Fender’s Blue (Aricia icarioides fenderi)
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
Caterpillar
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.
Pupa
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.
Average wingspan: About 1 inch
Flight pattern: Rapid wing movements; erratic flight
Eggs
Rounded eggs deposited singly on the underside of a Kincaid’s lupine leaflet
Quick Facts |
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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.


Scientific Classification

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

