You never know about those photo-bombers. You can't trust 'em.
So here I was, trying to photograph a tiny egg that a monarch butterfly had just deposited on our milkweed.
I held it up for a better look.
And then, the photo-bomber!
An oleander aphid, Aphis nerii, appeared out of nowhere and headed over to the egg for a quick "inspection."
Oleander aphids suck the juices, the very lifeblood, out of milkweed plants. They're yellow with black cornicles, they're non-native, and they're pests on milkweed when all you want are guests! (Like monarchs)
Want to know more about these pests? Check out the UC Statewide Integrated Pest Management Program's website on aphids.
"Aphids are small, soft-bodied insects with long slender mouthparts that they use to pierce stems, leaves, and other tender plant parts and suck out fluids," UC IPM says. "Almost every plant has one or more aphid species that occasionally feed on it."
They are also quite good at photo-bombing. Trust me.
So, folks, if you're in their migratory pathway and anticipate seeing them head toward their overwintering sites in coastal California, don't get your hopes up.
They're not coming. They are either non-existent or few and far between.
But we remember when they did.
Back on Labor Day, Sept. 5, 2016, a male monarch tagged "email@example.com A6093" fluttered into our pollinator garden in Vacaville. Washington State University entomologist David James traced it to citizen scientist Steve Johnson of Ashland, Ore., who had tagged and released it on Sunday, Aug. 28.
James calculated "No. A6093" flew 285 miles in seven days or about 40.7 miles per day to reach our Vacaville garden, which apparently is in a monarch migratory pathway. "Clearly this male is on his way to an overwintering colony and it's possible we may sight him again during the winter in Santa Cruz or Pacific Grove!” he said at the time. (No sightings reported.)
Still, it was a very good year for monarchs in 2016, as compared to previous years. We reared more than 60 in 2016. We saw dozens of migrating monarchs fueling up on nectar from the Mexican sunflowers (Tithonia rotundifola) and butterfly bush (Buddleia davidii). They arrived tattered and torn, and some could barely fly.
But come they did.
Not this year.
"It's been a very poor year for monarchs in the Pacific Northwest," James said. "In Washington, we had just two confirmed sightings of monarchs! This is the worst showing since I started taking records in 1999. I thought 2019 was bad (eight monarchs) but 2020 beat it."
"There were a handful of sightings in central and northern Oregon but they largely failed to cross into Washington," the entomologist said. "This is simply a result I believe of a very small overwintering population that had difficulty populating California and southern Oregon let alone locations further north."
"If future overwintering populations do not exceed more than 30,000, then this is what we can expect for the future; the monarch to be a rarity in Washington and BC."
Johnson, who rears monarchs in a vineyard in Ashland, says it was "a very poor year in the vineyard. We have three chrysalids right now and that will probably be it for us in the vineyard this year. They come from three 'cats that we found on the same day. We have seen far fewer monarchs than in any of the past years. Overall, to my knowledge, it has been a grim year in Oregon except for some isolated pockets."
Southern Oregon seemed to fare a little better for monarchs in the Pacific Northwest this year, James said, but "as Steve said, it was still way less than recent years."
"Idaho had quite a few monarchs, maybe as many as southern Oregon, but these arrived and bred from--I believe-- migrants that came from Mexico," the WSU entomologist said. "Populations in Arizona and Utah were also reasonable this summer. 'Leakage' 'of northerly spring migrants from Mexico is the ‘saving grace' of monarch populations in the West and may be the reason why monarchs can persist long-term in the West. This was a theory expounded by the late Lincoln Brower and I believe it has a lot of merit."
Johnson noted that the air quality in Ashland "at the moment (this morning) is 415—very hazardous."
How does all that poor air quality, all that smoke and ash from the wildfires raging across the West affect the migrating monarchs?
Thanks to James' tagging program and cooperators like Johnson, James now has "some limited data indicating monarchs do NOT have a problem migrating in very poor quality air. These data will appear in a publication I am preparing. Tagged monarchs released into poor quality air flew just as far and lived just as long as those that were released into good air."
Butterfly guru Art Shapiro, distinguished professor of evolution and ecology at UC Davis, who has monitored butterfly populations in Central California since 1972, has seen only six monarchs all year (the first one in Sacramento on Jan. 29) and "no eggs and no caterpillars at all." (See Bug Squad blog on his comments on "California monarchs on life support")
Naturalist Greg Kareofelas of the Bohart Museum of Entomology, UC Davis, has seen only one monarch all year and it was a female laying an egg on his milkweed in Davis. He is in the process of rearing it from egg to caterpillar to chrysalis to adult. It's a chrysalis now.
