Endangered Species: Monarch Butterfly
The week of May 16th to May 23rd signifies National Endangered Species Week in Colorado, for the 5th time annually. While we believe it’s important to be educated on all endangered species, Thursday, May 20th highlights the possible extinction of the Daughters of the Sun— the monarch butterflies. These creatures are highly spot-able and it’s always a special experience to see one in the wild (who could miss those bright orange colors?? Not to mention their bright coloring is a poison warning to predators). We all know about the great migration of the Monarchs that occurs every year; they travel over 2500 miles from the United States or Canada to the mountains of Mexico to hibernate.
Monarch butterflies have been native to North and South America but have expanded their populations to warmer areas in which milkweed grows. However, after many years, they are no longer found in South America, but instead are split into two separate groups across the Americas: Western Monarchs in the Rocky Mountains and Southern California and the Eastern Monarchs in the Great Plains and Canada. You can also find Monarch butterflies roaming around Hawaii, Australia, New Zealand, Spain and Portugal. There has already been a steady decline in this insect’s community year after year. Monarch butterfly’s population has plummeted 99% in the past year or so. This year, less than 2,000 monarch butterflies were counted, compared to the nearly 30,000 the year before. What is causing this major decline in the Monarch butterfly population? The biggest cause is due to limited amount of usable milkweed, but there are many other factors at play here. Another key factor is deforestation and illegal logging. The effects of this are massive; In 1995, Monarch butterflies habituated over 45 acres (18 hectares) of forest, and that number has dropped significantly to 27 acres in 2003 and now this past year’s count showed less than 5 acres (2.6 hectares) in 2020.
Milkweed is the host plant for Monarch butterflies to lay their eggs on. There are over 100 species of milkweed growing throughout North America, but only about 25% are suitable to be host plants. Swallowworts (a type of milkweed) have similar chemical properties to milkweed in the genus asclepias, that it fools monarchs into laying eggs on them— but the Cynanchum species are not suitable for monarch larvae. When it comes to laying eggs, female monarchs lay between 300 and 500 eggs on the leaves of milkweed over a two-to-five-week period. From there, the only job a caterpillar has is to eat and grow into a beautiful butterfly. Caterpillars only consume milkweed, hence the females laying eggs on this plant. Adult monarchs feed on the nectar but will breed and lay eggs on the milkweed. Milkweed is already vital to a monarch’s life, and to top it off the toxins in milkweed are poisonous and help protect the monarchs from predators. Herbicides and pesticides have been a main cause in the decrease in availability of milkweed to monarchs. Pesticides do more harm than good for the milkweed plant, and the continuous use of this product will hasten the monarch’s extinction.
While Monarch Butterflies are not currently on the endangered species list, countries like the United States and Canada consider Monarchs to be a good candidate for the endangered species list. The population needs to cover over 6 hectares to be considered not in the danger zone, and as we know from this past year’s butterfly count, the Monarch butterfly population has dropped significantly below this threshold. Therefore, Monarchs technically should be considered an endangered species, but little has been done to protect them and their future. It’s been estimated that there’s an 80% probability of the Monarch population will collapse within the next 50 years in the East and 100% probability in the West of extinction of this beautiful species if we don’t take matters into our own hands soon.
It’s time we take matters into our own hands and help save the monarchs. There are many things you can do to prosper this species. The biggest aspect affecting them is the lack of milkweed to lay and grow their populations on. To help this, you can plant your own milkweed and nectar native plants in your own front or backyard. If not milkweed, planting native wildflowers in your garden or other spaces will help rebuild habitats for monarchs and other pollinators; all while setting the foundation to get these butterflies growing back to higher, more normal population level. We all have a job to do to save these beautiful creatures from extinction.
More info on Colorado’s endangered species week: