It all started at the new yoga studio on State Street in Carlsbad. New owner Robert Mendez and I observed a group of caterpillars with black and green stripes voraciously chowing down on a small shrub in a cement planter in front of his studio.
We conferred with local landscaper Chris Bany and found that he had recently planted an Asclepias shrub as part of his container garden project.
As we took pictures of the caterpillars and searched entomology websites, we found out that this grouping was, indeed, part of the great monarch butterfly migration presently taking place in Southern California.
We checked on the caterpillars’ progress daily, but in one week they were all gone!
As we scoured the area, we found two bright green cocoons that had attached themselves to the side of the cement planter.
Now, I had taken entomology in my studies in horticulture in New York, but I had never seen quite that many caterpillars in one place. I started upon the journey to find as much information about the western monarch, which is presently gracing our local backyards and garden centers with its amazing metamorphosis.
After researching the western monarch migration with the help of the Xerces Society website, www.xerces.org, I can now describe the definitive life cycle of this elusive creature.
As we can all observe in our yards, the cycle begins as the male courts the female in a windward dance.
Finally, once they have mated on the ground, it is the female’s job to search for milkweed upon which she will lay her eggs. Within 3-15 days, the eggs hatch into larvae, which were the beautiful green-and-black caterpillars we were observing.
They then attach themselves to twigs and become somewhat iridescent green pupae. This pupa, if we observe it with the eyes of a hungry bird, changes daily, as the monarch develops inside the outer coating. In another two weeks, an adult monarch emerges and the cycle begins again.
As gardeners and lovers of wildlife, we can increase the chance of the butterfly’s survival by planting the correct host plants.
According to the expert staff at Anderson’s La Costa Nursery in Encinitas, there are three cultivars of Asclepias or milkweed, which the traveling butterflies prefer.
Staff members Danny Scavez and Hanna Faulstich gave me a tour of their extensive milkweed collection and cited the Asclepias fascicularis, Asclepias californica, and Asclepias speciosa as the caterpillar’s favorite food.
“They also like the tropical, non-native variety, Asclepias curassavica, but that one is not as helpful in the migration cycle because it does not go dormant,” noted Danny.
For anyone who loves the study of nature as much as I do, the website of the Xerces Society is incredible. Xerces Society is a science-based, nonprofit organization whose mission is the study of invertebrates.
Their in-depth, long-term studies can provide all nature lovers with hard facts of the decline of the monarch butterfly and maps out a plan for saving the declining species.
According to the Xerces Society website: “Once, millions of monarchs overwintered along the Pacific coast in California and Baja, Mexico — an estimated 4.5 million in the 1980s. But by the mid-2010s, the population had declined by about 97%, and starting in 2018, monarch butterflies had tough seasons in their migratory and breeding grounds in the western states. In the past two falls, the annual Xerces Western Monarch Thanksgiving Count showed that the population hit a new low: In both 2018 and 2019, volunteers counted under 30,000 monarchs — less than 1% of the population’s historic size.
“While these numbers are alarming, the real issue is the longer-term monarch decline due to stressors such as habitat loss and degradation, pesticides, and climate change — as well as other pressures on the migratory cycle of the monarch that we still have yet to fully study or comprehend. There are no quick fixes to solve all these large and complex forces, but we can still take actions NOW to help save the western population.”
If you would like to find ways to take part in monarch butterfly conservation, visit the Xerces site for on-the-ground technical support, long-term participatory studies for citizen scientists and suggestions for adopting ecologically sound pest management practices for the homeowner and commercial sites. I hope you have as much fun planting your Asclepias as we have!
Please send your questions and requests for further websites to me at [email protected]
Jano Nightingale is a Master Gardener and horticulturist who works on community gardens in North County. She previously served as the director of the Cornell University Master Gardener Program in Cooperstown, New York.
