Crawlies with Cri: Monarch Butterfly

Monarch Butterfly (Danaus plexippus) in all their stages: Egg, caterpillar, green chrysallis, clear chrysallis and adult.

With May being “first month to spot a monarch” month and Shady Cove becoming a Mayor’s Monarch City, this week we’re going to revisit those iconic orange butterflies.
Hopefully you’ve met a monarch in real life, but some children and even teens these days may never have seen one.
Meet the monarch butterfly (Danaus plexippus). The good news is there are monarchs around our area, but you do need to find milkweed to see them.
If you plant milkweed native to Southern Oregon in your yard, you’ll get to see them without going on a road trip.
We have a few species to choose from: showy milkweed (Asclepias speciosa), narrow-leafed milkweed (Asclepias fascicularis), pallid milkweed (Asclepias cryptoceras ssp. cryptoceras) and purple AKA heart-leafed milkweed (Asclepias cordifolia).
If you want to help monarchs, planting native milkweed is the best thing you can do. While there are some colorful, fancy species of milkweed native to other parts of the United States, you only want to plant those four listed species here in Southern Oregon.
Most people know monarchs are in decline, but may not know much about them in general, so let’s learn the basics.
Monarchs aren’t the only butterflies partial to milkweed; they are in the Tribe Danaini – Milkweed Butterflies – which has four milkweed munching species. Not only is milkweed sap toxic, which helps keep these butterflies safe from predators, but it’s tricky to eat milkweed because of the sap’s sticky properties.
How do monarch caterpillars manage? They have a nifty behavior called “trenching.” Now, in addition to being toxic and sticky, milkweed sap is high pressure stuff, so it quickly flows out to gum the mouthparts of any insect that tries to chew the leaves.
To get around this pressure, a young monarch caterpillar cuts a semicircular trench on the underside of the leaf, severing veins and creating a low-pressure zone downstream of the cut. The caterpillar then has a safe, low sap area on which to feed.
The caterpillars munch on milkweed leaves and grow for about two weeks. Once they’re about two inches long, they morph into that famous green chrysalis. They hang out in the chrysalis for another two weeks before they eclose (hatch out of their chrysalis).
You can tell a monarch is about to eclose because the jade green chrysalis will become crystal clear. It appears that it has “darkened” but really the dark you see is the adult butterfly inside.
Depending on how early or late in the season the monarch hatches it may only stay around doing butterfly things for a few weeks and then die.
What about migration?
Those born later in the season will migrate south. There are about four generations of monarchs born each summer. The migratory ones return the following year to restart the cycle. Oregon monarchs overwinter in California. More eastern populations go all the way to Mexico.
California’s overwintering monarchs mainly gather in huge groves – with tens of thousands of adults – in Pismo Beach and Pacific Grove. There are several other spots in California where small groves may gather.
Adult monarchs are sizable butterflies with a wingspan of about four inches. Those wings sure must help with their long migration.
Because they are poisonous to most birds (a few species have figured out how to safely eat them) they can afford to be big, bold, beautiful and iconic.