Raising Monarchs: Watch for Predators

This year I was so hopeful. My yard has been cultivated, or perhaps a better term is 'uncultivated,' in hopes of creating an oasis of beneficial insects. I neglected to reapply mulch, leaving a bare patch of soil in my planting bed. It soon became a delight to my kids to watch songbirds taking dust baths. I let the violets have their way, and they rewarded us with an outstanding flower show this spring and an excellent groundcover up until mid-summer when the heat and sun forced remaining violets into the shade.

A small birdbath placed on the ground became home to toads, frogs, and dragonflies. We kept mosquitoes at bay with Bti treatments. A family of paper wasps selected a spot under our eave to build their nest. Knowing their beneficial qualities, I decided to give the wasps a pass, watching closely should they become aggressive. Purple coneflower, Arkansas blue star (Amsonia hubrichtii), thyme, Ohio spiderwort (Tradescantia ohiensis) bloomed, bringing pollinators of all shapes and sizes. Finally, after two years my three patches of swamp milkweed (Asclepias incarnata) were established.

We saw our first monarch around mid-June. She drank nectar from the milkweed bloom and then laid her eggs. She was soon followed by another butterfly and another. In total, I spotted four monarch butterfly females laying their eggs in my backyard before July. And boy did those monarch caterpillars eat!

My kids watched alongside me as the caterpillars munched and grew. We were not able to focus much on the caterpillars much after June 23 as that was the date we welcomed our third baby boy into the world. Let's just say we were a bit distracted. I would occasionally emerge from the house to check on the garden. Every time my inspection of milkweed yielded no monarch caterpillars. Odd I thought. The caterpillars should not all have transitioned to adult butterflies yet. In fact, the feeding of the leaves suggested the caterpillars had been absent for some time.

This mystery remained unsolved throughout July. Monarch butterflies were also scarce. Checking in at the Extension office's monarch waystation, it was a similar situation, no adults and no caterpillars.

About two weeks ago, we welcomed a monarch female butterfly into our backyard. I followed her from milkweed to milkweed and made a note of where she laid her eggs. Soon after, I found two baby monarch caterpillars, happily eating milkweed.

The next day, the caterpillars were nowhere to be found. Puzzled, I checked the other patch of milkweed where I knew the female had also laid eggs. Just in time, I spotted a yellowjacket wasp, grasping what appeared to be a tiny monarch caterpillar, take off from the milkweed. That is when the gears clicked into place. The monarch caterpillars are being hunted by the same beneficial insects I was encouraging to my yard!

All types of beneficial predators frequent my backyard, most being wasps and hornets. Ingesting the toxic compounds of the milkweed does make the monarch caterpillar poisonous or distasteful to many predators. However, some have adapted.

It seems the paper wasps, whose nest I spared, are a primary wasp predator of monarchs. Yellowjackets have also been observed feeding on monarch caterpillars, which also setup shop in my backyard. You can read more about them in my previous post on yellowjackets.

This experience drives home the statistic that only 10 percent of monarchs survive the egg and larval stage. While planting milkweed and nectar sources are a necessary strategy to promote monarch numbers, there is more that we can do.

Monarchs raised in captivity have a much higher survival rate of 90 to 99 percent. If you want to give your monarchs a leg up on the competition in the wild, consider bringing them inside and placing the caterpillars in a rearing cage. Cages can be purchased online or built out of a tomato cage wrapped in fine netting. You can even raise monarch caterpillars in plastic containers. (Just be sure to provide good airflow.)

If you want to learn more about monarch butterflies, join us for our annual Monarch Migration Festival on September 9, 2017, at the Lakeside Nature Center in Galesburg, Illinois. It is a fun-filled day starting at 10 AM with activities for the whole family.

  • You will see real live monarch butterflies and caterpillars
  • Explore the Ms. Mari Posa mobile classroom
  • Adopt a tagged monarch butterfly
  • Send your own symbolic butterfly to Mexico
  • Purchase native plants (The first 50 families will receive a free native plant!)
  • Learn about beekeeping
  • Talk to local conservation experts
  • Build monarch rearing cages
  • Enjoy vendors, music, food, crafts, talks, and of course butterflies!

Check out our event page on Facebook and web page!

Find more information on rearing monarch caterpillars indoors HERE.