Mount Hermon June Beetle

Polyphylla barbata Cazier, 1938
Date of listing: January, 1997
Federal Status: Endangered
State Status: None

The Mt. Hermon June Beetle is a member of the family Scarabaeidae, a group containing dung beetles, rhinocerous beetles, and many other well-known insects. This beetle is found in the Santa Cruz Mountains south of the city of San Francisco.

The Mt. Hermon June Beetle, like most scarab beetles have soil-dwelling, grub-like larvae. Like other species of Polyphylla, the Mt Hermon June Beetle is associated with sandy soils. The Santa Cruz Mts. are largely volcanic in origin but there are scattered patches of soils derived from sedimentary sources (limestones and sandstone) which tend to be sandier. These patches, known in the Santa Cruz Mts. as the Zayante Sand Hills formation, appear to be the primary, if not the only habitat of Polyphylla barbata.

The sandy habitat provides a different microclimate than is found elsewhere in the Santa Cruz Mountains. Sandy soils tend to drain better and are thus somewhat drier, warmer, and more sparsely vegetated. In addition to Polyphylla barbata, the Zayante Sand Hills support threatened plants (Santa Cruz cypress [Cupressus abramsiana], Silverleaf manzanita [Arctostaphylos silvicola]) and several other threatened insects, including the Zayante band-winged grasshopper and the Santa Cruz rain beetle.

The primary threats have been sand mining and urban development. At the time of listing it was estimated that 60% of the sand hills habitat had been disturbed. Of the remaining habitable areas, nearly two-thirds is unprotected (i.e. privately owned). The majority of known localities of the Mt. Hermon June Beetle are in close proximity to active sand mines. Though continued use of this habitat by mining companies will require some habitat restoration and revegetation, it is questionable whether true restoration is possible. Protection of remaining habitat should be the primary goal.

Further Reading

US Fish & Wildlife Service – Environmental Conservation Online

Santa Barbara Museum of Natural History – California Beetle Project

Zayante Sandhills Conservation Bank


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