Where are the monarch butterflies? They're MIA on the four species of milkweed in our Vacaville pollinator garden
But milkweed attracts other insects, including honey bees, carpenter bees, bumble bees, assassin bugs, syrphid flies, leafcutter bees, Anthophora (genus) bees, wasps, praying mantids, and butterflies, including Gulf Fritillaries, Agraulis vanillae, and gray hairstreaks, Strymon melinus. And yes, arthropods such as crab spiders and orbweavers visit, too.
On Sept. 19, we witnessed a gray hairstreak laying eggs on the buds of a tropical milkweed, Asclepias curassavica, which we planted in a container with another milkweed, butterflyweed, A. tuberosa. (Yes, we give the monarchs a choice; we also offer them showy milkweed, A. speciosa, and narrowleaf milkweed, A. fascicularis, and we cut back the A. curassavica before the fall migration, as noted entomologists recommend.)
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, says this about the gray hairstreak on his website, Art Shapiro's Butterfly Site:
"This is one of the most polyphagous butterflies known, recorded on host plants in many families. Its most frequent hosts in our area are mallows, including the weedy species of Malva; legumes, including Spanish Lotus (Lotus purshianus), Bird's-Foot Trefoil (Lotus corniculatus), White Clover (Trifolium repens) in lawns, Alfalfa (Medicago sativa) and many others;and Turkey Mullein (Eremocarpus or Croton setigerus, Euphorbiaceae)."
So, we mentioned the gray hairstreak laying eggs on the buds of the milkweed. "Is this a host plant, too?"
"Apparently on the flower buds! Never before recorded--in fact, I have no records on Asclepiadaceae/Apocynaceae at all," Shapiro said. "They lay on Callistemon (bottlebrush) too..."
Meanwhile, update: no monarchs, no eggs. We're still waiting.
But "yes" on the gray hairstreak, Strymon melinus, and "yes" on her eggs.
Oh, to be a praying mantis, and hide among the flowers waiting for prey.
On a warm sunny morning in Vacaville, Calif., this female Stagmomantis limbata positioned herself in a patch of Mexican sunflowers, Tithonia rotundifola.
She lurked beneath a blossom, camouflaged with the green leaves and stems. She groomed herself. It's important to wash up before breakfast and be presentable at the breakfast table and say your prayers.
Then she spotted a honey bee.
Ms. Mantis climbed the stem and peered over the orange petals.
What happened next? Spoiler alert, no breakfast for Ms. Mantis.
Later, though, another mantis hanging out in a nearby rosebush snagged and ate a small fly and a slow milkweed bug. Satiated, she crawled beneath a leaf, perhaps to digest her breakfast and sleep. You could say she "rose" to the occasion, or you could just say she was hungry.
You want to let Big Red to stay in.
This male flameskimmer hung out in our pollinator garden in Vacaville on July 3 for a little over five hours. He perched on a bamboo stake, periodically circled to grab a few bees, and then returned to his post to eat them.
Flameskimmers, Libellula saturata, are a joy to watch as they circle, curve and dip to snatch their prey in flight. When they perch, they sometimes look like a biplane.
If you love dragonflies, note that the Bohart Museum of Entomology created an educational poster, "Dragonflies of California," the work of then doctoral candidate Fran Keller (now a professor at Folsom Lake College) and naturalist/photographer Greg Kareofelas of Davis. It focuses on 18 dragonflies commonly found in the Golden State. Keller is now a professor at Folsom Lake College. The Bohart Museum, home of nearly eight million insect specimens, is temporarily closed to the public due to COVID-19 pandemic precautions but the gift shop is online.
Kareofelas identified this flameskimmer as a male.
After an afternoon sunning and dining in our garden, Big Red left for parts unknown.
He was back today to stake out his claim and snatch a few more bees (in this case, Melissodes agilis and Svastra obliqua expurgata). Table for one? He needs no reservations, no menu and no wait staff.
It was July 3, 2020.
The male bees, Melissodes agilis, were getting quite territorial.
Every time a butterfly, a honey bee or another insect in our family's pollinator garden expressed an interest in foraging on the Mexican sunflowers, Tithonia rotundifola, a male Melissodes buzzed them.
"Get out of here!" he threatened. "I own these flowers. These are mine!"
What to do? I grabbed my Nikon D500 and 200 mm macro lens, adjusted the settings to 1/5000 of a second, f-stop 5.6, ISO of 800, and managed to get a shot of the menacing bee confronting a bewildered monarch.
Eye-to-eye. Antenna-to-antenna. Wing-to-wing.
What happened? The monarch quickly escaped the wrath.
And the bee? It buzzed off, only to return to target another insect.
"Get out of here! I own these flowers. These are mine!"
Another tiff on the Tithonia. Another round on the rotundifola.
Just another day in the pollinator garden.
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.