Life Cycle of the Monarch Butterfly
Butterflies undergo an unusual process called metamorphosis, or a change from one thing to another. They hatch from their egg as a tiny caterpillar, and grow bigger and bigger over few weeks until they are ready to become a chrysalis. They emerge from the chrysalis two weeks later with wings! Each stage takes about 2 weeks, so the entire lifespan of a monarch may only be 6 weeks after hatching. There is an exception for the late-season monarchs who migrate to Mexico for the winter before returning north in the spring. The migratory Monarchs start the life cycle all over again upon their return, by mating and laying eggs. They then die shortly thereafter.
You can tell the difference between a male Monarch and a female. The male has a small black spot on both of its hind wings. On other butterfly species, this spot is used to release pheromones to attract a mate. However, scientist still are not sure what the Monarchs use it for. Females also have thicker veins, giving them a darker appearance.
Monarch Caterpillars Munching on Swamp Milkweed
Monarch Egg and a lady bug on a Tropical Milkweed
How Butterflies See
Butterflies have compound eyes, which are made of of thousands of little faucets. Each faucet can see a certain variety of colors. Butterflies can see the colors blue, red, green, purple, and ultraviolet light, which humans cannot see. Flowers have developed ultraviolet patterns on their petals, which act as "landing strip" or a "bulls eye" to entice pollinators to them. Butterflies also have ultraviolet patterns on their wings to distinguish them as male or female during the mating season. Butterflies are attracted to bright colors. They know that they can find food in flowers that are purple, blue, and red. Only female Monarchs look for the color green, and only when searching for milkweed to lay their eggs on.
They have color constancy, which means they can be trained to fly towards colors they have learned provide food! We are hoping this will be useful in the lab, while gathering flight data.
Photo by: http://www.nikon.com/about/feelnikon/light/chap02/sec03.htm
How Butterflies Fly
Butterflies do not just move their wings in an up and down flapping motion, which is what makes them so interesting to us here at the lab. They actually tilt those wings forward and backward during the up and down motion, making a figure eight. This allows them to efficiently move through the air with no struggle. Butterflies also take advantage of any wind drafts they find, allowing them to glide from one flower to the next with even smaller effort wasted. Their wings are massive compared to their tiny bodies, which help them to maneuver quickly through the air.
What Butterflies Eat
Butterflies predominantly eat nectar from flowers, but they also find nutrient deposits in mud, rotting fruit, and tree sap. Monarchs love milkweed, butterfly bush, lantana, and so many others! Many people confuse butterfly host plants as being the only flower that butterfly will eat from, but in reality, they are much healthier when given a large variety of nectar sources in the garden.
Host plants provide food for the baby caterpillars. In the Monarchs case, the host plant is milkweed, of which there are several kinds. Monarchs know that their caterpillars can only eat the leaves of milkweed, so they will not lay their eggs on any other plant!
Differences Between Butterflies and Moths
Many people mistake moths as butterflies and vise versa. Below is a list of some general ways to distinguish between the two, but there are some exceptions to these rules:
- Butterflies have thin antennae while moth antennae are large and feathery. Antennae are sensory organs used to feel things.
- Butterflies are usually larger than moths, but not always.
- Butterflies are also usually more colorful than moths.
- Butterflies create chrysalises during the pupa stage, which are made from their own body secretions. Moths create cocoons which involve a silk covering and usually include some bits of the moth's natural surroundings, such as leaves and pine needles.
- Butterflies are usually diurnal (awake during the day) while moths are usually nocturnal (awake during the night).
- Butterfly fore and hind wings are separate from each other. However moth wings are connected to each other by a small membrane called a frenulum. This keeps the wings moving together during flight.
A Monarch Caterpillar creating a chrysalis. The caterpillar finds a branch to hang upside from, and the secretions start from his head and works itself up to its feet. The chrysalis is very soft for a few hours, but it slowly hardens to become a protective shell. They are still very yielding so care must be taken when handling them.
This photo of a Luna Moth proves that not all moths have drab brown colors. However, we can identify this as a moth as it has large, feather antennae. Fun Fact: you can tell the difference between male and female Luna Moths by their antennae. This one shown is a male because the antennae are thick and wide. Females have much thinner antennae but are still feathery, and distinguishable as moths.
The Dangers To Butterflies
Caterpillars and Butterflies have a very difficult life out in the wild. As babies, caterpillars are easy prey for larger insects such as ants, preying mantises, and wasps, as well as birds. They are limited to their host plant for food, which them in direct competition with their siblings. The milkweed can sometimes become moldy, or become infected with a virus that is lethal to the monarchs. As chrysalises and butterflies, they are still in danger of birds. Their agile wings allow for quick maneuverability for escape.
Butterflies are in danger of herbicides and pesticides at all stages in life.