The Monarch Butterfly Reproduction Cycle
The monarch butterfly, while beautiful to witness, isn’t born as beautiful as it becomes. There is a total of 4 stages in the monarch butterfly reproduction cycle. As with many other animals and insects, the monarch butterfly first starts out as an egg, which is laid by a female monarch on a milkweed plant. Though it is hard to know just how many eggs a single female monarch butterfly lays in any given season, it is estimated that a single mother will lay between 100 and 300 eggs during her lifetime. A monarch egg can hatch in as little as 3 days, and can post-pone hatching up to 8 days. This is a much faster time frame than many other egg-born animals.
Once a monarch egg has hatched, it becomes a larva and lives in the milkweed plant it’s born into. The first thing it will eat is its own eggshell…weird, right? Once it has eaten it’s eggshell, it will then for the next two weeks or so, eat the milkweed that it lives in, which not only helps it grow as a caterpillar, but also provides it with defensive properties to protect it from it’s predators. These defensive properties are toxic compounds that make the caterpillar poisonous for predators to eat. Through the miracle of nature, predators know not to eat the monarch caterpillar to avoid being poisoned.
After roughly two weeks, the monarch caterpillar becomes full grown for its larva stage, and makes its journey to find a suitable place to become a pupa, or what’s more commonly known as its chrysalis.
The monarch caterpillar will find a suitable, sturdy twig or leaf and attach itself using its hind legs. Once it attaches itself to its secure spot, it begins to produce silk to hang from upside-down. The caterpillar will then shed its skin, revealing a hardened shell made of protein. This becomes the shell that it will use to go through metamorphosis. Due to the fact that this stage is when it’s at its most vulnerable, it will often try to find a place that its chrysalis can blend or camouflage into, to avoid being seen or disturbed by potential predators. Note that a butterfly’s chrysalis is not the same as a moth’s cocoon, because it is not wrapped in a silken outer layer.
Once a monarch caterpillar has evolved into a butterfly, it will then find a mate to produce more eggs. Though butterflies can’t talk to each other, they use colors and smells to find a suitable partner. The male monarchs attract their female counterparts by releasing a special chemical, or smell, from glands that can be found at the rear of their wings.
Once a male and female butterfly have mated, the eggs are laid by the mother monarch almost immediately, usually at the base of a milkweed leaf. While the first few generations of monarch butterflies during a season only live for two to five weeks after fully growing, the last generation, which is born towards the end of summer and beginning of fall, will be the ones who migrate to a warmer climate for the winter. This generation is the lucky one, as they tend to live for up to nine months, as it’s their responsibility to return to their homeland, mate, and reproduce to begin the next season’s first generation of monarch eggs.