The Monarch butterfly (Danaus plexippus) is native to North America, from Central America northwards to southern Canada, and from the Atlantic to the Pacific coasts.
Three geographically distinct populations make up the total North American range of the species, one each both east and west of the Rocky Mountains, and one Central American.
Each of these populations has a distinct migratory pattern. Monarchs that live west of the Rocky Mountains will migrate to southern California for winter while monarchs that live east of the Rockies will migrate to Mexico.
This insect is the most widely recognized of all American butterflies with its distinct orange, black, and white wings.
Some argue that Monarch butterflies are the most beautiful of all butterflies. They are considered the “king” of the butterflies, hence the name “monarch”.
One of the most notable characteristics about the monarch is the astonishing 3000-mile journey some will make in the fall to their wintering grounds in the Sierra Nevada Mountains of Mexico or to southern California, depending on which part of the United States or Canada they migrate.
Monarchs can travel between 50 – 100 miles a day; it can take up to two months to complete their journey to winter habitats. Millions of Monarch butterflies make the trip down to Mexico to roost for the winter. During the migration, tens of thousands will land on a single tree in certain areas along their migratory path.
The Monarch Life Cycle is called metamorphosis. This is the series of developmental stages that insects go through to become adults.
Butterflies and moths have four stages of life: egg, larva (the caterpillar stage), pupa (the chrysalis phase in a butterfly’s development),
Light, temperature, and humidity all play an important role in determining how long it will take a Monarch to complete its life cycle.
Warmer temperatures (so long as it’s not too warm), higher humidity (so long as it’s not too humid), and extra light (so long as it’s not too much light) generally aid in faster development.
Developing Monarchs usually prefer a temp of 70 to 80 degrees, humidity of 60% to 70%, and normal summer daylight/night patterns.
The Monarch butterfly’s life cycle is the egg, the larvae (caterpillar), the pupa (chrysalis), and the adult butterfly. The four generations are actually four different butterflies going through these four stages during one year until it is time to start over again with stage one and generation one.
In February and March, the final generation of hibernating Monarch butterflies comes out of hibernation to find a mate.
They then migrate north and east in order to find a place to lay their eggs. This starts stage one and generation one of the new
In March and April, the eggs are laid on milkweed plants. They hatch into baby caterpillars, also called the larvae. It takes about four days for the eggs to hatch. Then the baby caterpillar doesn’t do much more than eating the milkweed in order to grow.
After about two weeks, the caterpillar will be fully-grown and find a place to attach itself so that it can start the process of metamorphosis. It will attach itself to a stem or a leaf using silk and transform into a chrysalis.
Although from the outside, the 10 days of the chrysalis phase seems to be a time when nothing is happening, it is really a time of rapid change.
Within the chrysalis the old body parts of the caterpillar are undergoing a remarkable transformation, called metamorphosis, to become the beautiful parts that make up the butterfly that will emerge.
The Monarch butterfly will emerge from the pupa and fly away, feeding on flowers and just enjoying the short life it has left, which is only about two to six weeks. This first generation Monarch butterfly will then die after laying eggs for generation number two.
The fourth generation of Monarch butterflies is a little bit different than the first three generations. The fourth generation is born in September and October and goes through exactly the same process as the first, second and third generations except for one part.
The fourth generation of monarch butterflies does not die after two to six weeks. Instead, this generation of Monarch butterflies migrates
Monarchs can produce four generations during one summer. The first three generations will have life spans from 2 – 6 weeks and will continue moving north.
During this time they will mate and have the next generation that will continue the northward migration. The fourth generation is different and can live up to nine months. These are the butterflies that will migrate south for winter to either Mexico or southern California.
In their larval stage monarch caterpillars feed almost exclusively on milkweed and as adults get their nutrients from the nectar of flowers. The M
The milkweed they feed on as a caterpillar is actually a poisonous toxin and is stored in their bodies.
This is what makes the Monarch butterfly taste so terrible to predators. Wherever there is milkweed there will be Monarch butterflies.
According to the U.S. Fish and Wildlife Service. Even so, the last two winters scientists recorded the lowest number of Monarchs there since annual surveys began 20 years ago.
Monarch numbers have dropped in tandem with rising use of glyphosate, an herbicide introduced in 1997 that kills plants without a genetically engineered immunity. This includes milkweed, the only food a Monarch caterpillar eats.
Clusters of Monarchs covered 45 acres of their Mexican wintering grounds in 1996, but now their clusters make up less than two acres. It is predicted that one of the many effects of climate change will be wetter and colder winters.
If they are dry, Monarchs can survive below freezing temperatures, but if they get wet and the temperature drops they will freeze to death.
Because hundreds of millions of Monarchs are located in such a small area in the Sierra Nevada of Mexico during the winter, a cold snap there could be devastating.
IUCN has designated the Monarch migration a threatened phenomenon.
In 1986, the Mexican government created the Monarch Butterfly Biosphere Reserve which protects 62 square miles of forests in the Sierra Madres where hundreds of millions of monarchs spend each winter. The Biosphere Reserve was expanded to include 217 square miles in 2000. Local organizations are also working to stop the illegal harvesting of trees on the reserve to protect wintering habitat.
Other threats to the M
Monarch butterflies cannot fly if their body temperature is less than 86 degrees. They will sit in the sun or “shiver” their wings to warm up
This means the Monarchs may be forced to adapt and produce another generation to reach further north. It is uncertain whether they will be able to do so. Therefore, few Monarchs may be able to make the extended trip back to Mexico for winter.