Milkweed is a lovely wild flower that grows in meadows around here. The flowers smell delicious. I made Milkweed ice-cream today. In the fall they make those big crunchy pods that explode with fluffy parachutes that sail their seeds around. This stripy caterpillar is eating the leaves of the plant, they are one of the only animals that can eat the leaves, because the plant exudes a toxic latex. There is also a beetle who can eat it, but if he’s not careful the milk can glue his mouth shut. The stripy Monarch caterpillars are able to digest the poison without getting sick, but it makes the whole caterpillar poisonous and they stay poisonous as adult butterflies. This is why nothing eats Monarchs. Any species that lived within the Monarch’s range who thought red, black and orange butterflies looked tasty died and didn’t pass their appetite for Monarchs on the their offspring because they were never born. This makes it very safe to look like a Monarch. Poisonous ancestors thoroughly cleared the way for their safe passage. Similar looking butterflies also enjoy this safe passage. Monarch caterpillars continue to enjoy Milkweed and eat nothing else.
Since parts of the plants are toxic (some parts are very nice for us to eat) they were banned in my province! Legally they are ‘noxious weeds’ and it is illegal for any one to let them grow in our gardens if they are anywhere near a cow field. (As I write this the neighbor cows are mooing. ) So Milkweed became endangered. And so Monarchs became endangered. In recent years there have been campaigns to plant Milkweed to save the Monarchs and it seems to be working. We went from seeing 1 or 2 a season 5 years ago to seeing at least 25 a summer. So keep planting Milkweed!
This Caterpillar is eating the plant that his mum chose to lay her eggs on, but she wasn’t born around here. She was born somewhere in the States. And her mom was born further south, and her grandma was born around Texas and her great grandma was born in Mexico and her great great grandma hibernated in a forest in Central Mexico. (I visited them a few winters ago, the place was dripping with millions of mating Monarchs. It was raining Monarchs. Trees drooped under the weight of Monarchs.) Each of these mother Monarchs successfully found a Milkweed plant to lay her eggs, but many of their sisters didn’t. Those caterpillars hatched on Maple leaves, or Burdock or Plantain and they all starved to death.
Since Monarchs take 5 generations to do their migration it’s important that we keep the farmers from destroying the grasslands, banning host plants and poisoning the world with insecticides and herbicides. We have to keep a safe path of Milkweed habitat all the way from Canada to Mexico.
The Biophilium 