Icaricia icarioides missionensis

Overview

Formerly relatively widespread on the San Francisco and Marin peninsulas in California, the mission blue is now restricted to only a few sites. On San Bruno Mountain, in San Mateo County, 2000 acres of habitat for the butterfly are being managed by the county department of Parks and Recreation. A habitat conservation plan was also developed for rare butterflies, including the mission blue, at San Bruno Mountain. Revisions will include the newly discovered colonies. Much of the habitat the mission blue occurs on private lands that have been planned as housing developments in the City of Pacifica General Plan.

Preservation of existing butterfly populations relies on many factors common to butterfly conservation programs: replanting of host plants, removal of introduced plants, and protection from excessive recreational use and development.

Description

The mission blue (Icaricia icarioides missionensis) is a small butterfly in the Lycaenidae (gossamer wing) family. Wingspan is about 1 to 1.5 inch (2.5-3 cm). The dorsal wing surfaces of the male are iridescent blue and lavender with black margins fringed with long white hair-like scales. There are no spots on the upper surfaces of the wings. In males, the ventral surfaces of the wings are whitish with small circular gray spots in the submarginal areas and larger circular black spots located in post-median and submedian areas of the fore and hind wings. The body of the male is dark bluish brown. Females have dark brown dorsal wing surfaces marked with blue basal areas. The margins and wing fringe are similar to the male. Female ventral wings are stone gray with a dot pattern similar to the males.

Life History

The adult flight season extends from late March to early July, depending on the location and microclimatic conditions. The adults feed on hairy false goldaster (Heterotheca villosa), bluedick (Dichelostemma capitatum), and seaside buckwheat (Eriogonum latifolium), and do not wander far from the three species of lupine that are the larval food plant. These species are silver lupine (Lupinus albifrons), summer lupine (L. formosus), and manycolored lupine (L. versicolor). Females lay eggs throughout the mating flight. The eggs are laid singly on leaves, stems, flowers and seed pods of lupine species.

Eggs hatch 4-7 days after being deposited. Young larvae feed on the inner tissues of the host plant leaves. After feeding, the small second instar larvae enter diapause in the litter at the base of the host plant. Larvae emerge from diapause and resume feeding the following spring. The mechanisms that start and end diapause are unknown. Third and fourth instar larvae are tended by ants. These instars have well-developed honeydew secreting glands that entice ants into this tending behavior. Pupation occurs in the soil beneath the host plant. One generation of butterflies is produced each year. Colonies are located at sites ranging from 690 to 1,180-foot elevation. Some colonies occur in the fog belt of the coastal range. Coastal chaparral and coastal grasslands dominate the vegetation type where colonies are found.

Distribution

The mission blue butterfly was first collected in 1937 from the Mission District of San Francisco. Today a small colony is located on Twin Peaks. The species has also been collected from Fort Baker, Marin County. The majority of the remaining colonies are found on San Bruno Mountain, San Mateo County. Other colonies have been discovered in San Mateo County.

Conservation Status

Twin peak population re-discovered in 2001. Numbers appear stable based on monitoring of San Bruno Mountain Habitat Conservation Plan.

Conservation Needs

Working with landowners

Most of the butterflies are on private land so some sort of landowner education as well as safe harbor agreements may be appropriate.

Education

Education sheets available at zoological facilities (e.g. zoos, aquariums, botanical gardens with butterflies, butterfly houses, natural history museums) or events at which BFCI partners participate are a valuable way to disseminate information about imperiled butterflies.

When schools and other youth organizations study biodiversity and species extinctions they typically use examples of charismatic megafauna (e.g. bald eagles) or exotic creatures from the tropics. However, vulnerable species found within the state or ecoregion in which students live provide an excellent opportunity to develop curricular materials with a direct link to the students' home region. In addition to classroom studies, students may be able to visit sites to see the butterflies, as well as talk to the scientists and land managers involved in the species' conservation.

Educational activities that school students and community members could do include:

• studying butterfly (insect) life stages;
• researching the special habitat needs of the mission blue;
• corresponding or meeting with the biologists managing current mission blue sites;
• visiting mission blue sites during adult flight season;
• visiting captive breeding programs;
• assisting scientists with on-site habitat management;
• propagating and growing host plants for planting at butterfly sites or use in captive breeding programs; and
• writing letters to decision makers to ensure that the mission blue receives adequate resources and protection.

Research

Insufficient information available at time of publication

Captive Rearing

Insufficient information available at time of publication.

