Monarch butterflies

Who doesn't get excited when you see the first monarch butterfly in spring?

Here you will find all you need to know and more about these beautiful insects.

Information boxes: colour coded depending on the age of the viewer
Printable lifecycles, worksheets and word puzzles (more will be added soon...)
Photo galleries: There are two photo galleries on another page. One follows the daily life of a caterpillar to adulthood. The other has additional photos of the caterpillars/butterflies. All photos and videos on this page were taken by Ms Lun.

Information in light blue boxes is the basic version.

Year level: 1-3 Curriculum level: 1-2

Information in orange boxes has more detail, suitable for

Year level: 3-6 Curriculum level:1-3

Information in pink boxes has extra information, suitable for

Year level: 7+ Curriculum level:3+

Printable stuff

Answers to Word Finds...

Printable life cycles

There are two versions, one a little simpler (just print the one you want)

Printable worksheet: Easy

Contains a word search (10 easy words in lowercase) and a basic lifecycle to label

Word Find: Medium Yr 4-6

This word search has 20 words, upper case .

Word Find: Hard Yr 7+

This word search has 30 words, upper case .

Monarch butterfly facts

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Lepidoptera

Family: Nymphalidae

Genus: Danaus

Species: D. plexippus

Host plant

Danaus plexippus feed almost exclusively on the swan plant (Asclepias species). It is considered native to NZ but also found in North America. The swan plant is a type of milkweed and it produces a white sap that can be poisonous or irritating to some insects and animals.

Swan plant flowers and immature seed pods (also called follicles).

The mature follicles split open to reveal hundreds of seeds that are attached to white, silky filaments called coma or floss.

Monarch butterfly life cycle (simplified)

Pupa

In the green chrysalis, the pupa changes over the next 10 to 14 days. When the chrysalis darkens the butterfly is nearly ready to emerge.

life-cycle-of-a-monarch-butterfly-simple

Adult

Butterflies can live for 60 to 70 days. Males have a spot on each hindwing (see picture in the orange box "Butterfly" section below).

Egg

Hatch after 4 to 8 days. They are white but get darker closer to hatching.

Caterpillar (or larva)

The tiny caterpillar eats and eats. After 2-3 weeks, it will be about 5.5 cm long.

Monarch butterfly life cycle:

each stage covered in more detail

Egg

A single female can lay about 40 eggs in one day.

The eggs are whitish-yellow but darken closer to hatching (this is the head of the developing larva).

Hatching (eclosion)

Eggs hatch after 4-8 days (temperature dependent). The larva eats its way out of the egg. This can take about an hour (see video). It will often eat the rest of the egg once it has hatched.

Creamy white egg.

The head of a caterpillar eating its way out of the egg.

Darkening egg.

The hard, outer layer of the egg is called the chorion. A layer of wax prevents the egg from drying out. There are also raised ridges on the outside of the egg.

A newly hatched caterpillar eating the remainder of the egg.

Caterpillar or larva

The caterpillar is an eating machine! Over the next 2-3 weeks, it will grow to about 5.5 cm long.

During this time, the caterpillar has to moult or shed its skin or exoskeleton 3 times. The first time is when the caterpillar is about 3 days old. It anchors its rear legs to the surface it is on and "walks" out of its old skin. If you see a caterpillar in the same place for a day (and doesn't eat), chances are, it is preparing to moult. The caterpillar will often eat the skin it has shed.

The stage between each moult is called an instar.

In 2 minutes, a new exoskeleton is revealed

Here's the shed skin

A newly moulted caterpillar.

Some insects use camouflage to avoid predators. The monarch has bright colours to warn off predators. This is called aposetism.

The monarch caterpillar obtains toxins from the swan plant that make it poisonous to predators.

Caterpillar or larva

The head of the larva has:

a pair of short antennae (help guide the larva)
mouthparts (upper lip, mandibles and lower lip)
6 pairs of ocelli (simple eyes), but it is quite blind
maxillary palps - sensory organs that direct food into the larva's jaws

Image from monarchwatch.org

The spinneret is the silk-spinning organ of a spider or the larva of butterflies and moths. In a caterpillar, it is located on the underside of the head (on a spider it is located at the rear of the abdomen). The silk is produced in the silk glands as a liquid. When it makes contact with air, it hardens forming a solid strand.

Silk is used as an escape or safety mechanism, especially for little caterpillars, and in the pre-pupa stage to make the silk mat.

The thorax of the larva has:

3 pairs of true legs (or jointed legs). These become the legs of the butterfly.

The abdomen of the larva has:

5 pairs of prolegs (or false legs). They have tiny hooks called crochets on them that help the larva hold onto the silk mat or leaf

Image from monarchwatch.org

The thorax and abdomen of the larva also has tiny breathing holes called spiracles (external respiratory or breathing opening found in insects). Insects don't have lungs so they get oxygen through the spiracles which are connected to trachaea (long rubes that deliver oxygen around the body).

Inside the caterpillar

The larva has several internal organs:

brain connected to a ventral nervous system. Ventral means it runs down the stomach (underside) of the caterpillar
silk glands
heart which pumps hemolymph (blood) around the body
digestive system: (fore, mid and hind parts). The mid section is where the digestive enzymes are produced.
Malpighian tubules: remove waste products
fat body: the storage organ for nutrients

Image modified from animal.howthingswork.org

The Latin word larva means 'ghost' or 'mask'.

