How To Identify Monarch Butterflies

I’m as excited as anyone about supporting Monarch butterfly conservation efforts. We plan to buy several swamp milkweed plants to add to the existing trees, shrubs and flowering plants around our property.

A monarch rests on asters. Image courtesy of the National Park Service.
A monarch rests on asters. Image courtesy of the National Park Service.

I got to see the Monarchs many years ago while on a visit to Pacific Grove, Calif. I’m not sure, however, that I’ve ever spotted a Monarch in New Mexico, and a map I checked had a giant question mark for much of New Mexico and Arizona, even though our states border Mexico. Although singularly striking, Monarchs look similar to a few other butterflies. What’s more, the critical aspect of saving them requires providing habitats for the butterflies’ larvae. Enter milkweed.

A flowering milkweed plant in the pollination gardens at the Arizona-Sonora Desert Museum outside Tucson, Ariz.
A flowering milkweed plant in the pollination gardens at the Arizona-Sonora Desert Museum outside Tucson, Ariz.

Monarch life cycle

Monarch butterflies lay their eggs on milkweed plants, which also attract other pollinators. The Monarchs find milkweed even when it has finished flowering for the season. The eggs are tiny (about the size of the head of a pin), but as they take on adult form, the larvae, or caterpillars, emerge and grow rapidly.

Monarch butterfly lifescyle. Courtesy of the U.S.D.A. http://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/biology/index.shtml
Monarch butterfly life cycle. Courtesy of the U.S.D.A. http://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/ biology/index.shtml

Like many gardeners, I freak out a little when I see a big caterpillar on a plant. I can’t abide tomato hornworms and the damage they inflict, and we also have had branches of several small trees stripped by the io moth caterpillar. This bad boy stings and releases a poisonous substance that can irritate the skin or cause severe reactions in some people. Last summer, we found a similar greenish-yellow caterpillar on fennel plants, or what was left of them. I think I’ve identified them now with some research.

The io caterpillar is similar in color, but has a fuzzy, fluorescent look. And it stings!
The io moth caterpillar is similar in color, but has a fuzzy, fluorescent look. And it stings! Check out the stripped branches in every direction.

So, I wanted to be sure that I can easily recognize the Monarch caterpillar before trying to attract them to my yard. In fact, all gardeners who want to help the Monarchs should be able to recognize the insect in all forms. I would hate to hand-pick a Monarch caterpillar and end its life cycle! Strangely, finding quality resources to help me identify the caterpillars, and especially to share photos, did not come easy. I finally tracked down some information.

Monarch or Queen?

Although I don’t want to hurt the chances of any butterfly, I was relieved to discover that the caterpillars on the fennel were most likely Queen butterflies, not Monarchs. Queen butterfly caterpillars also feed on milkweed, and can share plants with Monarchs. The butterflies look really similar, but have a few distinctive differences.

Here's a Queen butterfly enjoying milkweed in fall at the Arizona-Sonora Desert Museum.
Here’s a Queen butterfly enjoying milkweed in fall at the Arizona-Sonora Desert Museum. Notice the white dots that extend toward the body.
Monarch wings look like stained glass designs. Image courtesy of National Park Service.
Monarch wings look like stained glass designs, and the color varies slightly throughout. Image courtesy of National Park Service.

Queen, Monarch and Viceroy butterflies have similar colors and patterns. Monarchs are a deeper orange, and the hue changes slightly throughout the wings. The best way to tell the adults apart is the location of white spots on the wings. The Queen butterfly has dots that extend into the orange areas of the wings. But Monarchs have a distinctive stained glass appearance and no dots outside the black edges of the wings. Viceroys are smaller than Monarchs and have triangular white dots under their wings.

Just to confuse matters: Here's a Viceroy adult. Courtesy of the NPS.
Just to confuse matters: Here’s a Viceroy adult. Courtesy of the NPS.

You can distinguish the Monarch caterpillar from other caterpillars by the antennae. The Queen butterfly has three sets of antennae and filaments, and the Monarch has only two – one antenna pair on the front end and a filament pair on the back end. The Queen caterpillar spots an extra set about one-third of the way down from the front. Viceroy caterpillars do not look like Monarch larvae; the Viceroy caterpillar has a brown, rough appearance.

Close-up of a Monarch caterpillar. Note two sets of protrusions, while the Queen has three.
Close-up of a Monarch caterpillar. Note two sets of protrusions, while the Queen has three. Image courtesy of NPS Photo/Alicia Lafever.

