It's commonly called a "passion butterfly," but we call it a Gulf Fritillary (Agraulis vanillaea) or Gulf Frit.

Or "spectacular."

A sure sign of autumn:

• A skeletonized passionflower vine (Passiflora)
• A Gulf Fritillary (Agraulis vanillae) eclosing
• A ravenous caterpillar crawling along a stem, and
• A caterpillar J'ing, about to form a chrysalis.

The orange-reddish butterfly, with its silver-spangled underwings, is a glorious butterfly.

How's the population doing this year?

Butterfly guru Art Shapiro, UC Davis professor of evolution and ecology, who has monitored the butterfly populations of central California for more than four decades and posts his research on Art's Butterfly World, says this year the Gulf Frit population is "spotty; locally abundant but less generally distributed than in recent years."

His 10 field sites stretch from the Sacramento River Delta through the Sacramento Valley and Sierra Nevada mountains to the high desert of the Western Great Basin.

We notice the ups and downs of the Gulf Frit population every year in Vacaville. This spring they were slow to start, Western scrub jays and European paper wasps grabbed what few caterpillars there were. In the summer, the population speeded up.  And now caterpillars and chrysalids cover two of our three vines--or what's left of our three vines.

Shaprio says the Gulf Frit was introduced into southern California in the 19th century, in the vicinity of San Diego in the 1870s. It was first recorded in the Bay Area before 1908. "It became a persistent breeding resident in the East and South Bay in the 1950s and has been there since." Once prevalent in the Sacramento area in the 1960s, it "seems to have died out by the early 1970s," he said.  Then in 2009, it began making a comeback in the Sacramento area.

Meanwhile, the passionflower vine climbs our fences with reckless abandon, only to be skeletonized by the growing population of Gulf Frits. They eat the leaves, the flowers, the fruit, and then start in on the bark.

More Gulf Frits mate. More eggs, caterpillars, chrysalids and adults appear. The cycle continues until the first frost. The plants die back, and will recover in the spring. A few chrysalids will remain, clinging to the vines like leftover Christmas tree ornaments,

Surprises occur. Several years ago, we saw a Gulf Frit laying an egg on Christmas Day.

Today was a Monarch Kind of Day...in Vacaville.

When Art Shapiro, UC Davis distinguished professor of evolution and ecology, searched for butterfly species today at one of his field sites--Gates Canyon in Vacaville--he spotted not one, but two monarchs.

He spotted them separately, both near the bottom of the Brazelton property, and recorded "Two Danaus plexippus: one large, fresh-looking male; one small, unfresh-looking female."

Shapiro, who maintains a research website, Art's Butterfly World (he's monitored the butterfly population in central California since 1972), knows just how scarce monarchs are this year.

Yes, they are. In the fall of 2016, we'd see seven or eight monarchs at a time flutter in for nectar or lay eggs on our milkweed in our Vacaville pollinator garden. This year they're as scarce as the proverbial hen's teeth.  However, over the last two weeks, they're starting to appear, one sighting at a time, one monarch a day. They are mostly huge, fresh-looking males seeking nectar from our patch of Mexican sunflowers (Tithonia). A few are females that head over to the tropical milkweed or Tithonia. Solo sightings.

But today was a Monarch Kind of Day.

Around noon, two monarchs arrived at the same time and they both sipped nectar from the Tithonia at the same time. In tandem. Inches away.

It was a Monarch Kind of Day.

What are the odds?

Here you are, standing in the garden section of a home improvement store, and you select a tropical milkweed to purchase. You place it on the ground and admire the brilliant yellow blossoms and luxurious green foliage. It's the best of the best. Just as you're about to pick it up and place it in a cart, a monarch lands on it and begins laying eggs.

What are the odds?

That happened to us around Wednesday noon, Sept. 4 in Vacaville as we were purchasing an end-of-the-season Asclepias curassavica.

Most likely, the plant had been in the nursery since last spring, as it was root-bound. We took it home, replanted it in a larger pot, and set it in the sun. Milkweeds like full sun. And monarchs go where their host plant is, whether it be in the wild, in your backyard, in your city park, or in a garden section of your local home improvement store.

Hopefully, the monarch eggs will hatch and this tropical milkweed will yield some caterpillars, chrysalids and adults.

Monarch egg. (Photo by Kathy Keatley Garvey)

Ironically, we found a monarch laying eggs in the garden section of a home improvement store!

Said entomologist David James of Washington State University, Pullman, who researches migratory monarchs: "That's an amazing story...selecting your milkweed and then having a female come over and deposit a few eggs for you!"

As an aside, as we were purchasing the milkweed, I casually asked the clerk at the check-out line "Have you seen any monarchs here?"

"Not in HERE," she said, surprised I would ask such a question. She tallied up the sale as "Mama Monarch" fluttered around her nursery, unnoticed, laying the next generation.

Curiously enough, a family member recorded a monarch laying eggs in the garden section of that same store the day before. About the same time. Maybe the same monarch. (See YouTube video)

Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, who has monitored all butterfly populations in the central valley for more than four decades and publishes his research on a website, says that “this is the biggest milkweed year in northern and central California in living memory. Speciosa is up to 5' tall and some fascicularis almost as big, and both are covered with both genera of Lygaeids (milkweed bugs), plus both oleander and gray aphids. But Monarchs only showed up here about two weeks ago! Lots of milkweed, no Monarchs to use it. I have seen 10 Monarchs in 2019 and have not seen a wild larva since 2017, and I am afield 260 days a year.”

Sometimes life just isn't fair. Entomologist Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, commented “Weirder and weirder. They still haven't found MY milkweed.”    

If you've ever reared a butterfly--from an egg to a caterpillar to a chrysalis to an adult--you know what it feels like.

Like a miracle, to see life unfolding.

Our friend, Marilyn Sexton, aka "Anise Swallowtail Butterfly Mama," showed us her Bohart Museum of Entomology habitat that housed two remaining adult butterflies ready to be freed.

It was a beautiful day in the neighborhood, as Mr. Rogers (Fred Rogers, 1928-2003) sang.

Two glorious butterflies, Papilio zelicaon, burst out of their habitat and headed straight for some rich floral nectar. 

It's a common swallowtail butterfly of western North America, and often confused with the Western tiger swallowtail, Papilio rutulus, also in the same range.

Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, who has monitored butterfly populations in Central California since 1972, says on his website:

"The anise swallowtail is a complex set of ecological races, or 'ecotypes,' whose seasonality has been adjusted by natural selection to match that of their host plants. Selection for adaptive life-history traits seems to have proceeded much faster than evolution at the level of neutral molecular loci.

"At sea level our populations are strongly multivoltine, with only weak, facultative pupal diapause. They have several generations (late February or March-October) and breed very largely on sweet fennel ('anise'), Foeniculum vulgare, and (in the first half of the season) poison hemlock, Conium maculatum. Both of these are naturalized European weeds."

Weeds or not, butterflies or not, anise swallowtails are spectacular.

Yes, 'twas a beautiful day in the neighborhood...