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Lomatiums are Larval Host Plants for the Anise Swallowtail Butterfly

Anise swallowtail butterflies (Papilio zelicaon) are a welcome sight in the Klamath-Siskiyou in the summer. These large and showy butterflies are not only beautiful, but they are also pollinators that perform an ecological service. Although these beauties are common, it is always a treat to observe one as it nectars on flowers and flutters about. Unlike the well-known monarch butterfly that migrates each winter, swallowtail butterflies do not migrate. Instead, they form chrysalids in early fall which overwinter in protected places until emerging in the spring. As I write this post anise swallowtail butterflies have begun to emerge and be seen around the Klamath-Siskiyou.
Lomatium macrocarpum4
Bigseed biscuitroot (Lomatium macrocarpum) is a small plant found in exposed, rocky areas
Anise swallowtail butterflies use larval host plants in the family Apiaceae. In the Klamath-Siskiyou this includes Lomatium species, which go by common names such as desert parsley, buscuitroot, wild parsley, Indian parsnip, or just plain lomatium.
Anise swallowtail butterfly early instar caterpillar feeding on garden parsley
The name of the anise swallowtail butterfly came from the fact that, as its native habitat has diminished, it has adapted to using non-native fennel — sometimes referred to as wild anise — as a larval host plant. It will also use carrots, parsley and parsnips in a vegetable garden, so keep an eye out. I had about fifteen anise swallowtail butterfly caterpillars on parsley and parsnip plants in my garden last summer. It’s too bad this butterfly species wasn’t called the lomatium butterfly instead, in order to highlight it’s native larval host plant. Lomatiums also provide habitat for all kinds of other pollinators and insects, including spiders, beetles, flies, bees and more.
This past summer I was lucky to find and observe numerous anise swallowtail butterfly chrysalids that developed from the caterpillars feeding on parsley and parsnips in my garden, including this chrysalis that I found on the eve of my house while cleaning my gutters.
The lifecycle of anise swallowtail butterflies is different in different ecotypes. At the McLaughlin Natural Reserve in California they have observed the following: “Anise Swallowtail (Papilio zelicaon) is common throughout the western United States, and feeds on plants in the carrot family including the invasive fennel (Foeniculum vulgare). Populations on serpentine, such as those at the reserve, feed on serpentine endemic species of Lomatium. In most of its range the Anise Swallowtail is capable of undergoing more than one generation per year, but populations on serpentine may be genetically limited to a single brood per year. The pupae in serpentine populations may even remain dormant for several years before metamorphosing into adults; this is likely an adaptation to a harsh and fluctuating environment, just like seed dormancy in plants.”
Anise swallowtail butterfly caterpillar everting its osmeterium, or “stinkhorn.”
As a defense mechanism anise swallowtail caterpillars have an unusal feature: osmeterium or “stinkhorns.” Home Ground Habitat Nursery (which has a great write-up on swallowtail butterflies by the way!) describes it this way: “The osmeterium is an eversible organ, concealed in a slit behind the head. If the larva is disturbed it everts the bright orange-colored osmeterium, and discharges a foul scent. The scent the larvae discharges upon eversion of its osmeterium comes from a secondary biochemical compound produced by a number of plants in the carrot family (Apiaceae). The biochemical compound is not essential to the life of the plant; but necessary to elicit feeding by the larvae. The osmeterium is just one of the defenses against visual predators; in the case of birds, most of which do not have a highly developed sense of smell, it might be more the startling effect of a sudden change to the form of the larvae that affords some protection.” In addition to be a larval host plant for anise swallowtails, and habitat for a whole host of other beneficial pollinators and insects, lomatiums are also amazing medicinal plants for people! What’s not to love about lomatiums? In Michael Moore’s classic book, Medicinal Plants of the Pacific West, he writes the following about lomatium: “Lomatium has been used for centuries as a medicine by Native Americans who live in the Great Basin; it was used by many Mormon settlers in Utah and Nevada, and it was well known by some Oregon pioneers. They all used it for lung problems, bad fevers, and pneumonia, and there are many references to its value for persistent winter fevers…Further, several of the aromatics have been shown to limit replication or shedding in many viruses, and they also seem to shorten the duration of the viral infection and limit the surface area of mucus membranes that become infected.”
Common Lomatiums of the Klamath-Siskiyou: Large
  • Lomatium californicum — up to 4′ tall and usually found growing on wooded or brushy slopes, in open grassy areas, or in upland prairie.
  • Lomatium dissectum — up to 4′ tall and usually found growing on wooded or brushy slopes, in open grassy areas, or in upland prairie.
  • Lomatium triternatum — up to 3′ tall and usually found on open slopes and in pine woodland.
  • Lomatium nudicaule — 1′-2’tall and usually found on rocky slopes, flats, brushy areas, and generally pine woodland.
  • Lomatium macrocarpum — 4″- 1.5’tall and found in rocky openings within forests and has an affinity to serpentine soil.
  • Lomatium urticulatum — 4″- 1.5′ tall and found in open grassy slopes, meadows and woodland.
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