Recently classified as an endangered species by the International Union For Conservation of Nature, the monarch butterfly is one of our most recognized insect species. For decades, gardeners, biologists, and entomologists have been watching the decline of these butterflies and pushing to get them on the list. But what does it mean to be on the endangered species list? Well, first of all, this is not the Endangered Species Act of the United States. But at some point, I would expect them to add monarch butterflies to that list.
Monarch butterflies are iconic not only because of their black and orange coloration, but also because of their migration pattern, and their food source. Across the United States, Canada, and Mexico, monarch butterflies are well known. Gardeners from Texas to Canada mark the first migrating butterflies heading northward from Mexico each year.
What is the life cycle and habitat of monarchs? How can gardeners protect monarch butterflies? What are the threats to monarchs on their journey? Lets dive into more about this amazing butterfly.
Life Cycle and Habits of Monarch Butterflies
Adult monarch butterflies undergo one of the most fascinating migration patterns of any insect species in North America. In California, however, monarchs remain year-round without migrating. East of the Rocky Mountains, monarch butterflies begin each spring at their overwintering sites in Mexico by breaking diapause and mating.
What is diapause? A period of suspended development in an insect, invertebrate, or embryo, due to environmental stress or unfavorable conditions. It could be considered a long sleep.
Once they have broken diapause, then they mate and begin to fly northward. This usually begins in February and March. As they fly north, the females lay eggs on milkweeds and a few other members of the Dogbane Family. A female monarch butterfly can lay between 100 and 300 eggs as she travels north. Many of these butterflies do not make it very far, but are often killed, eaten, or are worn out before they even reach the Central Great Plains. Adults not in diapause live to 2 to 5 weeks.
What do Monarch Butterfly Caterpillars Eat?
I mentioned milkweeds and members of the Dogbane Family. Most of the plants in this family produce a sticky sap from their leaves and stems. Its this sap that helps the monarch become toxic to birds and animals. The bright orange coloration of the wings is a warning to predators that they do not taste good.
Throughout the Great Plains, from Texas to Canada, there are 20 plus species of milkweeds which monarchs can lay eggs on. From the Rocky Mountains eastward, there are 41 species available to monarchs, though many of these are limited to Florida. Besides milkweeds, monarchs may lay eggs on honeyvine milkweed (Cynanchum laeve), which is common from the Great Plains eastward.
What Happens After Monarchs Lay Their Eggs?
After adults monarchs lay eggs, the eggs hatch 2 to 5 days later. The caterpillars will eat all parts of the milkweed plant, including leaves, stems, and flowers. They progress through five instars, and shed a skin at each progression, before climbing off the plant (usually) to find a place to pupate. Then, they hang upside down and form a green and gold chrysalis, transforming into a butterfly in 10 to 14 days. If it is still spring or summer when they emerge from the chrysalis, then the adults continue to fly northward.
What is an instar? An instar is a phase between two periods of molting in the development of an insect. Usually recognized in caterpillars and insects with incomplete metamorphosis, such as true bug species. Think of it as a shedding of skin (think snakes) to get bigger. True bugs, grasshoppers, cicadas, and spiders all do this.
Sometime in the fall, after daylight begins to fade (likely around the fall equinox), monarchs begin their long journey southward towards their overwintering sites in Mexico, Texas, or Florida. In some cases, they can be picked up by ground radar systems and may travel as far as 3000 kilometers.
What Can Gardeners Do to Protect and Provide for Monarch Butterflies?
When is comes to what we as gardeners can do, the list goes on and on. One of the biggest things to do is to recognize the importance of both the adult butterfly and the caterpillar of the monarch. Once we realize that, we will stop using practices that harm or repel them from their gardens. One of the biggest challenges I face when dealing with homeowners or new gardeners is their unwillingness to allow caterpillars and insects to eat their plants.
But it is important to remember that all native insects are part of the ecosystem and we should try to encourage their abundance, which in turn encourages birds, other insects, spiders, reptiles, amphibians, and mammals, all of which are important in the garden.
Planting For Monarchs
Gardeners can get started by planning a garden specifically for monarch butterflies, or adding to existing gardens in a way that encourages them. You could plant a butterfly garden, monarch waystation, or designated natural area, alive with diversity of plants and insects. Or maybe just add a few containers of milkweeds to your rooftop or patio if you live in the city. There is always a way to help.
For gardeners in the Central Great Plains, Midwest, and Northeast, Zones 4 to 8, the following is a list of common milkweed species that are garden worthy, not being overly aggressive or weedy.
