Animal Diversity Web

Geographic Range

Euphydryas editha can be found in scattered, semi-isolated populations in the western United States. Coastal populations range from southern California to western Washington. The species can also be found in locations of the San Bernardino Mountains, Sierra Nevada, higher Cascade Mountains of Oregon to Washington, and in areas of the Great Basin, including central Oregon and the Rocky Mountains. (Radtkey and Singer, April 1995; Scott, 1986)

• Biogeographic Regions
• nearctic
  • native

Habitat

Edith's checkerspot prefer grasslands and rocky outcrops found in the mountains. They are usually found in areas of nutrient-poor, serpentinitic soils which sustain the native grasslands that they prefer. (Baughman, August 1991; Scott, 1986; Thomas, et al., December 1996; Weiss, 1999)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• mountains

Physical Description

Euphydryas editha butterflies are usually orange with checkerboard markings; however, their appearance varies based on the area that they inhabit. Coastal populations are black with red and cream spots; mountain populations are red or mottled with red, black, and cream spots. The higher-altitude populations are smaller and darker in color. The larvae of the butterfly are black, spotted with white or orange, or striped with white. The pupae are white or gray, with black blotches and streaks. (Cohen, August 31, 1996; Scott, 1986)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

Development

Euphydryas editha eggs hatch about two weeks after they are laid. Larvae live and feed together in loose silk webs, complete three instars, and enter diapause during the spring. Edith's checkerspot larvae have thick and hairy skins to better withstand summer drying during diapause, and can usually be found under stones as they hibernate. The larvae emerge from diapause the following spring, complete development, and pupate. (Osborne and Redak, January 2000; Scott, 1986; Thomas, et al., December 1996)

• Development - Life Cycle
• metamorphosis
• diapause

Reproduction

Once a male spots a resting female, the male lands, nudges under the female's hind wings, and mates with the female, if receptive. A receptive female is passive, while an unreceptive female will reject advances made by males by flapping or trying to escape. (Scott, 1986)

Euphydryas editha are protandrous - males typically emerge four to eight days prior to the emergence of females. The females are able to mate and lay eggs immediately upon emergence from the pupa. Females generally mate once, but are physiologically capable of re-mating four to seven days after their first copulation. Most do not re-mate, however, partly because the male's spermatophore plugs the female's mating tube at least temporarily, and partly because ovipositing females are not attractive to males. Only virgins secrete a pheromone that attracts males. Checkerspot butterflies are univoltine, meaning one generation reaches maturity per year. The eggs are laid in clusters of 20 to 350, and up to 1200 eggs are laid per female lifetime. (Baughman, August 1991; Scott, 1986; Thomas, et al., December 1996)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• oviparous

• Breeding season

  spring (flight season)

• Range eggs per season

  20 to 350

• Average gestation period

  12 months

Once eggs are laid, there is no parental involvement in this species.

• Parental Investment
• pre-fertilization
  • provisioning

Lifespan/Longevity

Adult Edith's Checkerspot live about ten days, on average.

(Baughman 1991)

Behavior

Euphydryas editha are very sedentary - individuals do not move more than 600 meters, or 2000 feet, in their entire lifespan. Perhaps because of this, there are many phenotypically well-defined groups that rise from preferences for different combinations of host plants existing in close proximity of one another. Very little gene flow occurs between these populations. Adults make one flight during March to April on the California coast, June in the Great Basin, and late June to early August above the timberline. (Britten, et al., 1995; Sbordoni and Forestiero, 1998; Scott, 1986)

• Key Behaviors
• flies
• sedentary
• hibernation

Communication and Perception

Checkerspots are known to communicate at least on the chemical level. Virgin females release a pheromone which attracts males, allowing them to be located in order to mate. Unseen virgins are typically found by a male after about an average of fifty minutes. Males also contact females prior to copulation. (Scott, 1986)

• Communication Channels
• tactile
• chemical

• Other Communication Modes
• pheromones

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Edith's checkerspots prefer herb host plants from the families Scrophulariaceae, Valerianaceae, Plantaginaceae, and Caprifoliaceae. However, most populations of this butterfly are monophagous, and the preference is based on location. Egg-laying habits, larval host preference, and movements are locally adapted, and for that reason, the survival of Euphydryas editha depends upon the growing season of its host plants. The differences in host preferences are genetically based. Diet evolution in Euphydryas editha can be very rapid. Adult butterflies seek nectar and seem to prefer yellow or white flowers. The host plant flowers are never visited, apparently because the butterfly's proboscis is too short. (Cohen, August 31, 1996; Osborne and Redak, January 2000; Radtkey and Singer, April 1995; Scott, 1986)

