Hesperopsis gracielae

Macneill's Sootywing

Family: Hesperiidae · Class: Insecta · Order: Lepidoptera

Conservation status: G2? S1S2

Macneill's Sootywing (Hesperopsis gracielae) is a small skipper butterfly endemic to the southwestern United States desert regions. Adults measure approximately 25-30 mm (1.0-1.2 inches) in wingspan. The species displays the characteristic sooty-brown coloration typical of sootywing skippers, with dark brown to blackish forewings marked by small white spots arranged in irregular patterns. The hindwings are similarly dark with less distinct markings. Males possess specialized scent patches (stigma) on their forewings used in courtship behaviors. The antennae are relatively short with distinctive hooked clubs, and the body is robust and hairy, typical of hesperiid skippers. Macneill's Sootywing occurs along the Colorado River corridor from southern Utah through southern Nevada and southern Arizona, with an isolated population in California's Coachella Valley. This disjunct distribution reflects the species' association with specific desert wash and riparian edge habitats. The California population represents the westernmost extent of the species' range and is geographically isolated from the main Colorado River populations. The species inhabits desert washes, canyon bottoms, and alkaline flats where host plants thrive. These areas typically occur at elevations ranging from below sea level in the Coachella Valley to approximately 1,200 meters (4,000 feet) in higher desert locations. The butterfly requires areas with sparse to moderate shrub cover dominated by chenopod vegetation, often in sandy or gravelly substrates with intermittent water availability. Macneill's Sootywing larvae feed exclusively on plants in the goosefoot family (Chenopodiaceae), including shadscale (Atriplex canescens), quail brush (Atriplex lentiformis), and silverscale saltbush (Atriplex argentea var. expansa). Adults are active during daylight hours and exhibit rapid, erratic flight patterns typical of skipper butterflies. Males establish territories near host plant patches and engage in perching behavior to intercept potential mates. The species likely produces multiple broods per year, with peak activity occurring during spring and fall months when temperatures are moderate and host plants are actively growing. Females deposit eggs singly on host plant foliage, and larvae construct silk shelters by folding leaves together. Macneill's Sootywing holds a global conservation rank of G2?, indicating it is imperiled globally with 6-20 extant populations or few remaining individuals. In California, the species ranks S1S2, reflecting its critically imperiled to imperiled status within the state. Primary threats include habitat loss from urban development, particularly in the rapidly expanding Coachella Valley, agricultural conversion, water diversions affecting riparian corridors, and invasive plant species that displace native chenopod host plants. Climate change poses additional concerns through altered precipitation patterns and increased drought frequency in already arid habitats. The species' limited distribution and specialized habitat requirements make it particularly vulnerable to environmental changes and human disturbance.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.