NATURE

A Dream Come True on Butterfly Wings

TIM WONG
Biologist Tim Wong models his favorite insect, the California pipeline swallowtail butterfly, which he has recolonized in San Francisco.
Meet the biologist who's been on a six-year mission to recolonize the pipevine swallowtail butterfly, native to San Francisco, back to the city's Botanical Garden

“Look up,” says Tim Wong, pointing to a concrete wall of the pump house in an out-of-the-way corner of the San Francisco Botanical Garden. What looks like leaf litter lodged on the textured wall, he says, is the chrysalis of a California pipevine swallowtail butterfly (Battus philenor hirsuta). The brown speck is something only trained eyes would see.

What is unmissable is the butterfly once it emerges from dormancy. Behold the pipevine swallowtail — a bright iridescent blue butterfly, four inches long, with orange spots on its underside. As Wong proudly points it out, it’s resting on a Ribes sanguineum, a native flowering currant, warming itself on the petite pink trumpet-shaped flowers that dangle from a branch.

Since 2012, Wong has made it his personal mission to recolonize this butterfly, native to San Francisco, back to the Botanical Garden. While common in other parts of Northern California, the pipevine swallowtail has been rare in the city for decades. “When I learned that,” Wong says, “I took it as a personal challenge.”

The 29-year-old has been raising butterflies since his kindergarten days in San Mateo County. His class raised painted ladies — one of the most common butterflies in North America — from kits. The metamorphosis from caterpillar to adult fascinated him. He asked his teacher where she bought the kits, and over the summer he had his parents buy him one and then another. While other kids his age were collecting baseball cards or playing video games, Wong grew butterflies.

TIM WONG
The life stages of the California pipevine swallowtail butterfly, from caterpillar to chrysalis to brightly colored butterfly. Biologist Tim Wong raises the butterflies at the San Francisco Botanical Garden.

Wong is fluent in animal. By day, he works as a biologist, caring for tropical invertebrates at the California Academy of Sciences. He makes sure the giant clams aren’t overcrowded by anemones in the coral reef gallery, feeds houseflies to devil’s flower mantises and tends to a paradise flying snake.

On his day off, he’s across the street, volunteering at the Botanical Garden, tending to his favorite of all spineless creatures — the butterfly. Most of the work improving the conditions for the butterflies involves cultivating a specific plant — the California pipevine (Aristolochia californica). If butterflies don’t have their host plant — where the females lay their eggs and young caterpillars feed — they can’t complete their life cycle.

Recolonizing the butterflies meant first improving their habitat by encouraging the California pipevine to thrive. Through patience and experimentation, Wong discovered that the vines thrive in full sun within city limits. He works with staff and volunteers to weed, remove invasive blackberry brambles and finesse conditions to be just right for the vine to thrive.

Wong’s efforts are paying off. In late spring and early summer, the butterflies emerge from chrysalises by the hundreds. “There are tornadoes of blue butterflies,” he says. Slow-moving caterpillars line the garden’s walking paths. Last year, Wong experimented with “Caterpillar Crossing” signs to alert adults and teens glued to their phones. Little kids, he says, spot the caterpillars right away, crouching down to get a closer look. Maybe one among them will be the next to get inspired and learn that a successful conservation effort can start with a single bug.

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