Do Monarch Butterflies Eat Milkweed? Unveiling the Mystery

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Monarch butterflies are known for their striking orange and black patterns, as well as their remarkable migration journey. An essential part of their life cycle revolves around the milkweed plant. As the sole host plant for monarch butterflies, milkweed plays a crucial role in their survival and reproduction.

Milkweed provides a place for monarchs to lay their eggs and serves as food for the caterpillars once they hatch. The leaves contain cardiac glycosides, making them toxic to most species of birds and mammals, but allowing the monarch larvae to thrive source. With several species of milkweed across different regions, monarchs are known to feed on various kinds source.

Adult monarchs, on the other hand, feed on the nectar of many flowers, including milkweed source. By planting milkweed and other native flowering plants, people can help create valuable habitat for these incredible butterflies to support their life cycle and overall population.

Monarch Butterflies and Milkweed

Life Cycle of Monarch Butterflies

Monarch butterflies have a unique life cycle that heavily involves milkweed plants. It starts with the female monarchs laying their eggs on the milkweed plant. Once the eggs hatch, the caterpillars emerge and start feeding on the milkweed leaves.

During the larval stage, the caterpillars grow rapidly by consuming the milkweed foliage. They then transform into a chrysalis, where they undergo metamorphosis and eventually emerge as adult butterflies. Adult monarchs typically live for 2 to 6 weeks, except for the last generation of the year which can live up to 8 to 9 months ^.

Significance of Milkweed in Monarch Survival

Milkweed is not just a food source for monarchs, it is their sole host plant. The survival of both monarch caterpillars and adult butterflies is directly tied to the availability of milkweed plants.

  • Egg laying: Female monarchs lay their eggs exclusively on milkweed plants as it provides a safe and nutritious environment for the developing larva ^.
  • Caterpillar nutrition: Monarch caterpillars rely solely on milkweed leaves for food, and different species of milkweed are preferred in various regions ^.
  • Toxin consumption: Milkweed leaves contain toxins called cardenolides, which are poisonous to most other animals. Monarchs have developed a resistance to these toxins, and by consuming milkweed, they become unpalatable to predators, thus increasing their chances of survival ^.

Types of Milkweed

Common Milkweed

Common Milkweed (Asclepias syriaca) is a popular native milkweed in North America. It is often the plant of choice for monarch butterflies’ egg-laying*. Some key characteristics include:

  • Large leaves, often fuzzy
  • Pink, fragrant flowers
  • Hardy in various environments

One example is roadside fields where it easily grows.

Swamp Milkweed

Swamp Milkweed (Asclepias incarnata) is another favorite amongst monarchs*. Key features include:

  • Slimmer, smooth leaves
  • Pink or white clusters of flowers
  • Prefers wet habitats

Example: wetlands and areas near water.

Butterfly Weed

Butterfly Weed (Asclepias tuberosa) is a showy milkweed, often grown in gardens. Main traits are:

  • Narrow leaves
  • Bright orange flowers
  • Thrives in well-drained soils

One example is a drought-prone garden.

Tropical Milkweed

Tropical Milkweed (Asclepias curassavica) is not native to North America*. However, it’s sometimes cultivated. Characteristics:

  • Bright red and yellow flowers
  • Glossy, narrow leaves
  • Thrives in warm climates

Example: a south-facing garden in a warmer region.

Milkweed Species Native to NA Preferred by Monarchs Common Color
Common Milkweed Yes Yes Pink
Swamp Milkweed Yes Yes Pink/White
Butterfly Weed Yes No Orange
Tropical Milkweed No No Red/Yellow

Note: Native plants like Common and Swamp Milkweed should be prioritized for monarch habitats.

Planting and Caring for Milkweed

Propagation Methods

There are two primary methods for propagating milkweed:

  1. Seeds: You can collect milkweed seeds from existing plants or purchase from commercial suppliers. Seeds need a three-month period of cold stratification before planting, which can be stored in your refrigerator.
  2. Container plants: Young milkweed plants can be purchased from garden centers or nurseries. Older milkweed plants are challenging to transplant, so starting with young plants is advised.

