nectar flowers in your habitat! Answer adapted from the University of Minnesota Monarch Lab FAQ.

How can I tell if a plant is milkweed or dogbane?

Another plant, dogbane (Apocynum cannabinum), looks strikingly similar to common milkweed (Asclepias syriaca). This look-alike can leave people disappointed if they're expecting monarchs on their milkweed, but it turns out not to be the right plant! Here's a few ways they're similar, and how to tell them apart.

Similarities: Both plants have milky sap if you break off a leaf, and their growth pattern is very similar. Both have opposite and oval shaped leaves.

Differences: Common milkweed has a hairy stem, unlike dogbane. When mature, the dogbane stem branches in the upper portion of the plant. The flowers also look quite different. Common milkweed flowers are pinkish, large and ball shaped, whereas dogbane flowers are whitish green and in small clusters.

How can I collect, save, and share my milkweed seeds with friends and family?

If you want to harvest your milkweed seeds to share or donate, here are a few things to keep in mind:

  • Remember to only collect local, native milkweed seeds!
  • Always identify the species prior to harvesting and clearly mark the container you keep them in (Suggested label: Your name, date, species common and/or scientific name, location of collection)
  • It’s best to only collect a portion of the seeds in the area you find milkweed so that the milkweed can continue to propagate your area! (Recommendation: collect 1/3 of the seeds and leave 2/3)
  • Know when to collect! This is important because the seeds need to be ripe in order to germinate. If the seeds are white or pale, they are not ready yet. Keep an eye out for browning on the pod. When ready, the seed pods will easily split open.
  • After collecting the seed pods, leave them out to dry in an open, dry area. Once the pods are dry, open them to collect the seeds. There will be a silk-material that needs to be removed before storing. You can remove this by hand or by placing the seeds and silk material in a paper bag. Shake vigorously to separate the seeds. Cut a small hole in the bottom corner to shake out seeds. To see how to remove the silk by hand, watch this video.
  • Once the seeds are stripped of the silk material, store them in a cool, dry place away from mice and insects! (Plastic baggies or glass or plastic jars work well.)

You can also check out this article from the Native Plant Society of Texas for more information on how to harvest milkweed seeds. 

Nectar Plants

How do I choose which species to plant for monarchs and where can I find local sources?

Native milkweeds and nectar plants are essential for monarchs. Monarchs need milkweed for egg laying and larval development and need nectar resources to support adult butterflies during breeding and migration. Both should be included in any monarch habitat. We recommend planting native, locally sourced species that are well-adapted for your region and more likely to thrive in your area's conditions. You can find information about how to choose which milkweed and nectar resources are right for you from our www.plantmilkweed.org website. This website also provides guidance on locating appropriate seed and plant materials near you, and considerations for different types of restoration or enhancement projects, like gardens or larger natural areas.

Where can I find free or low cost milkweeds and nectar plants?

Here is more information on finding funding for your monarch project. There is also information about finding milkweeds native to your area on our website, www.plantmilkweed.org. You may also apply for Free Milkweeds for Restoration Projects through Monarch Watch's Milkweed Market. 

Don't forget to check with friends, neighbors, or your local garden club to see if anyone has seeds from native milkweeds or other wildflowers that they have collected and would be willing to share. Some forbs (flowering plants) may also be easy to split or transplant if someone you know is looking to get rid of them.

Will monarchs use all types of flowers for nectar, or are there specific types that they prefer?

Adult monarchs nectar from a variety of blooming plants. Most importantly, make sure that there is nectar available throughout the growing season by providing a highly diverse foraging area. Some species are favored over others, depending on your region. Lists of recommended nectar plants for pollinators by region can be found at The Xerces Society and the Pollinator Partnership. NRCS is also working with the Xerces Society to develop preferred lists of nectar plants by region that are specific to monarchs.

What should I do if plants that I've purchased were treated with neonicotinoids or other pesticides? How should I avoid purchasing treated plants in the future?

When creating pollinator habitat it is important to minimize pollinator exposure to chemicals that have the potential to cause harm.  There are several steps that you can take as a consumer to reduce pollinator exposure to neonicotinoids and other pesticides:

Scenario 1: You have already purchased plants, but you don’t know if they were treated.  If you’re suspicious that recently purchased plants were treated, remove flowers for the first couple of years so that pollinators are not attracted to blooms. Neonicotinoid levels will diminish in the plant over time.  For caterpillar host plants like milkweed suspected of being treated, the safest option for would be to properly dispose of the plant and find sources you know are pesticide-free to replace them.  Alternatively, you could cover/tent plants for a year so that monarchs do not use them. By the next year, it is unlikely that there will be enough remaining pesticide residue to pose a problem to caterpillars. However, this is an active area of research and later findings might lead to changes in this recommendation.