Pre-pupa stage & chrysalis formation

After 2-3 weeks of eating (again temperature dependent), the caterpillar will be ready to form a chrysalis. It will find a sheltered place, away from other hungry caterpillars. It attaches its rear legs to the surface by creating a silk mat. Then it hangs upside down in a "J" shape for about 24 hours. Next, the caterpillar wriggles and sheds its skin for the 4th time to reveal a soft green chrysalis. Gradually, the chrysalis hardens.

After hanging upside down in a J shape, the larva straightens, the the skin splits at the back of the head and the skin is completely shed. The soft new exoskeleton is revealed. Over the next hour, the chrysalis will harden.

Silk is composed of two proteins:

Fibroin: the inner structural protein (about 80%)

Sericin: the sticky, outer coating

As the larva sheds the exoskeleton and wriggles, it is pushing the black cremaster (the appendage between the chrysalis and the silk mat) firmly into the silk mat. The shed skin falls off.

Pupa stage

The pupa undergoes metamorphosis over the next 10-14 days. As the butterfly is taking shape, the chrysalis changes colour to a darker green, then to black. You will be able to see the wing pattern in the developing pupa.

One hour post-moult, wings are visible

The chrysalis is pale green and the orange wings are visible

The chrysalis becomes more transparent and the wings are more developed

Very dark, will

eclose very soon

Metamorphosis is a Greek word meaning transformation. As the butterfly takes form, the chrysalis becomes transparent.

Pupa or

chrysalis

Pupa comes from the Latin word meaning 'doll' or 'girl'.

Chrysalis comes from a Greek word khrusos meaning ‘gold’. Some scientists theorise that because the spots aren't real gold, they are cells that reflect light as a metal would do.

As the butterfly takes form, the chrysalis becomes transparent.

This 1m30 video shows a butterfly eclosing from a chrysalis.

Butterfly

The final moult (also called eclosion) reveals the butterfly. In less than 2 minutes, the butterfly emerges with a large abdomen and crumpled up wings. Did you notice it eclosed upside down? Can you think why this is?

Over the next few hours, the butterfly pumps fluid from the abdomen into the wings. The wings are still delicate and the butterfly cannot fly. It takes a few hours before the butterfly is ready to fly. It will also excrete waste products (thicker, reddish at first then a clear, water-like substance).

Did you know male and female butterflies look different?

Just look at the wings...

A male butterfly. The hind wings have a dot on them

A female butterfly. The veins on the wings are thicker (and no dots on hind wings)

The chrysalis splits and the butterfly pushes its way out of the chrysalis

From the fat body and crumpled up wings when it first emerged to 10 minutes later when the wings are full size. However, it will take a few hours before the wings are strong enough for flight.

Right: a female butterfly laying an egg on an immature swan plant seed pod.

Do the males dots have a function?

The raised dots are scent pouches. The males release pheromones (chemicals) to attract a female monarch butterfly. Within the scent pouch are specialised scales called androconia or "male dust". (From Latin andro = man and Greek konis = dust.)

Adult butterfly

The head of the butterfly has:

a pair of antennae. These are the main olfactory (smell) organs and are covered with over a million olfactory scales, hairs or pits.
proboscis: this is a coiled feeding tube that extends to allow the butterfly to suck nectar from flowers.
ocelli (simple eyes)
palps - sensory organs near the mouth involved in touch and taste
compound eyes - unlike the caterpillar, monarch butterflies have good vision.

Learn about compound eyes

The thorax has 6 legs. Monarchs look like they only have 4 because the first pair are tucked up close to their body. Each leg has 6 joints and butterfly feet are called tarsi.

???Did you know???

Monarch butterflies taste with their feet!!

Over-wintering

Butterflies that eclose in late autumn will migrate to over-wintering sites to try to survive the winter. Clusters of butterflies huddle together to keep warm. They can slow down their body functions (also called diapause). They will only leave to find food (nectar). These butterflies may live for 7-9 months. Scientists think butterflies use a range of environmental cues to find the overwintering sites, such as the Earth's magnetic pull and the position of the sun.

To find out more about over-wintering in NZ, click on the button below.

Overwintering in NZ

Predators of Monarch caterpillars

Unfortunately, many caterpillars do not survive. Despite the warning colouration of the caterpillar and tthe toxins they acquire from the swan plants, there are many other insects that prey on them.

Eggs and very small caterpillars: can be eaten by ants, ladybirds, shieldbugs and spiders. Newly hatched caterpillars can also eat nearby monarch eggs. There have been reports that small caterpillars can be cannabilised by larger caterpillars.

Larger caterpillars: The main predator are wasps. For me, it is the Asian paper wasps. I have even seen wasps attack a newly formed chrysalis. While they also feed on the nectar of the swan plant, when they require protein to feed their own larva, they seek out vulnerable caterpillars (or other insects). Praying mantises probably eat them too.

The shining cuckoo also seems to be able to withstand the toxins of the monarch caterpillar.

Praying mantises also prey on butterflies that cannot yet fly.