We've seen bumble bees, honey bees, sweat bees, wool carder bees and syrphid flies topple into our  swimming pool, but never an alfalfa butterfly until now.

This male alfalfa butterfly--the gender identified by noted butterfly expert Art Shapiro, professor of evolution and ecology at UC Davis--bumbled into our pool early one morning. Not sure why it fell into the pool. It spiraled over the catmint, fluttered over the pool, and then dropped into the water. Not very gracefully, either.

We netted it and placed it on a flowering artichoke so it could rest a bit and dry its wings.

The alfalfa butterfly, Colias eurytheme (common name "orange sulphur" or "alfalfa butterfly") is a significant pest of alfalfa, Shapiro says on his website, Art's Butterfly World. It "overwinters as a larva almost entirely in annual vetch at low altitudes, and colonizes alfalfa only as the vetch senesces in May-June. Aside from alfalfa and annual vetches, it also breeds on a variety of clovers and sweet clovers and occasionally on lupines."

"An oddity of sulphurs is that their orange and yellow pteridine pigments are water-soluble," Shapiro told us today. "Had it remained in the water long enough, its scales would have been leached to translucency."

And, he pointed out, "Colias that sit out in the alfalfa during overhead irrigation regularly get water-spotted."

This one not only survived but so did its colors.