Cupido comyntaseastern tailed-blue

Geographic Range

Cupido comyntas can be found in the upper Sonoran Zone to lower Canadian foothills, or the lower Canadian Zone in the east. Most populations are found in the eastern United States and Canadian areas. There are some isolated colonies in Oregon and California. (Milne, 1980; Scott, 1986; Tveten, 1996)


The habitats in which they live are usually moist meadows, desert foothills, stream sides, roadsides and forest paths or clearings. Also, they are attracted to weedy fields and gardens. This causes Cupido comyntas to profit from human encroachment. (Milne, 1980; Scott, 1986; Tveten, 1996)

Physical Description

Tailed blues have a wingspan of 7/8 - 1 1/8". The wings of the males are pale blue with a brownish tint on the sides. There is a small orange spot at the base of the tail of these butterflies. Females have larger wings that are gray with a shot of blue streaking down them. The underside of the female's wings are gray and white with a curved row of gray spots. The hindwings have eyespots. During the spring the females are bluer than during the summer, when C. comyntas is brown. There are two orange spots on the underside of the butterfly, and the upper side has an orange spot on the males. (Carter, 1992; Milne, 1980; Scott, 1986)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range wingspan
    .022 to .035 m
    0.07 to 0.11 ft
  • Average wingspan
    .028 m
    0.09 ft


The eggs from C. comyntas are laid on the leaves and flowers. The eggs, which are pale green in color, will develop into mature larvae that hibernate within the host's pod. The caterpillars are hairy with a dark green body. They also have dark brown stripes and a small black head. The caterpillars will use the flower bud that they were laid on as food, and then will later construct and hibernate their cocoon for the winter months. In the spring, an E. comyntas butterfly will emerge from the cocoon, and the life cycle will start over again. (Scott, 1986)


The males will look for mates during warm, daylight hours. Usually mating takes place from late morning to midafternoon. Female C. comyntas butterflies lay their eggs on immature flowering buds, in order to preserve the flowers for the caterpillars when they hatch early in the season. There are usually two or more generations a year. (Carter, 1992; Milne, 1980; Neck, 1996; Stokes and Stokes, 1991; Tveten, 1996)

Beyond developing, laying, and fertilizing eggs, adults show no parental involvement with their offspring.

  • Parental Investment
  • pre-fertilization
    • provisioning


Tailed blues live in habitats where there are humans. They fly from the spring to the fall (about March to November), and also keep flight during the day. They are weak fliers, fly just above the tops of grass, and stay in sunny environments. (Carter, 1992; Milne, 1980; Tveten, 1996)

Food Habits

Cupido comyntas has a short proboscis (the small, flexible snout which the butterfly uses to sip nectar), which restricts it to feeding from open or short-tubed flowers. Blossoms are also frequently visited by this species. Often E. comyntas will fly to mud puddles for water, which provide it with amino acids and dissolved minerals. Its favorite food plants are lupine and vetch. The caterpillar of E. comyntas eats clover and other leguminous plants. (Milne, 1980; Stokes and Stokes, 1991; Tveten, 1996)

  • Plant Foods
  • leaves
  • nectar


Cupido comyntas has a mutualistic association with ants. The caterpillars of this species secrete a "honeydew" from their abdomen. This liquid is rich in sugars and proteins. The liquid feeds the ants, and in return the ants protect the caterpillars against any possible predators.

Additionally, when E. comyntas senses a potential predator, it will rub its hindwings together to divert the predator from its vulnerable foreparts. (Stokes and Stokes, 1991; Tveten, 1996)

Ecosystem Roles

This species acts as a pollinator, and also as an herbivore. It also may be prey to many other species.

  • Ecosystem Impact
  • pollinates

Conservation Status

Conservation for the E. comyntas is not usually required. The Nature Conservancy Global Ranking system gives this species a rank of G5 which means that the E. comyntas is secure, but might be rare in some parts of its geographical range. (Opler 1992)

Other Comments

Cupido comyntas are in the same family as coppers, metalmarks and hairstreaks. This family contains some of the smallest species of butterflies. There is a subspecies of E. comyntas in Texas called E. c. texanus (Texas Tailed Blue). Also, E. comyntas is the only Nearctic member of the Plebejini which has tailed hind wings. (Ehrlich, 1961; Neck, 1996; Stokes and Stokes, 1991)

Cupido comyntas are in the same family as coppers, metalmarks and hairstreaks. This family contains some of the smallest species of butterflies. (Ehrlich, 1961; Neck, 1996; Stokes and Stokes, 1991)


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

Chelsey Clammer (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.

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.

  1. active during the day, 2. lasting for one day.

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.


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


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.


the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

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.

native range

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


an animal that mainly eats nectar from flowers


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


Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season


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


Living on the ground.


Carter, D. 1992. Butterflies and Moths. New York: Houghton Mifflin Company.

Ehrlich, P. 1961. How to Know the Butterflies. Dubuque, Iowa: W. C. Brown Co..

Milne, L. 1980. The Aubudon Society field guide to North American insects and spiders. New York: Random House.

Neck, R. 1996. A Field Guide to Butterflies of Texas. Houston, TX: Gulf Pub. Co..

Opler, P. 1992. A Field Guide to Eastern Butterflies. Boston: Houghton-Mifflin Co..

Scott, J. 1986. The Butterflies of North America. Standford, CA: Standford University Press.

Stokes, D., L. Stokes. 1991. The Butterfly Book. Boston: Little Brown.

Tveten, J. 1996. Butterflies of Houston and Southeast Texas. Austin, TX: University of Texas Press.