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Monarch caterpillars molt (shed their skin) five times throughout their larval stage. The "skin" that is left behind is actually the caterpillar's exoskeleton. An insect's skeleton is on the outside, as opposed to on the instead like mammals, fish, reptiles, amphibians and birds. Endoskeletons provide support inside the body in the form of bones and cartilage, whereas As caterpillars grow, their exoskeleton gets too tight, so they need to shed it in order to continue to grow. Each molt results in a new "instar" stage. Therefore, when the egg hatches, that tiny 2 mm caterpillar is in its first instar stage.


It will molt three more times and grow exponentially over a couple of weeks. Each stage lasts 3-5 days. The fifth and final molt is when the fifth instar caterpillar becomes a chrysalis.


Environmental News & Blogs


 Western Monarch New Year's Count numbers are in.
Sadly, it's not great news...


Western Monarch Butterflies Clustering at Natural Bridges State Beach

Although our western monarch population appeared to rebound unimaginably for the second year in a row, the numbers from the New Year's count weren't quite as inspiring. The final Thanksgiving count numbers topped 330,000 monarchs, which is incredible. However, due to unseasonably cold, windy and wet weather on the California coast, more than half of the monarchs did not make it. A typical year will see a decrease between 35-49%; however, the loss this year is estimated at 58%, with only 116,000 monarchs reported. This illustrates just how fragile our monarch populations can be. One bad winter, and we've lost more than half of our western population. Remember, these are the same monarchs that made the long trek from the Rocky Mountains to the California coast in the fall. 

How can you help? Even if you live in an apartment or have a very small yard or garden, plant native plants and milkweed. Plant, plant, plant! And do this without the use of pesticides. If you plant both spring and fall flowering native plants, migrating monarchs will have plenty to eat on their way out of their overwintering grounds in the spring, and the last generation of the year will have plenty to fuel them on the way in to those same sites in the fall. If this all sounds very simple, that's because it is! You can actually help this species by simply picking up (ask your local nursery to carry pesticide-free native plants) or ordering plants and sticking them in the ground. Here are two great resources to get you started:

Xerces Milkweed Seed Finder

NWF Native Plant Finder

 Western Monarch Thanksgiving Count Numbers are in!


Western Monarch Butterflies Clustering at Natural Bridges State Beach

Every year, the Xerces Society for Invertebrate Conservation (Xerces) conducts a western monarch population count. Hundreds of volunteers count clusters of monarchs along the California coast at numerous overwintering sites. In 2020, the western population reached an historic low of fewer than 2,000 monarchs counted. Last year, a remarkable uptick occurred, with nearly 250,000 monarchs counted. Monarch biologists were a bit baffled, and naturally cautiously optimistic. There is no one reason for this sudden and miraculous rebound. It could be that outreach/education efforts were finally seeing results and the public planted more milkweed or native flowering plants for both spring and fall migration. Or maybe people finally realized how terrible pesticides are for monarchs and have learned to live with a less than perfect lawn or garden. It could be that during migration, the weather was more cooperative, and fewer monarchs were lost in the fall. It's hard to say what the reason or reasons were, but this year, the count was even higher! The final tally (before the historic storms that battered the west coast in January) was 335,479 monarchs! That's absolutely incredible and a number that should be celebrated. The bad news, is that we don't know exactly how many were lost during the devastating storms. 2023 will certainly be an interesting year for monarchs as we hold our collective breaths and wait to find out just how much they were impacted by severe weather at the start of the year. 

IUCN Monarch Listing

On July 21, 2022 the migratory monarch butterfly was officially listed as "Endangered" on the Red List of Threatened Species by the International Union for Conservation of Nature (IUCN). See full details here. Although this is an important step for monarch conservation and recognition, this listing has nothing to do with listing under the Endangered Species Act (ESA), which offers federal protection. A final ruling for the listing of monarch butterflies by the US Fish and Wildlife Service is scheduled for 2024. 

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