Monarchs and milkweed and "doing no harm."

Male monarch overwintering at Lighthouse Field, Santa Cruz

I took a walk recently at Lighthouse Field in Santa Cruz to see the beginning of a restoration plot beside a Monarch Butterfly roosting spot, in a eucalyptus and Monterey Cypress grove, just a mile or so from the much more famous spot at Natural Bridges State Park.

I had planned to go to a restoration work day there a couple of weeks ago while babysitting two of my grandchildren, but they were ill. So I wanted to see what had been done. The area has been cleared of weeds and roped off, ready for planting.

Area cleared and ready for restoration planting

The restoration is being done by the amazing West Cliff Ecosystem Restoration group (Facebook page) - whose mandate is to restore local coastal habitats. The idea is to give the Monarchs some nice local native nectaring plants to enjoy during their stay at Lighthouse Field, which is just across West Cliff Drive from the Santa Cruz Surfing Museum.

While there I happened to espy a fellow looking at the butterflies through binoculars. So I sidled up to say hello.

Someone interesting watching Monarchs? Yes - John Matusik

He had a State Parks baseball hat on. John Matusik, it turns is a well-informed docent at Natural Bridges, passionate about birds and butterflies, and he told me a few surprising things I did not know.

For example, the monarchs (Danaus plexippus to give them their scientific name) all around us were 100% males. Males who were still alive only because they had failed to mate. They were living on the caloric content of the packet of sperm they had failed to deliver to a female. They were probably not even nectaring, just having a last frolic in the sun.

(Digression - I sometimes think of my post menopausal life as having a last frolic in the sun! Mother nature does have some need for us grannies - but the young 'uns could get along quite well without us. This is our bonus time! So I identified with those supernumerary males flapping about in the sunshine, in a non-scientific sort of way.)

One of the many interesting things Mr. Matusik told me is that Monarchs don't breed here in Santa Cruz: Milkweed, which is their larval food -- the alkaloids in it make the butterflies toxic to predators -- is not locally native here!

Monarchs overwintering in non-native blue gum eucalyptus trees don't actually breed here!

I turned to to check this out. For Santa Cruz County, two observations are recorded for narrow-leaved milkweed, Asclepias fascicularis, the species that is local to our larger region as well as present in many other parts of California. Both observations were made in the upper reaches of Forest of Nicene Marks SP, which starts near the coast and spreads out as it rises quite high into the Santa Cruz Mountains. Both observations are high up, not too far from where an observation is noted for neighboring Santa Clara County, for which 22 observations are noted.

So the startling conclusion is: planting milkweed in our winter resting places might actually change the butterflies' migration patterns.

Photo of newly emerged Monarch by John Matusik

Mr. Matusik also told me that people actually artificially breed Monarchs so they can release them into the sky at weddings.

Another brief digression: ACK! I don't like that. I also don't like releasing balloons. What's wrong with rice-paper confetti, guys? - or how about pennies? When I was a wain (wee one) in Glasgow, Scotland, the departing newlyweds  would fling pennies from their car and all the wains in the neighborhood would yell "SCRAMBLE!" - for that was what we called this wonderful tradition -  then we'd run to pick up pennies, buy penny caramels, and ruin our teeth.

So - do I plant the showy milkweed seedlings that I've grown from seeds gathered in Ms. Town Mouse's garden last year?  Here is a quote from article on that says - milkweeds are not just for monarchs:
They also provide food or shelter for a diverse array of other insects, including nectar-seeking bees,  flies, and butterflies, and such specialist herbivores as seed bugs, longhorn beetles, and leaf beetles. Native milkweeds are clearly worthy of wider adoption.
In a garden, as long as plants are not invasive in any way (including cross-breeding with nearby natives) -- do your thing, I say. Along with a recommendation that your thing be to support local native plants and wildlife!

In other words -- garden so you Do No Harm - as Mr. Matusik said during our conversation.

Now, since we apparently don't have a local species around here, and since I've never actually seen a monarch butterfly up here on our ridge anyway - I think I'm safe in adding this attractive plant to my garden, for the benefit of other wildlife -- though not for the original reason I grew it!

Am I rationalizing? Yeah, probably ;-)

Photo of showy milkweed, Asclepias speciosa, from Bangor Daily News web site.

The rest of this post is about monarchs - I can't let Mr. Matusik's riveting info go to waste!

Are Monarchs Even Native Visitors to Santa Cruz County?

Mr. Matusik also wonders -- would Monarchs even be here if not for the relatively recent introduction of the Australian eucalyptus trees?

He notes that no Native American legends about monarchs survive among local tribes here, whereas in other regions, wherever there are monarchs, there are legends. I forget the details he mentioned about that so I can't point you to specific legends.

On the other hand, The Monarch Program has another theory about why nobody noticed Monarchs overwintering in California:
People probably did not notice monarchs roosting during the winter before the arrival of eucalyptus trees in the early 1850’s because they were greatly camouflaged on native tree leaves in remote areas; especially western sycamore (Platanus racemosa), Torrey pine (Pinus torreyana), Monterey pine (Pinus radiata), and Monterey cypress (Cupressus macrocarpa). 
However, they are talking about European botanists. I doubt that their point would apply to the people who have been living here for more than 10 thousand years, noticing all the tiny things you would do if you were living off the land.

More about Monarch Migration

FYI here are some other facts about monarch migration kindly shared by Mr. Matusik, that blew my mind.

The impregnated females from our area fly to the Santa Clara and Almaden Valleys, just over the Santa Cruz Mountains from us, and breed there, and die. The next generation then begins the multiple hop north, breed-new generation, die; hop north, breed-new-generation, die journeys, each about a couple months long at most.

Each migrating generation following the milkweed - until the northernmost end of their migration journeys -- as signaled to the emerging butterflies by --


And then there is the fact that it's probably getting a bit too chilly for a romp in the hay, so to speak.

So the generation that emerges at the northernmost point does not mature. Instead it makes the loooooooong journey south, like sliding down a snake in a snakes and ladder game back to square zero. There they overwinter, and then suddenly one day when something triggers their hormones - they grow up, mate -- and it starts all over again.

Santa Cruz and Pacific Grove are well known areas near me where groves of butterflies gather to overwinter. Which is great for those who live here or visit between October and around January.

But you can read about this and much more in several great sites such as this Forest Service page or The Monarch Program site.

* REFERENCES given to me by Mr. Matusik for the photon counter fact:

  • Zhu H, et al. Cryptochromes define a novel circadian clock mechanism in monarch butterflies that may underlie sun compass navigation. PLoS Biol. 2008;6:e4. [PMC free article] [PubMed]
  • Sauman I, et al. Connecting the navigational clock to sun compass input in monarch butterfly brain. Neuron. 2005;46:457–467. [PubMed]
  • Kyriacou CP. Clocks, cryptochromes and Monarch migrations. J Biol. 2009;8:55. [PMC free article] [PubMed]
  • 26 OCT 2015: Navigational Mechanisms of Migrating Monarch Butterflies. Steven M. Reppert, Robert J. Gegear, and Christine Merlin. Trends Neurosci. 2010 Sep; 33(9): 399–406.


Terra Hangen said…
I hope where they breed, over the Santa Cruz Mountains, is protected for them. I have visited Natural Bridges where they spend some months, and have seen them in the eucalpytus trees.
Town Mouse said…
My showy milkweed is completely dormant until May and goes dormant again in October. Maybe you don't need to worry too much about it?