Scenario 2: You’re planning to purchase milkweed and other wildflowers to support pollinators.  Sometimes plants are labeled as neonicotinoid- or pesticide-free, but not always. Even if plants are labeled as “Pollinator Plants” it is best to ask the grower or distributor you are purchasing from about the history of the plants. Ask if they were treated with any pesticides and if so, which ones. Express the importance of pesticide free plants to help plant producers understand the demand for pollinator-friendly plants in the marketplace. Be wise about purchasing plants, ask the appropriate questions, build a relationship with producers you trust, and encourage your community to support those producers you know are growing/selling neonicotinoid free plants.

Scenario 3: You’re maintaining pollinator habitat on your property.  As you maintain pollinator habitat on your property, do not use insecticides on your plants.  If you must treat, do not use neonics or other systemic insecticides, and avoid spraying when plants are in bloom, when pollinators are most drawn to them. The use of insecticidal soaps or horticultural oils can be used to control unwanted insects, but keep in mind that this treatment may harm or kill any beneficial insects present at the time of application, even if the plant is not in bloom.

What do monarchs eat?

In North America, monarch caterpillars rely on milkweed (Asclepias genus) and a few closely related genera to grow and develop. Female monarchs use a series of cues to find milkweed and lay their eggs on the leaves of this plant.  After the egg hatches, the caterpillar feeds on milkweed exclusively, and does not leave the host plant until it is ready to pupate. Therefore, milkweed is known as the “host plant” for monarchs. Adult monarchs drink the nectar of many species of flowering plants. It is important for monarch habitat to provide food sources for both caterpillars and adult butterflies, so plant native milkweed and nectar flowers in your habitat! Answer adapted from the University of Minnesota Monarch Lab FAQ.

Citizen Science

How can I connect with a citizen science group?

Check out the summary of citizen science projects provided on the MJV website. Sign up or email project leaders for more information.

How can I get my school, students or community involved in monarch conservation?

There are many ways for you and your community to get involved with monarch conservation! Visit our Get Involved page to find the right way for you to help protect monarchs.

How do you check the butterflies for OE infection?

Sampling involves capturing or raising adult monarchs and pressing clear tape against the butterfly's abdomen to collect parasite spores. MonarchHealth is a project in which volunteers sample wild monarch butterflies to help track the spread of this protozoan parasite across North America.

My monarchs are eating dill or parsley! What's going on?

What you are looking at is not a monarch, since monarchs only eat milkweed (genus Asclepias). We get this observation and question quite often, because the caterpillars of the black swallowtail butterfly resemble a monarch caterpillar. Black swallowtail larvae feed on a variety of different host plants, but cultivated garden plants like dill, parsley, celery, and fennel are a few on the list. If you come across a caterpillar that you don't know, try identifying the host plant that it is on. This may help you in determining what Lepidoptera (butterfly or moth) species you are dealing with!

What are the benefits and problems with raising and releasing monarchs?

Raising monarchs can be a wonderful educational tool and is a great way to inspire students to care about conservation. However, from a habitat conservation perspective, raising monarchs for release to bolster the population may have some disadvantages. Monarchs typically do not live in high densities in the wild, so they are prone to disease and infections when raised in captivity in large quantities. If breeding/migrating habitat is not increased simultaneously, raising and releasing monarchs may have minimal impact on the population if there isn't enough suitable habitat to support increased monarch numbers (due to raising). Lastly, research has show that some insects adapt to captive rearing conditions in as little as a few generations and thus, may be less apt to survive in wild conditions. For these reasons, we do not recommend captive rearing as a means to supplement wild monarch populations. Capturing monarchs from the wild, raising and releasing them locally, as well as keeping numbers low and conditions clean are effective recommendations for raising monarchs for educational purposes. See our flyer on Rearing Monarchs Responsibly for more detailed information.

How does monarch tagging work?

The purpose of tagging monarchs is to associate the location of original capture with the point of recovery for each butterfly. The data from these recaptures are used to determine the pathways taken by migrating monarchs, the influence of weather on the migration, the survival rate of the monarchs. Coded tags are attached to monarchs when they are captured before or during their southbound migration, and recovered when monarchs are re-sighted or found throughout the migration or overwintering season. Citizen scientists record the date, location, monarch gender, and unique tag number for each fall-migrating monarch that they tag and then submit these data to be used in research. The tags and tagging process do not harm the butterflies, and the data collected have the potential to answer many important questions about monarch biology and conservation. Monarch Watch, the Southwest Monarch Study, and Monarch Alert all have monarch tagging programs and are always looking for more citizen scientists; find the program that’s best for you and get involved!