Lynn Kimsey, director of the Bohart Museum and UC Davis professor of entomology, and UC Davis forensic entomologist Robert Kimsey have not seen any in their Davis garden.
This year our Garvey family has managed to collect dozens of eggs and 'cats from our garden and rear them in three different batches. First batch: 5. Second batch: 11. The third batch? As of Sept. 1, we've reared and released 37 monarchs, with one chrysalis remaining. No. 38 should eclose in a few days.
Incredibly, our Vacaville pollinator garden seems to some kind of monarch magnet.
"I think Kathy and one gardener in the East Bay who is having a similar experience have all the monarchs in the region in their yards," Shapiro commented. "Very bizarre."
Very bizarre, indeed.
We don't normally name the monarch butterflies we rear, but we decided that the first one reared from an egg "The Greg Way" would be named for Greg--naturalist Greg Kareofelas, associate at the Bohart Museum of Entomology, UC Davis.
The first one, however, is a girl, so she's "Greta" instead of "Greg."
Over the last five years, we've reared more than hundred monarchs from caterpillar to chrysalis to adult. We collect the 'cats from the three species of milkweed in our Vacaville pollinator garden. This summer, however, we decided to collect a few eggs after seeing Mama Monarchs depositing them on tropical milkweed, Asclepias curassavica, and narrowleaf milkweed, Asclepias fascicularis. (As recommended, we cut back the tropical milkweed before the migratory season begins.)
Here's "The Greg Way":
"I put a single egg on its leaf in a small salsa container (the little plastic ones you would get at a Mexican restaurant)," Kareofelas says. "I take a square of toilet paper and fold it into a small square (3/4 of inch), dampen it and squeeze it so it is not sopping wet, just damp, and set the leaf and egg on the top. Put the lid tightly on the container. This keeps a level of moisture in the container. I check the containers daily, changing the toilet paper square to keep from molding."
The egg hatched. The caterpillar ate. And ate again, again and again. Did we mention "Again?" Again, again and again. She went through five instars, and then she j'd and formed a chrysalis on the ceiling of our indoor, netted butterfly habitat. The entire cycle from egg to larva to chrysalis to adult takes about a month. (See more on Bug Squad blog, Joy of Rearing Monarchs)
So Greta eclosed this morning, big, bold and beautiful. We released her in the pollinator garden, near where Mama deposited her as an egg. Greta inched up on a Mexican sunflower (Tithonia rotundiflora) and then took flight. A blur.
Hopefully, she will mate and overwinter in coastal California, avoiding the wildfires, adverse weather conditions and predators.
Safe travels, Greta! (And thank you, Greg!)
Unless it encounters a predator or parasitoid or another life-threatening factor, the egg will usually hatch 3 to 4 days after Mama Monarch deposits it beneath a milkweed leaf. As you know, monarchs lay their eggs only on milkweed, their host plant.
If you enjoy macro photography, it's a delight to photograph an egg with a highly specialized lens like the Canon MPE-65mm lens. Or you can observe the tiny egg with a magnifying glass or microscope.
How do you rear it?
Naturalist Greg Kareofelas, an associate of the Bohart Museum of Entomology at the University of California, does it this way:
"I put a single egg on its leaf in a small salsa container (the little plastic ones you would get at a Mexican restaurant). I take a square of toilet paper and fold it into a small square (3/4 of inch), dampen it and squeeze it so it is not sopping wet, just damp, and set the leaf and egg on the top. Put the lid tightly on the container. This keeps a level of moisture in the container. I check the containers daily, changing the toilet paper square to keep from molding."
"I raise the larva in that container until it gets big enough to move to a larger container. As long as you pay attention and check them often to make sure there is no mold or such, I have raised many this way successfully. The tight lid and slight moisture keeps the food plant fresher."
"You don't want loose water in the container, just enough so it is not dry," he says.
Among the many species of butterflies he's reared: the dogface butterfly or California state insect, Zerene eurydice; the Colias behrii, the Behr's sulphur or Sierra green sulfur; and the monarch, Danaus plexippus.
When our family rears monarchs, we usually begin with the caterpillars instead of the eggs. They're easier to find and collect. However, if you see a monarch laying her eggs, you know exactly where to look! Last weekend we watched a monarch deposit her eggs on our tropical milkweed, Asclepias curassavica, and our narrow-leaf milkweed, Asclepias fascicularis. We collected three eggs from the fascicularis and let the others be.
An adult monarch can lay about 400 eggs in her lifetime, Kareofelas says. Only a few survive due to predators and parasitoids and other factors. The major parasitoid in our garden is the tachinid fly which lays its eggs in or on the host or deposits its eggs on the milkweed leaves.