Garden Tips

To create an ideal milkweed garden for monarch butterflies, consider the following:

  • Choose milkweed species that grow in clumps, such as swamp milkweed (Asclepias incarnata), butterflyweed (Asclepias tuberosa), or whorled milkweed (Asclepias verticillata). These varieties are good choices for perennial beds.
  • Include some common milkweed on the outskirts of your garden to provide additional habitat.
  • Plant milkweed in an area with well-draining soil. Gardeners can add sand to soil to promote drainage if necessary.
  • Space milkweed plants 18 to 24 inches apart to give them room to grow.

Nutrient Requirements

Milkweed plants are relatively low-maintenance when it comes to nutrient requirements. Still, they can benefit from:

  • A well-composted, organic soil, which provides a slow-release of nutrients.
  • Overwintering milkweed plants by allowing them to die back naturally in the fall, which can help return nutrients to the soil.

Comparison of Milkweed Species for Monarch Butterfly Gardens

Species Clumping Habit Perennial Overwintering Ease
Common Milkweed (Asclepias syriaca) No Yes Easy
Swamp Milkweed (Asclepias incarnata) Yes Yes Moderate
Butterflyweed (Asclepias tuberosa) Yes Yes Moderate
Whorled Milkweed (Asclepias verticillata) Yes Yes Moderate

In conclusion, planting and caring for milkweed is a simple process that greatly benefits monarch butterflies. Choosing the right milkweed species, providing proper growing conditions, and understanding their nutrient requirements can help monarchs thrive in your garden.

Other Garden Benefits

Attracting Pollinators

Monarch butterflies, as well as other pollinators, are essential for healthy gardens. They help with pollination, which leads to the production of fruits and seeds. By planting milkweed and other nectar plants, you can attract these beneficial insects to your garden. A few examples of pollinator-friendly flowers include:

  • Milkweed (Asclepias)
  • Coneflowers (Echinacea)
  • Goldenrod (Solidago)
  • Bee Balm (Monarda)

Nectar Plants

Nectar plants provide food for adult monarch butterflies and other pollinators, allowing them to thrive in your garden. By incorporating a variety of nectar plants, you can support numerous pollinators with different preferences. Here is a comparison table of popular nectar plants and their characteristics:

Nectar Plant Bloom Period Pollinator Attraction
Milkweed (Asclepias) Summer to Fall Monarchs, Bees
Coneflowers (Echinacea) Summer to Fall Bees, Butterflies
Goldenrod (Solidago) Late Summer to Fall Bees, Butterflies
Bee Balm (Monarda) Summer to Fall Bees, Butterflies, Hummingbirds

Monarch butterflies use their proboscis to drink nectar from these flowers, which provides them with the energy needed for flight and reproduction. Planting diverse nectar plants ensures a continuous food source throughout the growing season for monarchs and other pollinators.

Monarch Butterfly Migration

Overwintering Sites

Monarch butterflies are known for their remarkable migration journey across North America, traveling from the United States and Canada to their overwintering sites in Mexico (US Forest Service). These overwintering sites provide a suitable habitat for monarchs to survive the colder months. Key features of overwintering sites include:

  • Located in Mexico’s oyamel fir forests
  • Cooler temperatures
  • High altitudes (2,400 – 3,600 meters)

Milkweed Restoration Projects

Milkweed is the sole host plant for monarch butterflies and plays a crucial role in their lifecycle (Penn State Extension). Given the importance of milkweed in the monarchs’ survival, various restoration projects have been initiated to increase the availability of this vital plant. Some benefits of these projects are:

  • Enhanced monarch reproduction
  • Increased food sources for larvae
  • Improvement in overall habitat quality

Examples of restoration projects include efforts by the US Forest Service to plant milkweed in different environments such as fields, roadsides, and urban gardens. This helps to support monarch butterfly populations by providing them with the resources they need during their migration journey.

Here’s a comparison table of common and swamp milkweed species, which are among the preferred milkweeds for monarch butterflies (USDA – ARS):

Milkweed Species Monarch Egg Laying Preference Habitat
Common Milkweed High preference Fields, roadsides
Swamp Milkweed High preference Wet areas

Overall, milkweed restoration projects contribute significantly to sustaining the monarch butterfly population by providing essential resources and habitat throughout their migration across North America.