Are there already made presentations available that I can use to help spread the word about monarch conservation?

Yes! The MJV has presentations about monarchs available for you to download and use in your own educational events. Just visit our Educate Others page to download them from Google Drive.

How can I get involved in monarch conservation in Canada?

Creating habitat that includes native milkweeds and nectar plants is a common goal between Canada and the United States. In addition, many monarch citizen science programs are relevant across North America.  Here is a Management Plan for Monarchs in Canada (Environment Canada): https://www.registrelep-sararegistry.gc.ca/virtual_sara/files/plans/mp_monarch_e_proposed.pdf

Some organizations in Canada that have been working on monarch conservation issues in Canada include (but are not limited to):

What is Citizen Science?

There is a long history of public participation in science. Prior to the late 19th century, most scientific research was conducted by untrained, yet passionate, citizens. Today, we use the term citizen scientist to describe volunteers who collect data for research but who are not professional scientists.

Citizen science and monarch monitoring have been closely tied together for years. Starting in the 1950s, Dr. Fred Urquhart’s “Insect Migration Association” involved hundreds of volunteers in a search of the then mysterious overwintering grounds of migrating monarchs. This tagging project allowed Urquhart to track the flights of individual butterflies, and ultimately led to the 1975 discovery that monarchs from the northern U.S. and southern Canada were overwintering in central Mexico.

Public involvement in monarch citizen science programs has been growing since 1990. Several citizen science programs focus on different aspects of monarch biology, including migration, population dispersal, parasites, and overwintering. Find out more about them here.

Migration

Are the western and eastern populations genetically isolated, or do they sometimes mix during migration?

The eastern and western monarch populations are not genetically different. The eastern population refers to the monarchs that overwinter in Mexico, and the western population refers to the monarchs that overwinter along the Pacific Coast. There is evidence of interchange between the eastern and western populations, perhaps when individuals cross the Rocky Mountains, when butterflies fly from the western U.S. to the Mexican wintering sites, or butterflies from the Mexican sites fly into the western U.S. Learn more about monarch migration on the biology page of our website.

Do monarchs return to the same areas when they are traveling north?

As long as milkweed continues to be available during the subsequent breeding season, monarchs (not necessarily the same ancestral line) may utilize that site year after year. However, very little is known about whether monarchs return to the same breeding locations as their ancestors.

Is the monarch migration at risk of extinction?

A recent publication indicates substantial probability for “quasi-extinction” of the Eastern monarch butterfly migratory population within 20 years if ambitious habitat restoration and conservation goals are not achieved. Quasi-extinction means that the population reaches levels that are so low that it would be unlikely to recover. To minimize this risk, national population targets have been set to restore the Eastern monarch overwintering population size to 6 hectares of space occupied in Mexico through the addition of habitat across North America, including about 1.5 billion additional milkweed stems. Achieving this population size may help the population rebound more readily after stochastic weather events, such as the major winter storm that occurred in the late winter/early spring 2016 at the overwintering sites in Mexico, which likely caused significant mortality of the butterflies remaining there. Read more here.

It will freeze soon in my area, and I'm still seeing monarch caterpillars. Will they survive? What should I do?

In order for an adult monarch to fly, temperatures need to be above 55 degrees Fahrenheit. While monarch eggs and caterpillars can survive some exposure to cold, these cooler temperatures slow their development time and prolonged exposure may cause sub-lethal effects (e.g. monarchs may take longer to develop, leaving them more vulnerable to disease and predation). 

Since there is not a distinct boundary separating breeding and migratory generations, there will be caterpillars that are developing late into the season as temperatures decrease and milkweed ages or senesces. Not all of them will survive. In many cases, the milkweed plants (and caterpillar food source) may be more vulnerable to freezing temperatures than the caterpillars themselves. Similarly, killing frosts can eliminate remaining nectar plant species that are in bloom, which feed fall migratory adult monarchs. These late season monarchs have a lower chance of surviving the long-distance migration due to a number of additional stressors that they face, including temperatures too cold for them to fly and lack of available nectar to fuel their journey.

