Saving the endangered monarch butterfly from extinction

About the monarch butterfly

The monarch butterfly is known for its white spotted orange-and-black body, whose brightness and contrast are useful in warning off predators of unpleasant taste and possible poison. They span four inches long, weigh less than a gram and are capable of flying up to nine kilometres (6 miles) per hour. 

While it is believed that they were first called the Monarch butterfly in honour of King William III of England - since their colourful bodies matched his nickname The King of Orange - their scientific name, Danaus plexippus, which in Greek means sleepy transformation, refers to the butterfly’s fascinating ability to metamorphose and hibernate. 

During the mating season in the spring and summer, female monarchs lay eggs on the underside of milkweed leaves, which can hatch into larvae or caterpillars and metamorphose into adults in as little as 25 days. Monarch butterfly eggs are as small as 1.2 mm by 0.9 mm and monarch butterfly caterpillars grow to be up to 4.5 cm after feeding on milkweed leaves.

While a female butterfly can lay up to 1,800 eggs in her lifetime, it is estimated that only ten percent of eggs survive and transform into adult butterflies. The monarch butterfly has a lifespan of about five weeks, except for the last generation born each year which lives for up to eight months as they fly to Mexico where they winter.

Where are Monarch Butterflies found? 

Monarch butterflies are native to North America, and their range extends from southern Canada to northern South America. Monarchs are found primarily in open habitats such as prairies, meadows, fields and gardens, and they are particularly associated with milkweed plants, which are the sole host plants for their larvae.

During the summer breeding season, monarchs can be found across their range, with populations concentrated in areas where milkweed is abundant. As the weather cools in the fall, monarchs begin to migrate southward to overwintering sites in Mexico and California. These migrations can cover thousands of miles and are among the most remarkable feats of animal migration in the world.

In addition to their natural range, monarch butterflies have also been introduced to other parts of the world as a result of human activity.

For example, monarchs have been established in Hawaii, Australia, and New Zealand, where they are considered invasive species.

Why are monarch butterflies important? 

In the process of finding nectar for food, monarch butterflies pollinate plants across the Americas, spreading pollen from flower to flower and therefore playing an integral part in sustaining ecosystems.

The threat to pollinators, including butterflies, bees and some bird species, also threaten the health of the ecosystems that they help sustain. 

Critically endangered

How many monarch butterflies are left? 

Since the 1980s, it is estimated that one billion monarch butterflies have been lost, or 97 percent of their population, for which reason they have been labelled as critically endangered.

This worrying trend has continued throughout the past decade: between 2017 and 2018, the Xerces Society estimates that in certain sites, the monarch butterfly population has decreased by 86 percent.

While the true population size is still unknown, in 2018 it was estimated that only about 30,000 butterflies were left. 

Why are monarch butterflies endangered?

• Habitat Loss: Since 1980, the plains and mountains where monarch butterflies once flourished have drastically changed, mostly due to urbanisation and crop changes. This has decreased the amount of area that monarch butterflies have to breed and hibernate, especially as the abundance of the milkweed plant - the only one on which these butterflies lay eggs - has drastically reduced. 
• Illegal logging and deforestation: Monarch butterflies depend on important forests across North America, such as the Monarch Butterfly Biosphere Reserve - a UNESCO world heritage property - outside of Mexico CIty. While the Mexican government has tried to protect these areas and the creatures within them, illegal logging activity has degraded these forest areas in the past three decades, cutting down the Oyamel fir tree on which monarchs hibernate in the winters. 
• Pesticides: Pesticides not only kill off milkweed plants, but also harm the butterflies themselves. Monarchs also fall prey as collateral damage of insecticides intended to kill mosquitoes.  
• GMOS: Genetically modified crops, such as corn and soybeans, are often engineered to be resistant to herbicides, leading to even more destruction of milkweed habitats. To combat this issue, it's important to support sustainable farming practices and advocate for stricter regulations on pesticide use.
• Diseases and Parasites: monarch butterflies are prone to infection by parasites such as flies, wasps, protozoa and bacteria. These parasites tend to infect the butterfly’s larvae, which they use as incubators to propagate. Scientists have discovered that encouraging the health of mycorrhizal fungi around milkweed plants can help monarch butterflies fend off certain parasitic infections, and may be used to bolster conservation efforts. 
• Climate Change: Climate change also poses a threat to the habitats where monarchs breed and spend the winter, such as the forests of oyamel firs in Mexico. This could lead to longer migrations for the butterflies, during which more could perish before reaching a safe haven. Increased variability in temperatures and rainfall may affect the growth and longevity of milkweed, and therefore the monarch’s ability to reproduce and feed. Lastly, the increase in climate change-induced winter storms pose a physical threat to these fragile creatures.

Conservation efforts

Fighting deforestation

To combat the loss of habitats suitable for monarchs, the conservation of forests where they mate, grow and overwinter is critical.

While the Mexican government has taken crucial steps in preserving the forests outside of Mexico City where monarchs travel, these efforts have not been sufficient. In 2020, illegal logging cut down various parts of these forests, causing the butterfly population to plummet by 26 percent.

Working together, North American countries can protect these species by passing stricter regulations that prevent deforestation. 

Butterfly Gardens

The 2,800-mile migratory journey is exhausting and dangerous for butterflies, and many do not make it to their final destination. Butterfly gardens, on the other hand, provide them with areas to stay, breed, feed and rest on their route.

Caretakers of monarch butterfly sanctuaries ensure that there is plenty of milkweed available for monarchs to lay their eggs and keep these groves free of pesticides. 

Planting Milkweed

Communities can help protect monarch butterflies by planting milkweed in their gardens along their migratory routes. Milkweed is highly decorative and easy to incorporate into flower beds.

Gardeners should ensure to plant milkweed that is native to their areas to prevent spreading parasitic infections. It is ideal to plant milkweed in the fall and to plant them in sunny areas, without using pesticides as this will harm the butterflies and their eggs.

Organisations protecting monarchs

• The Xerces Society for Invertebrate Conservation is a nonprofit organisation dedicated to the conservation of invertebrates, including butterflies, and their habitats. The NGO engages in research, education, advocacy and habitat restoration to protect monarch butterflies. It works with landowners, government agencies, and other partners to promote conservation practices that benefit invertebrate species, and provides training and technical assistance to help people protect and restore invertebrate habitats.
• The Monarch Joint Venture (MJV) works with federal and state agencies, nonprofits and communities in the US along the migratory route of monarch butterflies to conserve these creatures and their habitats. It teaches local farms and communities how to plant milkweeds to create healthy habitats for butterflies, among other endeavours.

Image by Kathy Servian