Since I’m hanging out indoors today while snow falls steadily, covering every exposed horizontal surface, I thought I’d look back to sunnier times, and in doing so I found these photos from the first time I managed to take sharp enough photos to positively identify a Becker’s White.
Pontia beckerii is a butterfly of the high desert, common in wide open spaces wherever weedy mustards are available to feed their larvae. They are a welcome sight in many treeless areas, white wings flashing in the unfiltered sunlight as they flutter by. And when they do stop to rest or nectar, the glorious golden green of their underwings is a wonderful counterpoint to the sere browns, drab greys, and muted olives of the shrub steppe country.
Description– Fairly large (ws 2”) butterfly for Pieridae; white dorsal fw surface with dark markings at the wingtips and a dark rectangular box with white interior mid-wing; dorsal hw white with dark, irregular marks at margins; ventral hw with strong green borders to the veins, which are interrupted midway; ventral fw with green bordered veins toward the wingtips.
Similar species– P. sisymbrii (Spring White) is smaller, has a solid dark bar on the fw and thin black vein, ventral hw veins are bordered in brown rather than green and are unbroken, and females are yellowish; P. occidentalis dorsal fw has a less obviously open rectangular bar and thin black veins, and the ventral hw veins are less sharply bordered in green, and are unbroken.
Habitat-Arid sagebrush and shrub steppe
Range-Primarily east of the Cascades and west of the Rockies
Eats-Many different mustards serve as larval hosts; adults are non-specific nectarers.
Adults active– Mid March to mid September, with peaks in May and August.
Etymology of names–Pontia appears to reference Pontus, the original divinity that was the sea, in Greek mythology. The specific epithet beckerii honors the German naturalist Ludwig Becker (1808-61).