Speyeria egleis tehachapina

Tehachapi Mountain Silverspot Butterfly

Family: Nymphalidae · Class: Insecta · Order: Lepidoptera

Conservation status: G5T2 S2

The Tehachapi Mountain Silverspot Butterfly (Speyeria egleis tehachapina) is a subspecies of the Great Basin Fritillary endemic to the Tehachapi Mountains of southern California. Adults have a wingspan ranging from 60 to 75 mm (2.4 to 3.0 inches). The dorsal wing surfaces display bright orange-brown coloration with distinct black markings forming a characteristic checkerboard pattern typical of fritillary butterflies. Males tend to be smaller and more intensely colored than females. The ventral hindwings exhibit the diagnostic silver spots that give this group its common name, with metallic silver markings against a pale background that distinguish it from other fritillary species. This subspecies occurs exclusively in the Tehachapi Mountains of Kern County, California, representing one of the most geographically restricted butterfly subspecies in the state. The historical range likely encompassed higher elevation areas throughout the Tehachapi range, but current populations are limited to scattered locations primarily on the western slopes. The subspecies is separated from other Speyeria egleis populations by significant geographic barriers and exhibits distinct morphological characteristics that support its taxonomic designation. Tehachapi Mountain Silverspot Butterflies inhabit montane meadows and forest openings at elevations between 1,200 and 2,400 meters (4,000 to 8,000 feet). The species requires areas with native violet species (Viola species), which serve as the sole larval host plants. Adults are typically found in meadows with abundant nectar sources including native wildflowers such as rabbitbrush, asters, and thistles. The subspecies shows strong habitat fidelity to areas with specific microclimatic conditions that support both violet populations and adult nectar resources. Adults are active from late June through August, with peak flight activity occurring in July. Females deposit eggs near violet plants in late summer, and larvae overwinter as first instars. Development requires two years to complete, with larvae feeding exclusively on violet foliage during their active periods. Males establish territories in meadow areas and engage in patrolling behavior to locate receptive females. Mating typically occurs in mid-morning hours when temperatures are optimal for flight activity. The Tehachapi Mountain Silverspot Butterfly carries a Global/State Rank of G5T2 S2, indicating the subspecies is imperiled both globally and within California. The limited geographic range makes this subspecies particularly vulnerable to habitat loss and environmental changes. Primary threats include habitat degradation from recreational activities, invasive plant species that displace native violets and nectar sources, and climate change effects that may alter the suitable elevation range. Drought conditions can significantly impact both larval host plants and adult nectar resources. Conservation efforts focus on habitat protection and monitoring of known populations, though the subspecies lacks formal federal or state endangered species protection. The restricted range and specialized habitat requirements make this subspecies a conservation priority for maintaining California's lepidopteran diversity.

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