"If you start with the egg, the chance of it being parasitized is really small," says Kareofelas, who has been rearing butterflies most of his life, and especially for the last 15 years.
When the egg hatches into a larva or caterpillar, the 'cat will eat the eggshell first and then go about munching the milkweed. When it gets bigger, it's time to move it into a larger container. You must keep the milkweed fresh, as it can dry out quickly. Kareofelas likes to use water-filled floral tubes and dampened packing foam to keep the leaves/stems moist.
Our family's procedure to rear caterpillars: fill a heavy, wide-bottomed, narrow-necked tequila bottle with water, add sprigs of milkweed and the 'cats, and place in a zippered, net butterfly habitat. We place ours in our kitchen, a tachnid-free environment! Those tachnids can be sneaky! Also, replenish your milkweed and water daily, and remove the frass (excreta) daily.
It's a joy watching the complete metamorphosis, about a 30-day development from egg to larva to chrysalis to adult. The larval stage or caterpillar stage usually lasts 10 to 14 days, during which time the caterpillar will go through five instars (when it molts or sheds it skin). The 'cat will then form a "j" and pupate. The chrysalis stage lasts about 10 to 14 days, and voila! The familiar monarch icon ecloses and it's released back into the garden to start the cycle all over again.
Yes, it's a joy to watch them. But it's not a joy watching a tachnid-infested monarch caterpillar or a chrysalis. (We'd rather the tachnids lay their eggs in such pests as cabbage loopers or tomato hornworms.)
A good place to see butterfly specimens from all over the world is the Bohart Museum of Entomology (now temporarily closed due to the COVID-19 pandemic. Of the nearly eight million specimens in the Bohart, some 500,000 are in the Lepidoptera collection, curated by entomologist Jeff Smith. He and Kareofelas display and discuss the Lepidopterans during the open houses. In the meantime, watch the moth-butterfly videos on the Bohart Museum page.)
Which one is the most popular? Initially, it was the tropical milkweed, A. curassavica. We collected the first five caterpillars there. The A. fascicularis yielded the rest.
So, the count: narrowleaf milkweed, 11; tropical, 5; and showy, a no-show.
To date this year, we have released six monarchs back into the garden. The others went for university research. Elizabeth Pringle's laboratory at the University of Nevada, Reno, needed male and female monarchs to rear a colony, and the UC Davis laboratory of Louie Yang needed some tachinid flies.
Unfortunately for us--and fortunately for the Yang lab--tachinid flies infested two of our "11-piece collection." The adult flies are parasitoids that lay their eggs in immature monarchs (among other hosts). The fly larvae hatch and eat their host from the inside out. In a chrysalid, you can tell a tachnid fly infestation by the large tell-tale "dented" brown spot, it looks somewhat like a rotten spot on an apple. In a caterpillar? Think withered and discolored. Then a bungee-like white string appears, and the larvae (maggots) slide down--probably gleefully--like a kid on a Goliath Slide at the county fair.
Tachinids, however, are considered beneficial insects. They lay their eggs in or on such pests as cabbage loopers, cutworms, cabbage worms, gypsy moths, hornworms, harlequin bugs, lygus bugs, cucumber beetles, earwigs and the like. (See Bug Squad blog for close-up images of the tachinid larvae and pupae.)
2016: A Very Good Monarch Year
The year 2016 was a very good year for monarchs in our pollinator garden; we reared and released 60-plus. Sadly, the numbers fell drastically in 2017, 2018 and 2019. Last year, no eggs, no caterpillars and no chrysalids, and only a few monarchs passed through. In fact, in 2019 we did not see our first monarch until Aug. 9.
This year we're noticing a comeback of sorts. We spotted the first monarch on May 24. We now see:
- Males patrolling our yard and chasing the females--morning, noon and evening
- Females laying their eggs on the narrowleaf milkweed that's beneath the honeysuckle vine or the tropical milkweed that's beneath the roses
- Both males and females nectaring on milkweed, butterfly bush (Buddleia davidii), and Mexican sunflower (Tithonia rotundifolia), napping in the branches of the cherry laurels, and greeting any guests with flutter fanfare.
Life is good.
Sometimes the Gulf Fritillaries, Agraulis vanillae, that are hanging out on their host plant, the passionflower vine, mistake them for one of their own species and a pursuit begins.
Yes, the predators are out there: the California scrub jays, praying mantids, spiders, European paper wasps and yellow jackets. So are the tachinid flies and parasitoid wasps.
Would it be too much to ask them to...um....leave our monarchs alone? Yes.
Everybody eats in the garden. The menu choice is theirs.