Friday, after being fortunate enough to receive our second dose of the COVID 19 vaccine, Pam and I headed up to The Cliff so I could complete my identification of the Cardamine nuttallii. I was irritated with myself because my failure to be thorough had engendered a need for this 45 minute drive, and Pam, who was feeling a bit under-the-weather even before the inoculation, was not keen on an extended expedition.
But then we got there and it was so lovely (blue skies, puffy clouds, dappled shade, wildflowers in bloom, textured forms of trees and ferns, bright green mosses on the cliff, warm but not hot, dozens of Enchoria lacteata moths fluttering about, recognizable even in flight by the dulled flashing of cream and brown), that our spirits rose and Pam drifted along the road while I made my measurements and took my photos.
Then a stroboscopic flashing of black and white! Suddenly my whole mood shifted from diligence and pastoral appreciation to excitement. I tracked it until it disappeared into the woods, and then another and another, but none of them would settle down for a photograph. Not knowing how many might be about, I traded my camera for a net, and soon captured a specimen of the glorious little diurnal (day flying) Geometrid moth, Mesoleuca gratulata (which I released after refrigeration had calmed it enough for some portraiture). And shortly after I re-exchanged the net for a camera I did find a cooperative Western White-ribboned Carpet Moth perched on a C. nuttallii, and got some in situ photographs. Usually I start finding these by mid March, but these were the first ones I’d seen this year.
So, between being fully vaccinated, having a glorious spring day at a beautiful location in which to be wandering about with my wife, and finding the FOY (first of the year) of one of my favorite moths (symbol of springs arrival that they are), I had an abundance of reasons to be gratulata (express joy or gratification).
Description– Small (fw length 11-13mm), mostly black and white moth, with a large irregular band of white in the median area, a large black discal spot, and a bright white hindwing; usually has brown along the postmedial line where it juts rearward, bluish white to silver speckling in the black areas, and black dashes for a subterminal line.
Similar species– M. ruficillata has a much smaller discal spot, the white band midwing is more uniform in width, and it flies in summer rather than early spring.
Habitat– Moist to mesic mixed forests and woodlands.
Range– Western North America; primarily west of the Cascades in our region, with an eastward expansion into the Columbia River Gorge; probably more widespread, but unnoticed due to early emergence and small size.
Eats– Larvae are known to feed on the leaves of Rubus sp., in particular on blackberries and thimble berries, and on Corylus spp. (hazelnuts).
Reproduction– Single eggs are laid on various Rubus sp.; within 5 weeks the eggs have hatched, the larvae have completed their growth and have pupated; they overwinter and emerge as adults the following spring.
Adults active– February to early June; peaks in April.
Etymology of names– Mesoleuca translates from the Greek as ‘white middle’, and refers to the midwing white band of this genus. The specific epithet gratulata is from the Latin for ‘to express joy or gratification’ which captures very well the feelings I have when I see the first of these each year, because they don’t just herald the spring, they shout that it is here!