The Monarch young larva is nearly clear until it begins to eat milkweed and grow. The larval portion of the life cycle lasts about 10 to 16 days. They can become plump just before pupating, having eaten plenty of milkweed. The caterpillars move away from milkweed as they prepare to evolve to pupae.

Queen butterflies are pretty as well. This one enjoys a butterfly weed flower in Northeastern New Mexico.
Queen butterflies are pretty as well. This one enjoys a butterfly weed flower in Northeastern New Mexico.

Check the Resources page for excellent pages and videos on identifying and protecting Monarchs. Happy hunting and pollinating!

Got Bees? Join the Million Pollinator Garden Challenge

The number of honey bees and other pollinating insects is declining around the United States. Colony collapse disorder and other diseases, along with increased pesticide, use are likely culprits. What’s more, monarch butterfly populations have been declining by the millions!

butterflies on ivy blooms
We were stuck with ivy around all of our walls at our last home. We pulled out any that was rooted on our side of the fence. It’s not xeric and it is invasive, but butterflies flocked to the blooms.

On May 19, President Obama announced steps aimed at improving the health of pollinating insects. And in response, the National Pollinator Garden Network issued the Million Pollinator Garden Challenge. According to the network, pollinators help generate one out of three bites of food we eat each year. Planting plenty of trees and flowers that attract bees, butterflies, birds and bats can help improve pollinator health and populations.

The challenge calls on homeowners, businesses and communities to create and sustain gardens that attract pollinators. Let me just say that this is another concern I have about extreme xeriscaping, or a trend I see of replacing every bit of plant and lawn in a landscape with gravel. New Mexico, for one, is barren enough. And there are plenty of xeric plants that attract birds, bees and other insects and provide some color in the landscape.

maximilian sunflower
Maximilian sunflower (Helianthus maximiliani) is a native, low-water prairie flower that bees love. I love its late-season blooms.

According to the Million Pollinator Garden Challenge, a pollinator garden should:

  • Include plants that provide nectar and pollen sources.
  • Provide water for pollinators.
  • Be in a sunny location with some wind breaks.
  • Have large areas of pollinator-attracting plants that are native and noninvasive.
  • Include plants that bloom throughout the season.
  • If possible, eliminate pesticide use, and at least minimize pesticides.

If your garden already meets the criteria, I encourage you to go to the challenge’s website and add your garden to the map.

And here are a few tips for meeting the challenge, or at least for making sure you have plenty of bees, butterflies and other pollinators in your garden:

  • Of course, including native, low-water plants is critical. Look for symbols in product catalogs or lists of xeric pollinators. And remember bees love herbs too. They buzz all around our thyme when it flowers, and there are roses and other flowering ornamentals pollinators love that need nothing but rainwater once established.
woods rose attracting bees
This woods rose had bees all over it the other morning. It’s a native, wild rose that’s xeric.
  • Some people avoid plants that attract bees because of possible stings, especially with children around. I have a few plants that attract seemingly hundreds, and one we walk past constantly. But if bees bother you, just place your pollinator plants where you can see them, but in a spot you seldom sit or walk by, and not where the kids’ soccer ball always ends up when they play in the back yard.
  • Providing water can be tough. Our birdbath dries up in a day or two, and I hate to refill it, knowing it will evaporate. But I can use rain water. The birds also gather on the top of our rain barrels, where the water sometimes pools. Butterflies need only a few drops in a tiny rock or plate.
  • Some native plants bloom continuously with no effort on your part. Look for those! An example is catmint (Nepeta). And create a dense grouping with a mix of colors and bloom times to attract pollinators, especially if you have limited space. A few annuals can provide blooms when perennials fade. We have cosmos that pop up late in summer and birds balance on the thin stalks, gathering seeds.
yarrow and gallardia
Moonshine yarrow (Achillea millefolium) is a perfect pollinator. It blooms all season and has a flat surface for easy landing! Bees also love the annual blanket flower (Gallardia)
  • One of the great benefits of inviting pollinators with flowering plants is that they should make a side trip to your edibles. Don’t be afraid to plant some flowers near vegetables, as long as they don’t compete for sun and water or hide weeds.
  • If your roses or other plants get aphids, wash the tiny bugs off with a fine spray of water in the morning before turning to a pesticide; it’s just not necessary. Spray again in a few days if more return. And try to stick with pesticides on your edibles that are least harmful to honeybees, such as insecticidal soap.