Protecting Monarch Butterflies

Predators and Threats

Monarch butterflies face various threats, including predators like birds and other animals. These predators tend to avoid Monarchs due to their toxic nature from consuming milkweed.

Common predators:

  • Birds
  • Mammals
  • Insects

Importance of Native Milkweed

Native milkweed, especially common milkweed and swamp milkweed, is crucial for Monarch caterpillars as it serves as their sole host plant.

Benefits of native milkweed:

  • Attracts female Monarchs to lay eggs
  • Provides nutrition for caterpillars
  • Increases Monarch survival rates

In Pennsylvania, butterflyweed is one of the native milkweed species that helps support Monarchs.

Pesticide Awareness

Pesticides can harm Monarch butterflies and milkweed plants. Be cautious when applying these chemicals.

Pesticide pros:

  • Control pests and diseases
  • Promote healthy plant growth

Pesticide cons:

  • Can harm butterflies and other beneficial insects
  • Cause milkweed eradication

To protect Monarchs, implement lower-impact alternatives and prioritize native milkweed species.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Mating Monarch Butterflies

 

mating monarchs
I am SOOO happy to have found your site…I have seen craneflies my whole (long) life and didn’t know what they were….until today, thanks to your site…I recieved my first digital camera abt. a year ago, and haven’t put it down since…what fun!! The mating monarchs were quite high in the tree and these were the best photos I could get…she would keep her wings folded up like the males and then would open them out flat occasionally…what a beautiful site they made…thought I would share this with everyone on your “Bug Love” page…I noticed you haven’t had any recent posts tho’, so maybe you aren’t posting there anymore…anyway, here they are…hope you can use them….thanks for such a wonderful and informative website!
Pat, Hawk Point, MO

Hi Pat,
We have five bug love pages, and we have posted very recently to the fifth page. You must have looked on an older page. You will find your image of mating Monarch Butterflies on our most recent bug love page as well as our most recent butterfly page.

Letter 2 – Mating Monarch Butterflies

 

Monarchs (?) mating
Another one for the bug love pages! I took a series of photos of this mating pair last night in my backyard, just outside of Winnipeg, Manitoba, Canada. They seemed to be enjoying the scotch pine! I am not sure if these are Monarchs, although they don’t seem like any of the other similar species I’ve looked at (Viceroys, Queens). The one with opened wings (the male, I assume) does not have as much black veining as other Monarchs I’ve seen, and the one with closed wings did not have the orange/red colouration on the underside like others I’ve seen. Can you confirm if these are Monarchs, or something else? There are so many in my yard this year.
Elizabeth

Hi Elizabeth,
These are most definitely mating Monarch Butterflies.

Letter 3 – Mating Monarch Butterflies

 

monarch love
Hi Bugman,
I just took these photos of a pair of mating monarchs in Ann Arbor, MI. I looked through the Bug Love pages and didn’t see any monarchs, so I hope these are a useful addition to your site. One question: one of these butterflies has been patrolling my garden for the past week or more, chasing away all the other monarchs until tonight. I’m assuming that’s the male? Just curious.
Martha H.

Hi Martha,
We actually do have other mating Monarch Butterflies buried in the archives of our numerous Bug Love pages, but your beautiful image is still a welcome addition to our site. The behavior you describe is consistant with that of a territorial male butterfly trying to attract a mate. The male Monarch butterfly, like the open winged individual in your photo, can be identified by the conspicuous black scent glands on his lower wings. According to a Monarch website we found: “Males use the pheromones produced by this gland to make themselves attractive to females.” This is a bit of a role reversal among Lepidopterans. Most female moths release pheromones to attract the male, and the male has bushier antennae to better sense the pheromones. In the case of the Monarch, based on your description, we would deduce that the male located a likely food source and staked out the territory. He then released his pheromones and attracted a mate. Thanks for the wonderful account of your observation.

