Western tiger swallowtail (Papilio rutulus), Mayberry Park. June 30, 2015. Photo: K.McCutcheon.
“Most people are simply not aware of anything smaller than a robin; their senses are not adjusted to take in small wonders,” writes biologist Robert Pyle in Handbook for Butterfly Watchers. For those looking to gain appreciation for small wonders, learning to identify the Western tiger swallowtail is a great place to begin. Western tiger swallowtails are brightly colored (yellow with black stripes, like a tiger), active on warm sunny days during June and July (of which we have many), and among the largest (wingspan of 3 ¼ to 4 inches) and most common butterfly species found along the banks of the Truckee River. They are members of the Papillionidae, the Swallowtail family, a group of butterflies named for the long swallow-like “tails” on their hind-wings. Once you learn to recognize these butterflies, you may begin to notice them all over town.
The life cycle of the Western tiger swallowtail begins and ends near water, making the Truckee River corridor crucial habitat for these butterflies in our area. They use riparian plants (plants that grow near water) including willows, cottonwoods, aspen, alder and elm trees as host plants – plants where adults lay eggs and where caterpillars will feed (Garth & Tilden 1986). Most butterflies are very selective about host plants, and seek out their preferred species using taste receptors on their feet (Feltwell, 1986). As adults, Western Tiger Swallowtails feed on nectar from wildflowers that grow along the river, but also travel farther from the river to feed on flowers in parks and gardens (Garth & Tilden, 1986). Male swallowtails often congregate around mud puddles, likely gathering salts.
Similar species found in Washoe County include: Anise swallowtail, Indra swallowtail, Pale Swallowtail, and Two-tailed swallowtail (source: BAMONA database). A great place to learn more about our local butterflies is local non-profit Nevada Bugs and Butterflies.
References & Links:
Butterflies and Moths of North America. (2014). Papilio rutulus. http://www.butterfliesandmoths.org/species/Papilio-rutulus
Feltwell, J. 1986. The Natural History of Butterflies. New York, NY: Facts On File Publications.
Garth, J. S., & Tilden, J. W. (1986). California Butterflies (Vol. 51). (A. C. Smith, Ed.) Berkeley, CA: California Natural History Guides.
Pyle, R. M. (1984). Handbook for Butterfly Watchers. Boston, MA: Houghton Mifflin Company.
Shapiro, A. 2014. Papilio rutulus. http://butterfly.ucdavis.edu/butterfly/Papilio/rutulus