If temperatures are predicted to stay around or above 55 F, you may consider bringing a few late caterpillars indoors to speed up their development in your warmer house before sending them off on their migratory journey (when at least 55 F, and ideally sunny). Please use best practices for rearing monarchs when bringing caterpillars indoors. Late season observations and rearing (survival) should also be reported to monarch citizen science programs

As milkweed and nectar resources become less available (and temperatures continue to drop), you may be able to bring caterpillars indoors to raise them to adulthood, but the likelihood of those monarchs reaching their overwintering destinations decreases drastically after peak migration. In these cases, you may wish to keep those adults for use in educational programming, or provide them to a local school, educational facility, or youth group for them to observe and learn from. These experiences for youth are highly valuable, and may drive long-term conservation benefits for monarchs. 

How do monarchs orient themselves during migration?

Journey North provides an excellent tutorial on this topic here: http://www.learner.org/jnorth/tm/monarch/sl/38/0.html

What information is available about offshore islands as stopover habitats during migration?

Read more on this topic in an article written by Monarch Watch Conservation Specialist Candy Sarikonda. In addition, there is a Monarch Migration citizen science app that has been developed to help capture these reports and provide additional insight.

Do you have tips for visiting the overwintering colonies in Mexico?

Butterflies begin arriving at the Mexican overwintering sites in early November. By December, all of the butterflies are in residence and have condensed into a smaller area, creating spectacular views. Butterflies roost in these high altitude fir forests through mid-March, with flight activity increasing around mid-February as they prepare for departure. 

Mexico’s monarch sanctuaries straddle two states, the State of Mexico and Michoacán. The Cerro Pelon and Piedra Herrada sanctuaries are located in the State of Mexico, while El Rosario and Sierra Chincua are on the eastern edge of Michoacán state. Mexico City is the closest airport to the sanctuaries, and Zitácuaro, Michoacán, the closest major city. First class buses leave the Observatorio terminal in Mexico City every hour all day long and take two hours to reach the Zitácuaro bus terminal, where taxis are available. While speaking some Spanish is helpful, many manage to make the trip with minimal fluency.

All of the monarch roosts are high altitude, at about 10,000 feet. If altitude sickness is a problem for you, you may want to spend a few days acclimating in Mexico City or the surrounding area before visiting the colonies. Keep in mind that it can get chilly at night in this area and pack accordingly. Seeing monarchs is easier if you have a moderate level of physical fitness, and quite challenging if you have mobility issues. All sanctuary visits involve hiking and/or horseback riding on sometimes steep inclines. That said, about half of all foreign visitors are seniors, and most manage the trip without difficulty.

Cerro Pelon, where the monarch migration was first confirmed, is the least visited and least touristy of the sanctuaries. It features the longest and steepest trail up to the colony, as well as the most pristine forest. El Rosario has been the largest colony in recent years; this sanctuary boasts a paved trail with interpretative signs, and large crowds on the weekends. Sierra Chincua is also one of the more accessible sanctuaries, with a short and attractively paved trail. The location of the Piedra Herrada colony has shifted a lot the past few seasons, meaning that some years the ascent can be steep while others it’s relatively easy. Piedra Herrada’s proximity to Valle de Bravo and Mexico City means that weekends can get crowded here too.

There are many options for accommodations in the area. JM Butterfly B&B, run by a Mexican and American couple, is located in Macheros, a scenic rural village at the entry of Cerro Pelon. The B&B organizes tours to all four sanctuaries, and there is a family-run restaurant next door. In Zitácuaro, there are many budget accommodations located along its main drag, Revolución. A few blocks away, Casa de los Recuerdos has received favorable reviews from travelers. On the outskirts of Zitácuaro, high-end Rancho San Cayetano, run by a European couple, includes a highly praised restaurant and well-tended gardens. Another base for butterfly tourism is the mining town of Angangueo, located half way between the El Rosario and Sierra Chincua sanctuaries. In Angangueo, Hotel Don Gabino and Hotel Don Bruno are the two lodging options.

If you would like to have the details of trip planning and transport taken care of for you, several groups affiliated with non-profits offer organized tours, including Natural Habitat/WWF and Ecolife.

Content in this answer courtesy of JM Butterfly B&B. 

How many generations does the western monarch population see annually?

Typically the western population sees 4 generations, the same as the eastern population. They usually break up from the overwintering sites in California in mid-February and arrive beginning late October.

I thought monarchs were migratory, so why am I seeing monarch caterpillars during the winter?

There is a small non-migratory population of monarchs in southern Florida, but the vast majority of eastern and western monarch populations do undergo a long-distance migration to their overwintering grounds. Overwintering monarchs are typically in a state of reproductive diapause (delayed reproductive maturity) and become reproductive in early spring as they prepare for the return journey to their breeding grounds.