Letter 4 – Mating Monarchs

 

bug love
hello!
I must say I enjoy your site immensely, and love sitting with my son and looking at all the wonderful pictures. I thought you might enjoy this picture of monarch procreation. The evening I took it, I was most thrilled with the colors and the sky and the beautiful way the shot turned out. It was not until I got it home that I realized they were mating! (much to my disappointment and embarassment) I do not share this picture with everyone like I do my other shots, but I couldn’t bear to delete it because it is really beautiful. I do however really appreciate the way these two were modest enough to do their deed behind the cover of their marvelous wings! Have a lovely day,
Ruby K

Hi Ruby,
We are quite happy your reluctance to share your image ended once there was cyberspace between you and the viewer. Just so you know that you are not alone in your fascination with six legged procreation, your image is the 4th Bug Love shot we received today.

Letter 5 – Migrating Monarchs

 

Subject: Monarch Migration
Location: Coryell County, TX
October 20, 2015 1:53 pm
Hello again, the Monarch migration has begun here in central Texas. Just like last year, the butterflies stop to drink water droplets after our sprinkler has watered the lawn.
We need rain badly, although we are not under drought restrictions due to record-setting rains last spring. The weather is otherwise wonderful, 80 degrees and clear, with a light breeze. Here is a link to the current sightings:
http://www.learner.org/jnorth/monarch/fall2015/monarch-butterfly-migration100815.html
The monarchs remind me of fall leaves floating through the air and settling on the grass.
Signature: Ellen

Female Monarch
Female Monarch

He Ellen,
Your female Monarch is lovely.  We hope she visited the milkweed and laid some eggs for you to watch.  Monarchs do have such a lazy way of flying that we often marvel they are able to fly so many miles when they migrate.

Female Monarch
Female Monarch

Letter 6 – Migrating Monarchs

 

Subject: Monarch Migration
Location: Coryell County, TX
October 25, 2016 7:23 pm
Hello, I hope you are both well!
We’ve seen quite a few Monarchs today. I’ve been worried because we haven’t seen very many migrating through this month, but perhaps they are taking a slightly different path this year. The Monarchs are stopping at our Texas Rock Rose, Pavonia lasiopetala, even when the flowers are closing at end-of-day. Weather is warm, 80 degrees, partly cloudy, wind SSW
Here is the link to Journey North website: https://www.learner.org/jnorth/monarch/
Thank you and best wishes!
Signature: Ellen

Monarch
Monarch

Dear Ellen,
Thanks for sending in your wonderful images of a male Monarch.  His scent patches are visible in the flight image.  We were treated to witnessing a Monarch flying past the Washington Monument this past weekend while we were away from the office traveling with Journalism students.

Monarch
Monarch
Male Monarch
Male Monarch

Letter 7 – Milkweed in garden in Ohio attracts Monarch

 

Subject: Monarchs 2016
Location: Columbus, Ohio
June 26, 2016 10:00 am
Hey all at What’s That Bug!! I just had my first Monarch Butterfly sighting of the year. Inspite of my hubby’s comment of “I can’t believe we’re growing weeds in the garden”, my milkweeds are blooming this year, and I just saw my first monarch taking a drink. They seem to be a bit more “flighty” (forgive the pun) than the other butterflies we get, so I’m afraid these aren’t my best pics, but I wanted to let you all know that the Monarchs are in Ohio!
Signature: Amber

Monarch nectaring on Milkweed
Monarch nectaring on Milkweed

Dear Amber,
Thanks so much for providing us documentation of your successful propagation of milkweed and the subsequent attraction of your first Monarch butterfly.  Milkweed is the food plant for the caterpillars of the Monarch butterfly, and the flowers are a rich source of nectar for many butterflies, making milkweed an excellent addition to any butterfly garden.  We just returned from a trip to Youngstown, Ohio, on the Pennsylvania border, and we were struck at the dearth of milkweed on roadsides.  Many years ago, milkweed was quite common, but as farming techniques became more efficient, and as more open space was cleared to rear crops, milkweed populations have diminished, leading to decreased populations of Monarch butterflies as well.  Your individual is a male, as evidenced by the black spots on the hind wings.  See the Arizona State University Ask a Biologist page for a visual difference between male and female Monarch.  Hopefully, female Monarchs will also visit your milkweed and lay eggs.

