Monarch Butterflies

by Surleen Kaur

Order: Lepidoptera (butterflies and moths)

Family: Nymphalidae (brush-footed butterflies)

Species Name: Danaus plexippus (monarch butterflies)

How to identify:

As with most insects, monarch butterflies have six legs and four wings. Monarch butterflies have striking deep orange wings (~ five inches wingspan) with black lines and white dots on the borders. The depth of the orange color and the size of the white spots vary; both of these are correlated with migration success (Davis et al., 2012; Davis et al., 2023). 

Advanced ID: The Nymphalidae butterfly family is recognized for its substantial size and unique brownish hue, frequently decorated with black markings. Their hind wings are characterized by an adequately developed vein that intersects other veins, resulting in closed discal cells while the antennae lack scales. One of the most crucial features that distinguish them from other butterfly families is the presence of a distinct marking known as 3a in the forewing. (Otaki, 2020.

Ecology

Metamorphosis Type: Complete metamorphosis – egg, larva, pupa, adult. Larvae often look very different from adults (e.g., caterpillar and butterfly, maggot and fly)

Geographic Range: The Monarch Butterfly ranges from southern Canada to Mexico, excluding some areas of the Pacific Northwest and Alaska. Western migrating populations overwinter in coastal California, and migrating populations east of the Rocky Mountains overwinter in central Mexico (Malcolm, 2018).

Habitat: In the summer, monarch butterflies typically live in prairies, meadows, and grasslands. They find shelter in milkweed plants, which also serve as a food source for them. During the winter months, they prefer to roost in forests (“U.S. Forest Service,” n.d.).

Trophic Level: The monarch butterfly is classified as a primary consumer due to its diet which primarily consists of plants. As a primary consumer, it plays an important role in the food chain by converting the energy from plants into a form that can be used by other organisms. This makes it a vital component of many ecosystems where it is found (Doug Tallamy,2023).

Food: Monarch caterpillars are specialists in milkweeds; this is their only food. They use their strong mandibles to chew the leaves of the milkweed plant. Monarch adults have a long, tube-like proboscis to gather nectar from flower species. (National Wildlife Federation n.d.).

Why should we care?

Human Uses: While Monarchs may not be the most effective pollinators, they do contribute to the pollination of certain plant species. They are widely recognized as a symbol of the importance of pollinators in maintaining healthy ecosystems and food production. Monarchs are also known as a flagship species, meaning that their conservation can benefit many other species in their habitat. Their striking appearance and migratory behavior make them a popular and beloved insect among people all around the world. (Monarch Joint Venture.n.d.)

Pollination: Milkweeds are not solely pollinated by monarch butterflies. Although monarchs are important pollinators for milkweed, other insects such as bees, wasps, and flies can also pollinate the flowers. Some milkweed species have evolved to attract specific pollinators, which exclusively feed on milkweed and pollinate the flowers while doing so. (Monarch Joint Venture.n.d.)

Conservation: The monarch butterflies face several threats, such as the loss of milkweed resources because of genetically modified pesticides, crops, and fertilizers, which led them to be listed as a vulnerable species in 2023 (IUCN, 2023) The migratory subspecies have certain adaptations that allow them to undertake this journey, such as being able to store fat reserves and fly at high altitudes to take advantage of favorable winds. In contrast, non-migratory subspecies of Monarch butterflies remain in the same general area year-round and do not undertake long-distance journeys like their migratory counterparts (Malcolm, 2018).  

How we can help:

1. 1. Plant a pollinator garden using native plants. Even a small garden can make a big difference- including in urban areas!  Use this website and this Urban Habitat Assessment tool to get started.  Arrange your plants in clusters (rather than individual plants separated throughout the garden). Many species are active in the fall, so include plants that flower throughout the season (NJ Division of Fish, Game, and Wildlife, n.d.). Monarchs specifically need milkweed for the larval stage. Plant natives, like common milkweed (Asclepias syriaca), swamp milkweed (A. incarnata), or butterfly weed (A. tuberosa). Do not plant tropical milkweed (A. curassavica), because this non-native plant lowers migration success and even causes the Monarchs to stop migrating (Wheeler, 2018).
   2. Provide a puddling station for butterflies; a simple version is a saucer filled with moist sand or soil; then add a small amount of composted materials or overripe fruit as a nutrient source (Florida Wildlife Federation, 2020). 
   3. Avoid pesticides in your own garden (Xerces Society, n.d.), and purchase more organic foods to support organic farmers. 
   4. Sign the Pollinator Protection Pledge and / or add your garden to the Homegrown National Park, and put up a sign to let others know.

Did you know?

• Milkweeds (Asclepias spp.) produce chemicals called cardiac glycosides that are toxic to many animals. Monarch caterpillars eat the milkweeds and store the toxins. Predators learn to avoid eating monarch butterflies because they are distasteful and may induce vomiting (“U.S. Forest Service” n.d.).
• Viceroy butterflies (Limenitis archippus) look similar to monarchs. For a long time, this was thought to be Batesian mimicry (where one species is unpalatable, and the palatable species mimics it), but recent evidence demonstrates that this is a case of Müllerian mimicry, where both species are unpalatable to predators. (North Dakota Game and Fish. n.d.).

Images Cited

Photo 1: Henry T.Mclin. 2014. Licensed under Creative Commons License | Link

Photo 2: James Lusher. 2005. Licensed under Creative Commons License | Link

Photo 3: Terry Donavan. 2023. Licensed under Creative Commons License | Link

Photo 4: Vicki Deloach. 2019. Licensed under Creative Commons License | Link

Photo 5: Anita Gould. 2011. Licensed under Creative Commons License | Link

Photo 6: Anita Gould. 2011. Licensed under Creative Commons License | Link

Photo 7: O’Hearn-Kickham. 2006. Licensed under Creative Commons License | Link

Photo 8: Sid Mosell. 2010. Licensed under Creative Commons License | Link

Photo 9: Peter Miller. 2015. Licensed under Creative Commons License | Link

Photo 10: Aquamarine. 2018. Licensed under Creative Commons License | Link

Photo 11: Dean Morley. 2013. Licensed under Creative Commons License | Link

Photo 12: David Marvin. 2018. Licensed under Creative Commons License | Link 

Photo 13: Vicki Deloach. 2012. Licensed under Creative Commons License | Link

Photo 14: Gordon Ott. 2013. Licensed under Creative Commons License | Link 

Top