However, some monarchs skip the traditional long-distance migration. In parts of the southern U.S. and California, the year-round persistence of milkweed in good condition, typically the non-native tropical milkweed (Asclepias curassavica), allows monarchs to breed throughout the winter, as indicated by citizen science observations of eggs and larvae during winter months. Scientists don't know exactly what causes monarchs to be reproductive and to forego their long distance migration. It could be exposure to the tropical milkweed, or some other factor, perhaps warmer conditions or even poor physiological condition in the monarchs themselves.

While we don't know why they stay, we do know that year-round tropical milkweed patches, and the year-round breeding that they allow, foster greater transmission of the protozoan Ophryocystis elektroscirrha (OE). Therefore, we recommend that tropical milkweed should be cut back in the winter and fall months in the southern U.S. and California, and should be gradually replaced with native milkweeds as they become available.

Researchers at the University of Georgia, through Project Monarch Health, have been working with citizen science volunteers to document OE trends in monarch populations, with a focus on how winter breeding behavior impacts disease prevalence. For more information on the parasite and how to participate in this research, visit the project website (www.monarchparasites.org). Learn more about the potential risks of growing exotic milkweeds for monarchs on this MJV handout or Expert Q&A

What does overwintering mean, and why do monarchs do it?

Insects have different strategies for surviving the winter. Some only live in places that never experience freezing temperatures, some have evolved to tolerate cold or freezing temperatures in different life stages, and some migrate to escape winter conditions. 'Overwintering' is a term used to describe how something survives the winter.

For monarchs, overwintering means migrating to another location and spending the winter there because they cannot survive the freezing temperatures in the northern parts of their range. Monarchs migrate to the mountains of central Mexico, or the Pacific Coast to overwinter in areas that are warm enough for them to spend the winter without freezing, but cool enough for them to not use all their energy when there isn't much food to eat. Monarchs are in 'reproductive diapause' when they are overwintering, which means they have paused their sexual development and will usually not reproduce until spring. By delaying reproduction and remaining relatively inactive, overwintering monarchs are able to survive up to 9 months. In contrast, breeding adult monarchs in the spring and summer months need plentiful nectar plants to fuel their reproduction, and usually live only about 1 month. For more information on monarch biology, migration and overwintering visit the Journey North and the University of Minnesota Monarch Lab websites:

Monarch Disease and Predators

How can I tell if a butterfly has O.E.?

Unless your vision compares to a microscope, you can't tell with the naked eye whether or not a monarch is infected with O.E. As a caterpillar, the parasite is located within the gut and would be impossible to detect without killing the larvae to obtain a sample of the gut contents. On adult butterflies, O.E. spores are dormant and reside on the outside of the body, usually the butterfly's abdomen. You can't see these dormant spores without observing a sample of the butterflies abdominal scales through a microscope. Learn more about obtaining scale/parasite samples from an adult butterfly by visiting Project Monarch Health, www.monarchparasites.org. Observing these samples through a microscope is the most definitive way of diagnosing O.E., but there are some other symptoms associated with infection by this parasite that we often look for. Heavily infected adults can have trouble emerging from their chrysalis and may fall and thus, can be highly deformed as adults. With heavy infections, you can also see spores under the chrysalis skin before the butterfly has emerged - they appear as small black dots. These symptoms often suggest an O.E. infection, but not always. It is also important to note that not all butterflies that have an O.E. infection will show these symptoms. Some appear to be perfectly healthy to the naked eye, but are still infected with (and possibly spreading) the parasite to their offspring.

How do you check the butterflies for OE infection?

Sampling involves capturing or raising adult monarchs and pressing clear tape against the butterfly's abdomen to collect parasite spores. MonarchHealth is a project in which volunteers sample wild monarch butterflies to help track the spread of this protozoan parasite across North America.

In places where tropical milkweed is native, do monarchs have a high incidence of OE as well?

The short answer is 'sometimes but not always.' The long answer is that monarchs breeding year round on tropical milkweeds in some places like Australia, Hawaii, Bermuda, South Florida do have very high infection rates with OE.  In Hawaii it is very variable - some local sites on some islands have low prevalence and some have nearly 100%.  In Australia it can be variable too. Other locations such as Belize and Costa Rica, where monarchs breed on A. curassavica, are on the lower end of the spectrum with about 20-30% heavy infection rates.  Further research is needed into why this variability exists.

Does OE affect humans or pets?