Letter 8 – Monarch

 

Monarch or Viceroy?
Can you tell me what kind of butterfly this is? It looks like it might be a Monarch or Viceroy. Picture taken in New Jersey.
Steve

Hi Steve,
This is a Monarch. The wings are shaped differently and there is no black bar on the hind wings.

Letter 9 – Monarch

 

Monarch?
Location: Jacksonville FL
January 23, 2012 10:01 am
Found this one in an enclosed patio. After photographing, I set it free.
Very pretty!
Sorry for the screen being in the way of the under shot.
Signature: Danno

Monarch

Dear Danno,
You are absolutely correct.  Furthermore, your Monarch is a female.  The sexes can be distinguished by a the scent scale patches on the lower wings of the male, which appear as a dark spot on the black vein close to the body which is visible in the lower butterfly in this mating pair of Monarchs from our archive.  The Monarch is also known as a Milkweed Butterfly.  Monarchs are famous for their seasonal migrations and places like Pismo Beachhave turned Monarch roosting locations into tourist attractions.

Monarch

Letter 10 – Monarch

 

Need help identifying Butterfly
Location: South Central Wisconsin
March 2, 2012 11:04 am
Hello, I run a garden at my local(southern Wisconsin) elementary school and took this shot in September. The butterfly is perched on one of the sunflowers the students plant every spring during the last week of school. Our garden is right next to a restored prairie that’s a registered Monarch way station. My good friend (and long time WTB fan!) CZ recommended I submit for your expert analysis. Is it true that Monarchs feed only on milkweed? The butterfly appears to be feeding on the sunflower. Thanks for your help!
Signature: KB

Monarch

Dear KB,
While it is true that the Monarch Caterpillar feeds exclusively on milkweed, the adult Monarch butterflies are not particular about the flower they take nectar from, though milkweed flowers are one of their favorites.  This is indeed a Monarch butterfly.

Dear Daniel,
Thank you so much for your help!
Kind regards,
Kris

Letter 11 – Monarch

 

Subject: Daniel – Monarch Butterfly Sighting
Location: Hawthorne, California
May 8, 2013 6:04 pm
Here is our first sighting of a Monarch Butterfly in the back this Spring. She spent a short time feeding on the Mexican Milkweed and there was a bit of ovipositing involved. Don’tcha love this time of year?
Signature: Thanks, Anna Carreon

Monarch
Monarch

Hi Anna,
We haven’t seen a Monarch yet this spring, but the Painted Ladies and Mourning Cloaks have been about and the Swallowtails appeared earlier than usual this spring.  No Anise Swallowtails yet, but we have seen a Western Tiger Swallowtail flying around the yard.

Letter 12 – Monarch

 

Subject:  Monarch Butterfly
Location:  Kings Canyon, California
July 30, 2014
hi, what’s that bug? i know you have many photos of this butterfly, but how do i tell if this is a male or female? photo taken in king’s canyon national park on july 17th, 2014. thanks! clare.

Monarch Butterfly
Monarch Butterfly

Hi Clare,
This is a female Monarch, and she can be distinguished from the male Monarch by the lack of a “scent patch” on the hind wings of the female.  According to BugGuide:  “Males have scent-scale patches on hindwings, prominent when wings are open, and just possible to see when wings are folded.”  In this image of mating Monarchs, the male is the lower butterfly with the open wings.  Though we have been hearing and reading many accounts of the drop in populations of Monarch butterflies in recent years, probably due to habitat loss, but also rumored to be connected to GMO corn pollen (not substantiated), we have been noticing numerous migrating Monarchs in Mount Washington in recent weeks.  Perhaps this is connected to the cultivation of milkweed in eco-friendly gardens, perhaps the migration patterns are changing, or perhaps we have just been more observant.  When we cropped your image, we removed an out of focus Greater Fritillary on the right to concentrate more on the Monarch, but it seems your meadow made butterfly viewing quite a marvelous experience.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Monarch Butterfly

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