Home / Gossamer-Winged (Lycaenidae) / Fender’s Blue (Aricia icarioides fenderi)

Fender’s Blue (Aricia icarioides fenderi)


Fender’s Blue Butterfly

The Fender’s Blue is an endangered subspecies of the Boisduval’s Blue butterfly found in parts of the USA. This is a very tiny butterfly that was not seen after the 1930s and was presumed to have gone extinct. Later, small populations were rediscovered in 1989. They are mostly seen during the summer, in around April and May.

Scientific Classification

  • Family: Lycaenidae
  • Genus: Aricia
  • Scientific Name: Aricia icarioides fenderi

Description and Identification


The mature larva is very tiny with a green coloration. They have a segmented body and may develop a dark mark across the middle of the body in the next instars.


The chrysalis is light green to greenish brown and continues this stage at the base of the host plant, where they overwinter and come out as an adult butterfly after the arrival of spring.

Adult Butterfly

Sexual Dimorphism: Distinctly present

Color and Appearance: When the wings are open, the dorsal side of the wings of males shows up an iridescent sky blue coloration, whereas the females show a rusty brown hue. The upper side of both the sexes display a white fringe bordered by black. When the wings are closed, the ventral side shows a pearly gray to dull white color studded with spots in black and brown that are outlined in white.

Male Fender’s Blue Butterfly
Female Fender’s Blue Butterfly

Average wingspan: About 1 inch

Flight pattern: Rapid wing movements; erratic flight


Rounded eggs deposited singly on the underside of a Kincaid’s lupine leaflet

Quick Facts

Distribution Only in the Willamette Valley of northwestern Oregon, USA
Habitat Native upland prairies
Lifespan of adults 10 days (average)
Host plants Mostly lupines
Adult diet Flower nectar

Did You Know?

The butterfly had been officially declared as ‘endangered’ on January 25, 2000, and presently by the ESA.

Fender’s Blue Butterfly Habitat
Aricia Icarioides Fenderi
Fender’s Blue Butterfly Images

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Scientific Classification

  • Family: Lycaenidae
  • Genus: Aricia
  • Scientific Name: Aricia icarioides fenderi
Published by Poppy Glendening on June 1, 2019.
Last Updated: October 15, 2023. ✅ Verified by: Butterfly Team