Luckily, OE only affects a few butterfly species. It does not affect humans in any way and there is no chance that it could adapt to infect humans.  This pathogen is not closely related to any human pathogen and it has only been reported to infect insects.  The spores require a very precise pH shift to activate in larval guts, which our bodies fortunately do not have.  It is a very good question, though, as some insects vector medically important pathogens to humans.

Is it beneficial for OE infected butterflies to live longer? And therefore present a greater risk for infecting other butterflies?

Feeding on highly toxic tropical milkweed allows monarch butterflies that are infected with OE to live longer lives, which is beneficial to the individual butterfly. However, this may not be beneficial from a population level perspective because those individuals may live longer, infecting their offspring and milkweeds, and thus, perpetuating the disease.

Are there natural predators that kill monarch eggs, larvae, and adults?

Yes, learn more about monarch natural predators on the Monarch Lab website. The percentage of monarchs that survive from egg to adulthood is very low. Researchers agree that less than 10% of the eggs that are laid survive to become adult butterflies, and some feel that this number may be significantly under 10%. To account for low survival in the wild, female monarchs can lay 300-500 eggs in their lifetime. 

What should I do if I suspect a monarch I'm raising has OE or some other disease?

Similarly to cold and flu season, disease in monarchs can spread rapidly between individuals. It is rare to find monarch caterpillars in high densities in the wild. Perhaps this is a mechanism to reduce the spread of disease, among other things. Here are a few rules of thumb for how to handle diseased individuals and to make sure that monarchs you bring in from the wild to raise stay healthy (although, disease does happen naturally, so isn't always preventable!): 

  • Never let adults emerge in the same container that caterpillars are eating. Caterpillars cannot spread OE to one another because the OE parasite spores are within the gut of the caterpillar. In the adult butterfly form, however, the spores reside on the outside of the insect's body and drop/rub off onto various surfaces, including the milkweed leaves that caterpillars eat. Once a caterpillar consumes OE spores that dropped off the adult, it becomes infected. Thus, it is always good practice to keep hungry caterpillars in separate containers. 
  • Raise monarchs in individual containers to minimize close contact and spread of disease. It is easier to keep track of and isolate sick or diseased-looking individuals. Viral or bacterial disease in monarchs is extremely detrimental and will spread very quickly to all of the individuals you are raising if appropriate precautions are not followed. 
  • While individual containers help reduce transfer of disease from one container to another, it is important to consider how you are handling them as well. If an individual appears to be sick, handle it last. Wash your hands or change your gloves regularly. Minimize how much you handle adults and larvae; the less you disturb them, the better. It is important to make sure they have fresh milkweed and clean containers, but try to avoid too much handling of the monarch. 
  • Clean your containers regularly with a 20% bleach solution. At a minimum, bleach containers before introducing a new monarch. 
  • When a caterpillar is showing signs that clearly indicate it is sick, it is very rare for the individual to recover. To maintain the health of the others you are raising, separate any sick individuals from others that appear healthy, and in extreme cases, it may be best to euthanize it. 
  • Do not dispose of dead individuals back into your garden to prevent spreading the disease in the wild environment. We recommend freezing dead specimens, and then disposing of them in your trash. 

For more information on rearing responsibly, here is our Rearing Monarchs Responsibly handout!

What are the potential problems associated with planting tropical milkweeds?

Please see the Monarch Joint Venture Fact Sheet and our Q&A with monarch and tropical milkweed experts about the potential risks of growing exotic milkweed for monarchs.

Why are caterpillars disappearing from my milkweed patch?

There are a number of potential reasons for this. If disappearing caterpillars are 5th instar caterpillars, odds are they moved away from your milkweeds to find a safe place to form their chrysalis (they typically do not pupate on milkweed plants). If earlier instars or eggs are disappearing, a more likely culprit is a monarch predator. You can read more about natural enemies on our website. Researchers agree that less than 10% (with some studies as low as 2%) of monarch eggs reach adulthood. 

What is the most appropriate time to cut tropical milkweed back?

It is recommended to prune the milkweed stalks to about 6 inches in height during the fall and winter months to discourage monarchs from establishing winter-breeding colonies. Cutting back the milkweed will also help to eliminate OE spores that may be present on the plant. Re-cut the milkweed every few weeks as leaves re-sprout. Tropical milkweed might pose fewer problems in the northern monarch breeding range because it dies back naturally when it freezes.

These recommendations are not applicable in south Florida (south of Orlando), where a distinctive, non-migratory population of monarchs has long been established. However, native milkweed planting is still encouraged in this area.