• Primary Diet
• herbivore
  • folivore
  • nectarivore

• Plant Foods
• leaves
• nectar
• flowers

Predation

Checkerspot butterflies have developed defense mechanisms to prevent predators from attacking. Larvae twitch in unison to repel predators, and, depending on the host plant of the population, the larvae, pupae, and adult butterflies are somewhat poisonous to vertebrates because they may injest toxins from the plant. (Scott, 1986)

Ecosystem Roles

Populations of Euphydryas editha use several different hosts to house and feed their pupae. Though they usually do not pollinate the flowers of the host, larvae have been known to eat the leaves, the flowers, and sometimes the entire host plant, and have starved trying to find another. (Radtkey and Singer, April 1995; Scott, 1986; Thomas, et al., December 1996)

• Ecosystem Impact
• pollinates

Economic Importance for Humans: Positive

In order to obtain nectar, adult Euphydryas editha sometimes pollinate various flowers in the area of their habitat. (Scott, 1986)

Economic Importance for Humans: Negative

Edith's checkerspots lay their eggs on various plant species, sometimes resulting in the death of the host plant, which could be economically important to humans.

Larvae, pupae, and adults are poisonous to vertebrates if ingested. (Scott, 1986)

Conservation Status

Euphydryas editha populations mirror the changes in climate over long periods of time. Global warming is expected to eliminate the butterflies in the south, where the season is short and growing shorter. About three-fourths of the populations living in the lowest latitudes have become extinct. In Canada, however, less than twenty percent have disappeared. The sedentary checkerspots remain at their original habitat despite human interferences, and evolve adaptations to deal with these changes, thus making them dependent on the continuation of the human interference. This dependency results in insects that refuse to accept their ancestral host. In January of 1997, the subspecies Euphydryas editha quino and Euphydryas editha bayensis received federal protection under the Endangered Species Act. Euphydryas editha bayensis has also been given the Nature Conservancy Global rank of T1, which means that there are very few individuals remaining. (Cohen, August 31, 1996; Osborne and Redak, January 2000; Singer, et al., December 16, 1993; Struttmann, 2004)

• IUCN Red List

  No special status

• US Federal List

  Endangered

• CITES

  No special status

Other Comments

In the past thirty years, Edith's checkerspots have suffered two major crises. In 1967, humans cut down patches of a forest inhabited by the butterflies. The butterflies were able to adapt, and began to lay eggs on a new host with a high rate of breeding success. In 1992, a severe summer frost killed the new host, and checkerspot larvae starved. At least 21 subspecies of Euphydryas editha exist. (Miller, 1992; Thomas, et al., December 1996)

Contributors

Matthew Wund (editor), University of Michigan-Ann Arbor.

Joleen Kayanickupuram (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

References

Baughman, J. August 1991. Do Protandrous Males Have Increased Mating Success? The Case of *Euphydryas editha*. The American Naturalist, Vol. 138, No. 2: 536-542.

Britten, H., P. Brussard, D. Murphy, P. Ehrlich. 1995. A Test for Isolation-by-Distance in Central Rocky Mountain and Great Basin Populations of Edith's Checkerspot Butterfly (*Euphydryas editha*). The Journal of Heredity, Vol. 86, No. 3: 204-210.

Cohen, P. August 31, 1996. Edith's Butterfly Flees North. New Scientist, Vol. 151, Issue 2045: 9.

Miller, J. 1992. The Common Names of North American Butterflies. Washington & London: Smithsonian Institution Press.

Osborne, K., R. Redak. January 2000. Microhabitat Conditions Associated with the Distribution of Postdiapause Larvae of *Euphydryas editha quino* (Lepidoptera: Nymphalidae). Annals of the Entomological Society of America, Vol. 93, No. 1: 110-114.

Radtkey, R., M. Singer. April 1995. Repeated Reversals of Host-Preference Evolution in a Specialist Insect Herbivore. Evolution, Vol. 49, Issue 2: 351-359.

Sbordoni, V., S. Forestiero. 1998. Butterflies of the World. Ontario, Canada: Firefly Books.

Scott, J. 1986. The Butterflies of North America, A Natural History and Field Guide. Stanford, California: Stanford University Press.

Singer, M., C. Thomas, C. Parmesan. December 16, 1993. Rapid Human-Induced Evolution of Insect-Host Associations. Nature, Vol. 366: 681-683.

Struttmann, J. 2004. "Butterflies of North America:Butterflies of Washington" (On-line). Accessed 12/14/04 at http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/wa/170.htm.

Thomas, C., M. Singer, D. Boughton. December 1996. Catastrophic Extinction of Population Sources in a Butterfly Metapopulation. The American Naturalist, Vol. 148, No. 6: 957-975.

Weiss, S. 1999. Cars, Cows, and Checkerspot Butterflies: Nitrogen Deposition and Management of Nutrient-Poor Grasslands for a Threatened Species. Conservation Biology, Vol. 13, No. 6: 1476-1486.