Core conservation message for students
It's essential that teachers include a conservation message when raising monarchs in a classroom. Without that message, we can't justify removing the few monarchs from the wild that we need for producing eggs. If monarch populations continue their decline, a time will surely come when we will be prohibited from removing any wild monarchs.
Obviously, these messages will be modified to suit the age of your students. I believe many kids will understand more of the ideas below than you now think possible.
Monarch numbers have been decreasing for a long time. Their populations are now down to roughly 10% of what they were--a level many would consider putting them in danger of extinction. They are counted during the winter in Mexico by measuring the area occupied by trees with dense clusters of wintering monarchs.Pesticides--one cause of the decline: The "neonics" (neonicotinoids) are a recently introduced pesticide that is now among the most widely used. It was thought to be "safe" because it is non-toxic to mammals and birds. However, neonics are extremely toxic to all insects. It spreads from the fields where applied and widely contaminates the environment. At the levels you can find in areas away from fields, it is known to be quite harmful to insects, including those living in water. It doesn't break down in the environment, so it will continue to decimate insects for many years after application.
Habitat loss--another cause of the decline: This includes what monarchs need to survive--most important are milkweed plants (there are many species). In the US and Canada, habitat loss is caused by urbanization and the intensification of agriculture. Intensification means more fields and more intensive activities, like the use of herbicide (which eliminates milkweed plants). In Mexico, the trees that monarchs need for safely roosting in the winter are being cut down.
Oher causes: Climate change means that summer or winter habitat may become too hot or dry, directly affecting monarchs or changing vegetation. Flowers monarchs need for nectar, or milkweed they need to lay eggs on may not be growing when the monarchs need them. Vehicle collisions with monarchs along highways take their toll. Predators on monarchs (such as fire ants in Texas) may increase because of climate change.
Monarchs are a stand-in for other insects people never think about. Insects support the whole ecosystem on land. Insects worldwide are in decline. Since insects are the main food for many animals such as songbirds, birds are also in decline. Let students handle monarchs to combat the widespread fear of insects.
Teach the monarch life cycle with this added emphasis: Monarchs have "complete metamorphosis," meaning the immature stage (caterpillar) is completely different from the adult (the butterfly). Four orders of insects have complete metamorphosis: the flies, the beetles, the ants/bees/wasps, and the butterflies/moths. If you consider the importance of these four groups on the planet Earth, compared to humans, the critters with complete metamorphosis would easily outclass humans, or even all mammals as a group. The best way to evaluate importance of a group is by total weight, called "biomass." Metamorphosis isn't a quirk or a "curiosity" --it's easily the most successful lifestyle on Earth!
Monarchs and other insects have enormous value to us. Monarchs, through their amazing migration, tie the US, Canada, and Mexico in a bond of mutual experience and friendship. They provide an enormous economic service through pollination of crops. Without flies and beetles, the earth would quickly be buried in garbage as recycling of nutrients stopped.
You can make a difference. Planting milkweed or converting part of a lawn or schoolyard to native plants (providing nectar for butterflies) has benefits to humans as well as monarchs: Research shows green areas around schools increase student health, alertness, and test scores. Green areas with native plants reduce air pollution which is an underappreciated threat to our health. It's easy for students to harvest and plant milkweed seeds. Get students actively involved to combat passivity that's so widespread!
We'd love to hear about how you teach these ideas.