Monarch butterfly

Update of part of post from November 30, 2013

Since next week is Thanksgiving, I’ll be taking a break from Next Door Zoo to let you spend more time with family and friends. Be sure to come back on December 3, for more amazing animal facts!

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The monarch butterfly is a relatively common insect living mostly in the Americas. In case you haven’t noticed, I have been re-doing some of my previous posts to include more information. At this point three years ago, I did a post about both the monarch and viceroy butterflies. Since my articles are so much longer than they were then, I decided to split that article into two articles. I will tell you about the monarch this week and the viceroy in the next article.

Anyway, on to what you really want to read. Monarch butterflies are mostly orange with black webbing. They also have a lot of small, white speckles around the outside of their wings. Their bodies, however, are completely black. One interesting fact about the webbings on these butterflies is that they are symmetrical. The webbings on the left wings are a mirror image of the webbings on the right wings.

Male and female monarchs look slightly different from each other. The picture above shows a female, while the one shown below is a male. One of the differences is in the black webbing. The webbing on females is thicker than on the males. The easiest way to distinguish males and females is the small black spot on the webbing that males have on the lower parts of their wings.

Monarch butterflies are rather common, and because of that, they have gotten several distinctions. They are the state insect of Alabama, Idaho, Illinois, Minnesota, and Texas. They are also the state butterfly of Vermont and West Virginia.

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Monarch or Viceroy?

Monarch and viceroy butterflies are very similar, but there are a few ways to tell them apart. One difference is that the viceroy, shown on the left, has a curved, black line in the webbing going across both of the lower parts of the wing. The monarch does not have this line. Viceroy butterflies are also slightly smaller.

They also fly differently than each other. Viceroys have a faster, more erratic flight, while monarchs are slower and have an almost floating flight. Viceroys also do not migrate, while monarchs, as we will see later, have a very special migration.

As I already mentioned, my next article will be about the viceroy, but since I already talked about there differences here, I will not talk about the same thing again then.

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Size

As I just said, monarch butterflies are larger than viceroys, and they are also probably larger than you would think. They have a wingspan that is between 3.4 and 4.9 inches (8.6 to 12.4 cm) long. Normally they are closer to the middle of this range, averaging a little less than 4 inches (10 cm).

As with most insects, especially butterflies, monarchs are extremely light weight. They weigh between 0.27 and 0.75 grams. I often compare animals’ weights to common items, but these butterflies are so light that I couldn’t find anything that weighs exactly their weight! Some examples of this that weigh one gram – which is about twice this insect’s weight – are a paperclip, a pen cap, or a stick of gum.

Diet

Monarch butterflies are just like most other butterflies when it comes to their diet as adults. They consume, (you can’t really say they eat it), nectar from flowers. Nectar is extremely sweet and is made up of about 20% sugar! I think if one fifth of what I ate was sugar, I would be able to fly too!

The monarch caterpillars, however, have a different diet than most other animals like them. They eat almost exclusively the milkweed plant, and this helps them out. These plants have certain toxins in them, that, while harmless to the young monarchs, are dangerous to predators. They can even cause vomiting in birds that happen to eat one!

Habitat and range

Although monarch butterflies are most known for living in North America, they have a much larger range. They also inhabit most of South America, as well as places in Australia, New Zealand, and many pacific islands. The map below shows more exactly what this animal’s range is.

It may not be exactly right, though, as some sources show the monarch inhabits most, if not all, of South America instead of just the northern part. The area in the Pacific ocean that is light orange does not mean that these butterflies live in the ocean. Instead, it represents the hundreds of tiny islands that monarch butterflies call home.

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As I mentioned in the last section, milkweed is a very important part of young monarchs’ diets. Because of this, monarch butterflies only live in areas where this plant is common. Such habitats include fields, meadows, marshes, and roadsides. They may sometimes be found in forested areas, but since milkweed is not as common there, it is less likely to find a monarch butterfly there.

Status and threats

Despite how well-known these animals are, they have not yet been classified by any major conservation association. However, given how common they are, I would guess that monarch butterflies are of least concern.

The diet of the caterpillars, which I talked about earlier, makes them toxic to predators for the rest of their lives, so many predators heed the bright orange warning colors and refuse to eat what could be an easy snack in a monarch butterfly. Some animals are immune to these toxins, so they can prey on these butterflies with no negative side-effects. These potential predators include wasps and spiders.

Since milkweed is such an important part of the monarch’s life, when milkweed plants are destroyed by agriculture or construction, this butterfly suffers as well. Pesticides meant to kill insects that eat crops may harm monarchs that are just pollinating the crops. Habitat loss and parasites are two more threats these creatures face.

Migration

In the United States, butterflies are normally thought of as summertime animals. For the monarch, this is because they migrate for the winter. When the weather starts getting cooler, these butterflies start flying down to Mexico. They sometimes fly up to 3,000 miles (4,828 km) just to get there! This is a long trip for a fragile animal like a butterfly, but they are surprisingly endurant. They have been known to travel up to 100 miles (161 km) in a single day! And you thought a marathon was long!

They don’t always travel this long in one day, so just a one way trip to Mexico can take them as long as two months. While in Mexico, thousands or millions of monarch butterflies cluster together on trees to bask in the sun and stay warm.

Reproduction and young

Once spring has arrived, the monarchs prepare to leave their winter homes. Before they do that, however, they mate. On their way back to their summer homes, the females lay eggs. Since milkweed is such an important part of a monarch caterpillar’s diet, the mothers help their young to find this plant more easily by laying their eggs on milkweed.

After about four days, the eggs hatch, and the caterpillars that come out eat almost constantly. They increase their size by almost 2,000 times over the next two weeks! After this time has passed, the young monarchs form a chrysalis. They stay in this hard covering for between 9 and 15 days while they undergo metamorphosis. Below is a picture a monarch caterpillar (left) and a monarch chrysalis (right).

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After they emerge from the chrysalis, the butterflies still do not look like the ones in the pictures I showed at the top. Instead, their wings are crumpled up. This does not last long, though, and the butterfly will bask in the sun and flap its wings so they can expand and harden.

These butterflies that are born in the spring or early summer will not make it to the fall. Instead, they lay eggs and start the process over again. This happens multiple times in the same summer. By the time the butterflies need to migrate again, the ones making the trip are the great-grandchildren of the ones that made the trip just one year ago! This means that three generations pass in just one summer!

Since I already told you what the next animal is, I don’t have its picture down here. Don’t forget to come back in two weeks to read about the viceroy butterfly!

Sources:

Photo credits:

  • Monarch butterfly – Kenneth Dwain Harrelson
  • Male monarch butterfly – Derek Ramsey
  • Monarch and Viceroy – D. Gordon E. Robertson and Kenneth Dwain Harrelson
  • Monarch butterfly range –  Harald Süpfle
  • Monarch caterpillar – Public Domain
  • Monarch chrysalis –  Armon

One Response

  1. Viceroy butterfly
    Viceroy butterfly at |

    […] weeks ago. If you missed that, or you want to read it again, you can learn about their differences here under the second […]

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