He researched the butterfly and learned that when in caterpillar form, it only feeds on one plant: the California pipevine (Aristolochia californica), an equivalently rare flora in the city.My own butterfly conservation efforts, alas, are not such a success. I read somewhere that the best thing anyone could do to help monarch butterflies is to plant milkweed in your garden. So when a milkweed plant randomly sprouted under my kids' swingset, I transplanted it to the flower garden. There is has thrived and multiplied and become one of my worst weeds. And though I occasionally see a monarch in the garden, usually late in the summer, none have ever laid eggs.
"Finally, I was able to find this plant in the San Francisco Botanical Garden [in Golden Gate Park]," Wong says. "And they allowed me to take a few clippings of the plant."
Then in his own backyard, using self-taught techniques, he created a butterfly paradise.
"[I built] a large screen enclosure to protect the butterflies and to allow them to mate under outdoor environmental conditions — natural sun, airflow, temp fluctuations," he says.
"The specialized enclosure protects the butterflies from some predators, increases mating opportunities, and serves as a study environment to better understand the criteria female butterflies are looking for in their ideal host plant."
Every summer my garden is completely overrrun with swallowtails, sometimes a dozen at a time. Thinking it would be fun for me kids to see the caterpillars, I planted some fennel, which is one of the plants they like. In my old garden I planted fennel and it ended up mostly eaten by caterpillars. But in my new house, the flocks of swallowtails find my fennel completely uninteresting – not a single egg, not a single boldly striped caterpillar. Sigh.