SAND MOUNTAIN BLUE BUTTERFLY } Euphilotes pallescens arenamontana
DESCRIPTION: The Sand Mountain blue is a small butterfly with a wingspan just under an inch; males average 11.1 millimeters, while females are slightly smaller at 10.9 millimeters. Males have characteristic pale blue-violet upper-wing surfaces, with wing edges lightly lined in black and fringed in white. Females have brown or tan upper-wing surfaces with hints of blue coloration at the bases of both wings. For both sexes, the ventral wing surface is chalky white, with a pale orange aurora on the hindwing. Larvae are fat and grub-like.
HABITAT: Sand Mountain blue butterflies are closely linked to their larval host plant, Kearney buckwheat. This plant grows only on some southern dunes of Sand Mountain and functions as the sole food source for larvae as well as an important nectar source for adult butterflies. Kearney buckwheat also provides cover and a layer of ground litter in which pupae mature.
RANGE: The only known habitat for the Sand Mountain blue butterfly is on the Sand Mountain dunes within the Sand Mountain Recreation Area in Churchill County, Nevada.
MIGRATION: This species is nonmigratory. Typically, Sand Mountain blue butterflies remain within 200 feet of their host plant for their entire life cycle.
BREEDING: Sand Mountain blue butterflies produce one brood a year. Maturation of larvae occurs between mid-July and mid-September — in time for peak blooming of Kearney buckwheat.
LIFE CYCLE: Typically, within 24 hours of mating, a female butterfly will lay single eggs into buckwheat flower heads. Roughly a week later, the eggs hatch and become larvae. Larvae then feed on petals and fruit in the flower head. The Sand Mountain blue only lives about one week as an adult, and the overall population of adults is active for only a few weeks.
FEEDING: Larvae eat petals, fruit, and fallen leaves of Kearney buckwheat. Kearney buckwheat flowers are also a significant nectar source for adult butterflies.
THREATS: The butterfly is in jeopardy because of habitat destruction caused by off-road vehicle use.
POPULATION TREND: As much as 50 percent of Sand Mountain blue butterfly habitat has been destroyed.