For more information on tropical milkweed, read the our handout on the topic.

Population Dynamics

Why are monarchs in southern Florida non-migratory?

A warmer climate and the continuous availability of milkweed (for larvae/breeding) and nectar (for adults) allow monarchs to persist and breed year-round in southern Florida. The extent to which there is interchange between the south Florida population and the eastern population during migration seasons is unknown. 

Is the monarch migration at risk of extinction?

A recent publication indicates substantial probability for “quasi-extinction” of the Eastern monarch butterfly migratory population within 20 years if ambitious habitat restoration and conservation goals are not achieved. Quasi-extinction means that the population reaches levels that are so low that it would be unlikely to recover. To minimize this risk, national population targets have been set to restore the Eastern monarch overwintering population size to 6 hectares of space occupied in Mexico through the addition of habitat across North America, including about 1.5 billion additional milkweed stems. Achieving this population size may help the population rebound more readily after stochastic weather events, such as the major winter storm that occurred in the late winter/early spring 2016 at the overwintering sites in Mexico, which likely caused significant mortality of the butterflies remaining there. Read more here.

Should I purchase monarchs for release?

We do not recommend buying monarchs commercially to raise/release into your garden or other habitat. We feel that creating, restoring, enhancing and maintaining habitat for monarchs and other pollinators is the best conservation strategy. Habitat is beneficial to more than just monarchs, and encourages a healthy ecosystem with diverse pollinators, which are essential to our economy. While monarchs may not always find or utilize every milkweed patch, increasing habitat everywhere helps to ensure connectivity of habitats and increases the likelihood that monarchs will find suitable breeding grounds. Aside from concerns about the purchase and release of commercially raised monarchs, one of the major factors influencing the decline in the first place is broad scale loss of habitat. We must work to restore habitat on the landscape so that the wild population can rebound. 

For more details on concerns expressed by some monarch researchers, view this statement: http://monarchlab.org/biology-and-research/monarch-rearing/captive-breeding-and-releasing-monarchs/. (Note, this statement does not necessarily reflect the views and opinions of all MJV partners).

I thought monarchs were migratory, so why am I seeing monarch caterpillars during the winter?

There is a small non-migratory population of monarchs in southern Florida, but the vast majority of eastern and western monarch populations do undergo a long-distance migration to their overwintering grounds. Overwintering monarchs are typically in a state of reproductive diapause (delayed reproductive maturity) and become reproductive in early spring as they prepare for the return journey to their breeding grounds.

However, some monarchs skip the traditional long-distance migration. In parts of the southern U.S. and California, the year-round persistence of milkweed in good condition, typically the non-native tropical milkweed (Asclepias curassavica), allows monarchs to breed throughout the winter, as indicated by citizen science observations of eggs and larvae during winter months. Scientists don't know exactly what causes monarchs to be reproductive and to forego their long distance migration. It could be exposure to the tropical milkweed, or some other factor, perhaps warmer conditions or even poor physiological condition in the monarchs themselves.

While we don't know why they stay, we do know that year-round tropical milkweed patches, and the year-round breeding that they allow, foster greater transmission of the protozoan Ophryocystis elektroscirrha (OE). Therefore, we recommend that tropical milkweed should be cut back in the winter and fall months in the southern U.S. and California, and should be gradually replaced with native milkweeds as they become available.

Researchers at the University of Georgia, through Project Monarch Health, have been working with citizen science volunteers to document OE trends in monarch populations, with a focus on how winter breeding behavior impacts disease prevalence. For more information on the parasite and how to participate in this research, visit the project website (www.monarchparasites.org). Learn more about the potential risks of growing exotic milkweeds for monarchs on this MJV handout or Expert Q&A

Why are caterpillars disappearing from my milkweed patch?

There are a number of potential reasons for this. If disappearing caterpillars are 5th instar caterpillars, odds are they moved away from your milkweeds to find a safe place to form their chrysalis (they typically do not pupate on milkweed plants). If earlier instars or eggs are disappearing, a more likely culprit is a monarch predator. You can read more about natural enemies on our website. Researchers agree that less than 10% (with some studies as low as 2%) of monarch eggs reach adulthood. 

How do you tell a monarch apart from a viceroy or other mimics?

It is easy to mistake a viceroy or other mimic for a monarch. Viceroy butterflies are commonly mistaken for monarchs. They are slightly smaller in size than monarchs, but their largest distinguishing feature is a thick black horizontal (when wings are open) stripe across both hind wings that is missing from monarchs. If you see that distinct stripe, it's a viceroy! The caterpillars and eggs look very different from immature monarchs. For more information about the differences between viceroys, monarchs, and other mimics, download the Monarch SOS app for Apple devices, or see this detailed description from Journey North.