Recovery Plan

Draft San Bruno Elfin and Mission Blue Butterflies Recovery Plan. October 10, 1984.

There has never been a final recovery plan for the Mission blue butterfly. A draft recovery plan was produced in 1984. Much of the information in this plan is outdated but it would be a good starting point for the development of a current recovery plan for the species.

Current management on San Bruno Mountain and in other areas focuses on reduced pesticide use, careful recreation management, and vegetation management. Several areas from which populations had been previously extirpated are also being targeted for re-vegetation and reintroduction of the butterfly. Much of San Bruno Mountain is a county park. The park mangers are the lead people in amending the Habitat Conservation Plan.

Surveys at San Bruno Mountain are not intensive enough to make population estimates or determine trends. Implementation of essential grazing and prescribed fire has not occurred under the HCP therefore, habitat quality has likely declined which may be negatively affecting the butterfly species.

The recovery plan for the Mission blue butterfly also includes the San Bruno elfin butterfly. The primary objective of the recovery plan is to protect, maintain, and enhance existing populations. The Mission blue butterfly may be reclassified to Threatened when secure, self-sustaining colonies are established or reestablished on two identified sites and the San Bruno Mountain populations are secure. Delisting is contingent upon protection, maintenance, and/or expansion of current colonies and establishment of additional colonies.

Recovery Priorities

In order to meet the above recovery criteria, the following activities are outlined in the recovery plan:

• Protection of essential habitat from adverse development on and outside of San Bruno Mountain through cooperative agreements, easements, and other strategies;
• Prevention of further habitat degradation from herbicides, pesticides, other toxicants, and off-road vehicle use. Habitat should be enhanced when possible by the removal of exotic plants and transplanting native flora;
• Development and implementation of management plans for existing colonies of butterflies after gathering information on bionomics, determining reclassification and habitat criteria necessary for reclassifying and delisting, and evaluating management data for long term planning for butterfly management at all locations;
• Reestablishment of populations in restored or rehabilitated habitats within historic range;
• Enforcement of laws and regulations to protect these butterflies and their habitats; and
• Development and implementation of an information and educational program.

In order to accomplish the interim objectives and formulate primary objectives, the following recovery activities are listed in the plan:

• Preserve and protect populations at all known, new, and reestablished sites.
• Establish three new, self-sustaining viable populations on suitable secure habitats of at least two hectares.
• Conduct ecological studies to develop management recommendations, determine larval and adult host plants, physiological requirements, demographics, and other biological/ecological studies, and to determine criteria for declassifying and delisting.
• Develop and implement public information and education programs.
• Enforce laws and regulations prohibiting illegal take and enforce land use plans and ordinances.

For more information

• USFWS Recovery Coordinator/Contact: Jim Browning, Sacramento Fish and Wildlife Office, 2800 Cottage Way, Room W-2605, Sacramento, California 95825. Phone (916) 414-6600
• Entomological Consulting Services, Ltd: Richard Arnold, 104 Mountain View Court, Pleasant Hill, California 94523-2188. Phone (925) 825-3784

References and Resources

• Arnold, R. A. 1980. Ecological studies on six endangered butterflies (Lepidoptera: Lycaenidae); island biogeography, patch dynamics, and the design of habitat preserves. Berkeley, CA. Univ. of Calif., Berkeley. Ph.D. dissertation.
• Arnold, R. A. 1983. Ecological studies of six endangered butterflies (Lepidoptera, Lycaenidae): island biography, patch dynamics, and design of habitat preserves. Univ. of Calif. Publications in Entomology. 99:1-161.
• Downey, J. C. 1957. Infraspecific variation and evolution in populations of Plebejus icarioides (Bdv.) Davis, CA. Univ. of Calif., Davis. Ph.D. dissertation.
• Thelander, C. ed. 1994. Life on the edge: a guide to California's endangered natural resources. BioSystem Books. Santa Cruz, CA. p 430-431.
• U.C. Berkeley, Essig Museum of Entomology. California's Endangered Insects Mission Blue page.
• U.S. Fish and Wildlife Service. 1984. San Bruno Elfin and Mission Blue Butterflies Recovery Plan. Portland, Oregon.
• Sacramento Fish and Wildlife Office Endangered Species Division Mission Blue Resources
• USFWS Mission Blue page

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Classification

Federal Endangered Species (Federal Register: 41:22044; June 1, 1976)

State Status

No state designation beyond the federal classification.

Range

CA

Critical Habitat

None designated

Acknowledgement

This profile was prepared by the Xerces Society for the Butterfly Conservation Initiative.