Euphilotes enoptes

Geographic Range

Blue dotted butterflies are found in the United States west of the Mississippi River and in Canada (Miller 1992). Populations tend to occur sporadically in conjunction with their host plant, Eriogonum compositum, a wild buckwheat (Peterson 1997). (Miller, 1992; Peterson, 1997)


Euphilotes enoptes is intimately associated with its host plants, where both it and the plants live in different elevations of the same geographic region (Peterson 1995). Within this region they tend to live in sun-exposed rocky or sandy flats or slopes in foothills, mountains, desert, and along coast (Opler, 2001). (Opler, P.A., 2004; Peterson, 1995)

Physical Description

Eggs – The eggs are a pale bluish-green color that eventually turns white.

Larvae – The larvae vary among the subspecies in color from ivory white to yellow to brown.

Pupa – Among the subspecies the pupa also vary in color, ranging from brown to yellowish-brown to translucent yellow. (Scott 1986)

Adults – The appearance of adults varies with the geographic region. The upperside of the male is lilac blue surrounded by darker borders while the female tends to be brown with an orange spot or patch on the hindwing. Both sexes have similar undersides, typically off-white with brown spots. The black dots on the forewing are predominantly larger and more square-like than those of the hindwing with an orange band on the hingwing separated into dashes. (Opler, 2001) (Opler, P.A., 2004; Scott, 1986)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range wingspan
    18 to 23 mm
    0.71 to 0.91 in
  • Average wingspan
    20 mm
    0.79 in


The development of blue dotted butterflies contains four main stages. The first stage is the egg, which is laid on the host plant. The second stage is the larvae that hatch from the eggs. The larvae then eat the flowers and developing seeds of the host plant in order to prepare for the formation of the pupa. Euphilotes enoptes leave the host plant and pupate at the base of the plant, usually in the soil or litter below it. When they emerge as adults, they continue the life cycle on and around the host plant (Peterson 1995). (Peterson, 1995)


The host plant is central to the reproduction process as males search around the host plant for females. During courtship males land after females, and both contact each other and flutter their wings before they copulate (Scott 1986). The female then oviposits, or lays, the eggs on the flowers and buds of newly opened inflorescences, where they will hatch into larvae that will then eat the flowers and their developing seeds. It is because of this that the window for reproduction is so small; if there were no flowers for the larvae to eat they would die and the attempt at reproduction would be unsuccessful (Peterson 1995). (Peterson, 1995; Scott, 1986)


Adults have a short life span that is typically two to nine days long (Peterson 1995). (Peterson, 1995)


Males tend to "patrol" the host plant to seek females with whom they mate (Scott 1986). (Scott, 1986)

Food Habits

The larvae feed on the developing seeds, young fruit, and flowers of the host plant (Peterson 1995). Adults sip the nectar of flowers (esp. host flowers) and mud (Scott 1986). It is obvious that the host plants are essential to the feeding habits of blue dotted butterflies. (Peterson, 1995; Scott, 1986)

  • Plant Foods
  • seeds, grains, and nuts
  • fruit
  • flowers

Ecosystem Roles

The caterpillars have a honey gland which secretes a sugary solution that ants eat. ("euphilot enoptes frames", 2002)

Mutualist Species
  • Formiciade

Conservation Status

Due to the destruction of its habitat in California, the subspecies Euphilotes enoptes smithi was placed on the Endangered Species List in 1984 (Sbordoni and Forestiero 1998). (Sbordoni and Forestiero, 1998)


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

Sarah Raison (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


an animal that mainly eats leaves.


an animal that mainly eats fruit


an animal that mainly eats seeds


An animal that eats mainly plants or parts of plants.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.


This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


2002. "euphilot enoptes frames" (On-line). Accessed 12/13/04 at

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

Opler, P.A., 2004. "Butterflies of North America -- Euphilotes Enoptes" (On-line). Accessed October 4, 2001 at

Peterson, M. 1997. Host Plant Phenology and Butterfly Dispersal: Causes and Consequences of Uphill Movement. Ecology, V. 78: 167-180.

Peterson, M. 1995. Phenological Isolation, Gene Flow, and Developmental Differences Among Low- And High-Elevation Populations of *Euphilotes enoptes* (Lepidoptera: Lycaeidae). Evolution, V. 49: 446-455.

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

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