Our species profile for this issue is the Silver-bordered Fritillary, Boloria selene.

Fritillaries belong to the very large worldwide family Nymphalidae, the brushfoots. All fritillaries have a similar appearance dorsally, tawny-orange to carrot-orange with a complex pattern of black lines and dashes. “Frits” are divided into two groups, the greater fritillaries and the lesser fritillaries. The greater frits are generally larger and have oval spots, often silvered, on the ventral hindwing (vhw). The lesser frits are smaller and have white, or, in one Washington species, silvered, spots on the vhw which are not oval in shape. All greater frits in Washington belong to the genus Speyeria, and all lessers are in the genus Boloria. The smallest Speyeria (S. mormonia) is about the same size as the average female Boloria. In Washington we have eight species of greater frits and six species of lessers.

Of our six lesser fritillaries only two are widespread and easily found, while the other four are localized to rare. Boloria selene is one of our localized species, found in only a few places in the state, generally boggy habitats where violets grow. One tiny, localized population is found just southeast of Yakima at the Moxee Bog, a tiny relict population probably left over from the last ice age. This area is protected by the Nature Conservancy, but butterfly numbers are shrinking and the colony ‘is unstable. More robust Silver-bordered Fritillary populations are found in Okanogan County, particularly in the Mary Ann Creek area east of Oroville. Boloria selene is a candidate for listing in Washington, and in some other states, such as Illinois, scientists are attempting to reintroduce this species to areas where it was earlier extirpated by agricultural practices.

The Silver-bordered Fritillary is circumboreal. In North America it occurs widely across parts of Alaska and much of Canada, extending south into the northern part of the U.S. across the entire country. Along the Rocky Mountains its range dips the farthest south, into northern New Mexico. In Washington the Silver-bordered Fritillary can be found in Okanogan County and in the far northeast corner of the State, and tiny relict populations occur in at least five seep or bog areas across the Columbia Basin.

In Washington the Silver-bordered Fritilla1y is our only fritillary which is double-brooded, and in other regions it may even be triple-brooded. Second brood adults lay their eggs in July or perhaps even August, on or in close proximity to their violet food plants in seeps or boggy areas. After hatching the larvae feed up to second or third instar, then diapause through late summer and winter, becoming active again in the spring. They pupate and emerge as first brood adults in mid-May of the next year. The first brood adults repeat the cycle, except that their larvae do not diapause, but feed straight through, pupate, and emerge as second brood adults in July. The eggs have a truncated rounded-cone shape with numerous ribs, each rib with many small lateral cross-grooves. This egg shape is typical for all fritillaries. The larvae are splotchy gray with dark brown spots, a dorsolateral row of gold spots and numerous branching spines. Two “horns” extend forward over the head, appearing about third instar and growing rather long by the fifth instar. In the later caterpillar instars the head region becomes black, contrasting with the light gray-colored body and now-golden spines. The larva grows to about one inch before pupating to a handsome light brown chrysalis. The chrysalis has indentations and spiny projections, hanging suspended from a silk pad (cremaster), but lacking a silk girdle.

                

The Silver-bordered Fritillaty is the only lesser frit in Washington which has silvered spots on the vhw.  These spots are not oval in shape, making the species easy to separate from greater frits of similar size (Mormon Fritillaries). While the silvering of the spots is diagnostic, the central spot on the vhw is also distinct in shape, being roughly rectangular with the inner and outer corners truncated obliquely.

Males patrol conspicuously over grassy, boggy areas in the vicinity of violets, looking for females. Their flight is relatively slow and wafting. Females generally stay low in the vegetation and out of sight, and are best found by walking through the area and flushing them to flight, but care should be taken not to crush the violet foodplants underfoot.

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