Celastrina ladon
Spring Azure

Family Description:
Note: This is really a complex comprised of several species or subspecies, including C. echo, C. lucia, and possibly others. Some authors refer to this species as Celastrina argiolus.

Caterpillar: The caterpillars vary a great deal in color, and can be green, yellow, pink, or brown. The back may be striped lengthwise with green or brown and spotted with white. The average, full-grown length is 1/2 inch.
Adult: This is a small butterfly, with a wingspan of 3/4 to 1 3/8 inches. Its appearance varies seasonally and between the sexes. Spring: Typically in spring, the upperside is a silvery violet blue, with black shading on the outer edge of the forewings of females. Underneath is grayish, with a black-and-white checkerboard border and possibly with black spots. It may have a blotchy appearance. Late spring/early summer: Upperside is similar to spring’s but marked with white; females’ wings are edged in black. Underneath is gray to white and may be marked faintly.

A widespread species, it can be found in Alaska, throughout Canada and the U.S., and south through Mexico and the mountains of Central America. It occurs throughout much of Idaho.


It occupies a variety of habitat types, including fields, roadsides, meadows, marshes, swamps, in or near woodlands, and sagebrush steppe.


Caterpillar: Caterpillars feed on the flowers and fruits of a variety of plant species, including dogwoods (Cornus spp.), buck brush (Ceanothus spp.), meadowsweet (Spirea spp.), and viburnum (Viburnum spp.).
Adult: Butterflies use flower nectar food. They can often be seen puddling at mud or dung.

The caterpillar is equipped with a honey gland, also known as a dorsal nectary organ, which emits a sugary solution agreeable to ants. The ants feed on the solution and in turn protect the caterpillar from predators. Also for protection, the caterpillar bears a pair of everscible tubercles or tentacles on the eighth segment. These tubercles are usually housed within the body, but when the caterpillar feels threatened by the approach of a potential predator, they can be pushed out to release a chemical which mimics an ant alarm pheromone. This scent causes the ants to become frenzied and aggressive, and the potential predator takes leave or is eaten by the ants. Each caterpillar undergoes four stages of growth, or instars. There can be several generations of caterpillars each growing season, with the last generation pupating before overwintering in a physiological state called diapause. Adults generally fly from March to early July. The spring butterflies are one of the first species to emerge after winter.


Males actively patrol in search of receptive females, and may occasionally perch. Females lay eggs singly on the flower buds of host plants.

Idaho Status: Unprotected nongame species.
Global Rank: Unranked; some species/subspecies have low population levels that are of concern.

Ballmer, G. R. and G. F. Pratt. 1988. A survey of the last instar larvae of the Lycaenidae of California. Journal of Research on the Lepidoptera 27:1-81.

Ferris, C. D. and F. M. Brown. (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. http://www.npwrc.usgs.gov/resource/distr/lepid/bflyusa/bflyusa.htm (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies.    Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.