- Author: Kathy Keatley Garvey
You gotta love those 'cats.
Gulf Fritillary caterpillars (Agraulis vanillae) are always hungry. They're as hungry as teenagers returning home from a marathon swimming meet or from a double-overtime basketball game. As soon as they step in the front door, it's off to the refrigerator. What's to eat? I'm starving! When's dinner?
Gulf Frit caterpillars are like starving teens. The 'cats will eat everything in sight--the leaves, buds, flowers and stems of their host plant, the passionflower vine (Passiflora). "Host plant" is a good word--you be the host, Passiflora, and we, the Gulf Frits, will eat it all. Everything.
In fact, Gulf Frit caterpillars will compete for food and knock one another around. When food is scare, they'll engage in a little cannibalism.
If you have a healthy passionflower vine and a good supply of Gulf Frits, chances are your plant will be skeletonized by the end of the season. The 'cats will eat heartily, form a "J," spin into a chrysalis, and voila! An adult butterfly will eclose. That's what butterflies do.
In a previous Bug Squad, we mentioned that the Gulf Frits are found in many parts of the world and arrived in California (San Diego) in the 1870s, according to butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology. They spread through Southern California in urban settings and were first recorded in the Bay Area about 1908, Shapiro says. They "became a persistent breeding resident in the East and South Bay in the 1950s and has been there since.”
Shapiro says the Gulf Frits “apparently bred in the Sacramento area and possibly in Davis in the 1960s, becoming extinct in the early 1970s, then recolonizing again throughout the area since 2000.”
Some folks don't like Gulf Frits skeletonizing their passionflower vines. They grow them for the passion fruit and for their floral beauty. And when the Gulf Frits take over and decimate the plants? "We look like bad gardeners," lamented one UC Master Gardener.
Bad gardeners? Well, no. Good butterfly conservationists? Yes!
- Author: Kathy Keatley Garvey
Sex. Passion. Passionflower vine.
And by--what else--the "passion butterflies," Gulf Fritillaries (Agraulis vanillae).
We came across the scenario below by accident. We were watching a Western scrub jay (now known as a California scrub jay, Aphelocoma californica) methodically fly over to the passionflower vine (Passiflora), perch on the fence, and dine on multiple caterpillars. See, the scrub jays are nesting in our cherry laurels, and the Passiflora is their supermarket for "grocery" selection, checkout, and take home.
For the last several weeks, the scrub jays have been pigging out like human celebrants at a Thanksgiving feast. Yes, birds can pig out, too. As predators, the jays have dominated and overpowered the vine and snagged almost all of our caterpillars...caterpillars that were just trying to become butterflies.
Then three things happened: (1) Hawks appeared in the neighborhood (2) Western scrub jays began vanishing and (3) the triple-digit weather set in, with dozens of Gulf Frits gathering on the Passiflora. It became a bedroom and nursery of sorts. The jays' supermarket wasn't so "super" anymore. More hawks. Fewer jays. More eggs, caterpillars and chrysalids.
Like many butterfly aficionados, we welcome the orangish-reddish butterfly with silver-spangled underwings. It is as spectacular as it is showy.
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, has been monitoring the Gulf Frits and other butterflies in Central California (see his website) for more than four decades.
The butterfly, found in many parts of the world, was first documented in Southern California in the 1870s, according to Shapiro.
"It first appeared in the vicinity of San Diego in the 1870s,” he says. “It spread through Southern California in urban settings and was first recorded in the Bay Area about 1908. It became a persistent breeding resident in the East and South Bay in the 1950s and has been there since.”
Shapiro says it “apparently bred in the Sacramento area and possibly in Davis in the 1960s, becoming extinct in the early 1970s, then recolonizing again throughout the area since 2000.”
The history of the scientific name of the species is fascinating. Vanillae? That was an error traced back to German-born naturalist and scientific illustrator Maria Sibylla Merian (1647-1717). She knew butterflies--she reared them--but she took some artistic liberties.
Merian drew the Gulf Frit on a vanilla orchid, and scientists assumed that this was the host plant. Not so. The host plant is Passiflora. "Johannes Fabricius knew that the bug eats Passiflora and tried to rename it passiflorae," wrote Shapiro in a 2008 edition of the Journal of the Lepitoperists Society. It didn't take.
So Agraulis vanillae it is.
- Author: Kathy Keatley Garvey
It's an incredible photo.
Nicole "Nikki" Nicola, a staff research associate in the Frank Zalom lab in the UC Davis Department of Entomology and Nematology, University California, Davis, captured an image in her back yard of both the male and female Valley carpenter bee (Xylocopa varipuncta) sharing the same passionflower (Passiflora).
Most of us often see--and hear--the solid black female, but not so much the green-eyed blond male. And rarely together.
But to see them on the same flower? What a great example of sexual dimorphism!
Amazing.
Nicola works with Zalom, an integrated pest management specialist and distinguished professor of entomology. A noted entomologist, he is a past president of the 7000-member Entomological Society of America.
As for those Valley carpenter bees, the next time you see the female frequenting the Passiflora, check out those tiny grains of golden pollen. They look for all the world like gold dust.
Valley carpenter bees are found in the Central Valley and southern California, Arizona, New Mexico and southward through Mexico, according to native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at UC Davis.
- Author: Kathy Keatley Garvey
Nature isn't perfect, but neither are we!
Today we watched a Gulf Fritillary (Agraulis vanillae) laying eggs on her host plant, the passionflower vine (Passiflora) and another Gulf Fritillary nectaring on the nearby Jupiter's Beard (Centranthus ruber). Ms. Gulf Frit looked quite discolored; she wasn't that showy orange butterfly that we're accustomed to seeing, but she was a good egg layer. She deposited eggs all over the Passiflora within a five-minute time spanm and then returned to lay more eggs.
A warm springlike day. A perfect day. A not-so-perfect butterfly.
Butterfly guru Art Shapiro, distinguished professor of evolution and ecology at UC Davis who has studied the butterfly population in Central California for more than four decades (see his website) says that the discoloration is "probably developmental rather than genetic."
"Rear some eggs," he says, and "see if anything odd results. These depigmentized bugs are seldom so symmetrical. Under a scope the depigmentized scales may be curly."
Time to rear some eggs and see what develops!
(Editor's Note: The UC Food Observer blog today featured Bug Squad. We are humbled!)
- Author: Kathy Keatley Garvey
It's a predatory world out there.
Newly emerged Gulf Fritillaries (Agraulis vanillae) are fluttering around the yard--nectaring on lantana, finding mates, mating, and trying to avoid predators. The females are laying tiny yellow eggs on their host plant (Passiflora). Soon we'll see caterpillars and chrysalids and more Gulf Frits.
Every stage may be the end. A Western scrub jay may snatch a Gulf Frit adult in flight; wasps, lady beetles and spiders will devour the caterpillar eggs; and parasitoids and wasps will attack the caterpillars and chrysalids. Over the years we've watched scores of Western scrub jays dining on the caterpillars (ah, worms!) and feed them to their young, and European paper wasps and praying mantids targeting caterpillars and butterflies.
The predator-prey episodes usually involve six steps: encounter, detection, interaction, attack, capture and kill.
Nature's way.
If you look closely, the wings of the survivors tell the story. Pristine? Newly emerged and untouched. Ripped and torn? A predator encounter.