- Butterfly milkweed (Asclepias tuberosa) & cultivar ‘Hello Yellow’
- Swamp milkweed (Asclepias incarnata) & cultivars ‘Ice Ballet’, ‘Cinderella’, and ‘Milkmaid’
- Spider milkweed (Asclepias viridis)
- Purple milkweed (Asclepias purpurascens)
If you have the room for it, planting a meadow garden or natural area with grasses, forbs, and annuals can work well with the following milkweeds.
- Common milkweed (Asclepias syriaca)
- Showy milkweed (Asclepias speciosa)
- Whorled milkweed (Asclepias verticillata)
- Prairie milkweed (Asclepias sullivantii)
Besides the milkweeds, monarch butterflies visit other flowers for nectar on their journey northward, and again back south. If you want to plant to help them, as well as for other pollinators, try to plant some of the following flowers in your garden spaces.
- Blazingstars (Liatris species)
- Goldenrods (Solidago species)
- Joe Pye Weed (Eupatorium species)
- Purple coneflower (Echinacea purpurea) & cultivars
- Rattlesnake master (Eryngium yuccafolium)
- Asters (Symphyotrichum species)
- Butterfly Bush (Buddleia davidii) cultivars
- Sedum (Hylotelephium species)
- Buttonbush (Cephalanthus occidentalis) and cultivars
Add More Diversity, Use Less Pesticides
One of the biggest problems with today’s landscapes is lack of diversity, which often results in an increase in pesticides. And to protect and provide for monarch butterflies, you do not want to use pesticides. So how do we add more diversity to the landscape. The first step is to do an inventory of what you already have. Make 3 columns, one each for natives, nonnatives, and cultivars of natives (nativars).
If you have 5 maples, and 2 are native, 2 are cultivars, and 1 is nonnative, put them in their respective columns. It might look something like this.
NATIVE – Sugar maple x 2
NONNATIVE – Paperbark Maple x 1, Norway Maple x 1
NATIVAR – Autumn Blaze Maple x 1
Once you have an inventory of the plants in your landscape, add all the numbers together and then get the percentage of native versus nonnative versus cultivars. This will tell you how diverse your landscape is. If your landscape is quite diverse, you should have at least 25 different species of perennials, 10 species of shrubs, and 5 to 10 species of trees. There should be a good mix of natives and nonnatives, heavier on natives.
After figuring how diverse you landscape is, you can plan to add more in if necessary. The more diverse your landscape is, the less need for pesticides. This is because beneficial insects are attracted to a wide variety of perennials, shrubs, trees, and annuals. If there is a pest outbreak, there are usually enough predators to get it under control in a few weeks. But if you use pesticides in the landscape, you deplete predators and may actually cause bigger pest outbreaks in the future.
Threats to Monarch Butterflies
What things are mostly outside of the gardener’s control that affect monarchs? There is a lot of potential for population decline in monarchs. Factors include insecticide use, habitat loss, and mechanical harm.
Habitat Loss And Pesticides
Unfortunately for us and the monarch butterfly, farming causes a lot of concern. Do not get me wrong here, I come from a farming family, and there are a lot of challenges to a compromise. The 2 biggest concerns are pesticide use and habitat loss.
Since World War II, pesticide use, especially herbicides and insecticides, has increased astoundingly. Things like Agent Orange and DDT caused a lot of problems for people and wildlife in the late 1900s. Because of that, and the now ever-present glyphosate-enhanced crops, habitat loss for monarch butterflies just increases.
Glyphosate, is an herbicide which is non-target specific, unless adapted through plant breeding to accept its genes. This means that is kills everything. Even though overuse has created “super weeds” which are also resistant, many plants have no defense against it. Milkweeds are included in those with no resistance to herbicides.
The other big problem with farming is really happening right now, but it is not the farmer’s nor the consumer’s fault. Japanese beetles have been sweeping across the country, eating everything in sight, including corn and soybeans, which are 2 of the biggest crops in the Great Plains and Midwest. Because of Japanese beetle pressure, farmers are forced into using more insecticides on their crops, affecting both the beetles and native insects, including the monarch. Even if the spray is not directly sprayed on the monarchs, it can cause disorientation, sterility, and death with small amounts of use.
What does that mean? How many times have you been driving down the road and hit a monarch or other butterfly. I have done it thousands of times. Kills by cars, planes, and even trains can add up when your population is already suffering from habitat loss and pesticide death. And there is no good solution here either. The best way would be to dig tunnels across the U.S. and drive underground, or at least for all roads over 55 mph. But that would mean a major infrastructure change (although it would be great for winter travel).
There are a lot of things a gardener can do and plant to help monarch butterflies in their own gardens. And while there are certainly some major concerns as to the future of the monarch, we can and must be aware of the issues surrounding them, and be prepared to help them as best we can.