I don't see many chrysalises, but I do see some caterpillars. Why is this?

You're not alone if you haven't seen many monarch chrysalises in the wild. Monarch caterpillars usually move away from the milkweed plant they were eating when they are ready to pupate, or form their chrysalis. Chrysalises are found on a variety of different plants and structures within the habitat, like benches, windowsills, and other nearby plants or bushes. If you had been seeing large instars and expect they should have transitioned into the chrysalis stage but haven't seen any, don't fret. It is rare to find monarch chyrsalises in the wild, so just because you didn't see them doesn't mean they weren't successful. Keep records about what you are observing through programs like the Monarch Larva Monitoring Project, www.mlmp.org. If you find monarchs one week and the late instars are gone by the next week and you aren't successful in finding their chrysalis, use your knowledge about monarch biology to watch for freshly eclosed (emerged) adult butterflies about 10 days later.

Why is it important that the monarch population is declining? Does the decrease of monarch butterflies have any consequences on any other species?

Conserving the monarch population is important for many reasons, from ecological reasons to educational and inspirational ones. 

First of all, monarchs are pollinators, and need the same habitats (native milkweed and other nectar flowers) as many other pollinators, and even other wildlife. Therefore, if monarchs are in trouble because they don't have enough habitat, then many of our other pollinators and wildlife that share their habitat are in trouble as well. Because they are so well known and their decline is easy to see, monarchs are like the proverbial 'canary in the coal mine' for pollinators. The declining monarch population parallels other declining pollinator populations, which in turn impacts human food systems. Similarly, monarchs and other pollinators are part of a natural food web and ecosystem. Providing enough habitat, like milkweed for monarchs, is essential in maintaining a balanced food web within the ecosystems that are critical in sustaining us.  

Secondly, monarchs have a unique migration which inspires interest in the natural world across the entire continent. The fact that these little insects that weigh no more than a paper clip, travel for thousands of miles to an unknown destination is a phenomenon that deserves protection for it's own sake, but also because it is an amazing way to teach the next generation about science and caring for the environment. If you've ever seen a monarch caterpillar pupate, or an adult emerge from it's chrysalis, you know how amazing their metamorphosis is too, and how excited kids and adults alike can become about it.

In order to reverse the monarch's decline for these important reasons, we need all hands on deck! Find out how you can Get Involved and take action for monarchs today. 
 

Monarch Research

What is known about the potential impacts of mosquito control on monarchs?

The potential impacts of mosquito control on monarchs will vary based on the control method used. A few papers on are available from the University of Minnesota Monarch Lab about non target effects on monarchs from the mosquito control chemicals Permethrin and Resmethrin.

Is the monarch migration at risk of extinction?

A recent publication indicates substantial probability for “quasi-extinction” of the Eastern monarch butterfly migratory population within 20 years if ambitious habitat restoration and conservation goals are not achieved. Quasi-extinction means that the population reaches levels that are so low that it would be unlikely to recover. To minimize this risk, national population targets have been set to restore the Eastern monarch overwintering population size to 6 hectares of space occupied in Mexico through the addition of habitat across North America, including about 1.5 billion additional milkweed stems. Achieving this population size may help the population rebound more readily after stochastic weather events, such as the major winter storm that occurred in the late winter/early spring 2016 at the overwintering sites in Mexico, which likely caused significant mortality of the butterflies remaining there. Read more here.

Should I purchase monarchs for release?

We do not recommend buying monarchs commercially to raise/release into your garden or other habitat. We feel that creating, restoring, enhancing and maintaining habitat for monarchs and other pollinators is the best conservation strategy. Habitat is beneficial to more than just monarchs, and encourages a healthy ecosystem with diverse pollinators, which are essential to our economy. While monarchs may not always find or utilize every milkweed patch, increasing habitat everywhere helps to ensure connectivity of habitats and increases the likelihood that monarchs will find suitable breeding grounds. Aside from concerns about the purchase and release of commercially raised monarchs, one of the major factors influencing the decline in the first place is broad scale loss of habitat. We must work to restore habitat on the landscape so that the wild population can rebound. 

For more details on concerns expressed by some monarch researchers, view this statement: http://monarchlab.org/biology-and-research/monarch-rearing/captive-breeding-and-releasing-monarchs/. (Note, this statement does not necessarily reflect the views and opinions of all MJV partners).