Zayante Band-winged Grasshopper

Trimerotropis infantilis

Description

The Zayante band-winged grasshopper, Trimerotropis infantilis, was first described in 1984 from a sand parkland area near Mount Hermon in the Santa Cruz Mountains, Santa Cruz County, California. The body and forewings are pale gray to light brown with dark crossbanding on the forewings. The basal area of the hind wings is pale yellow with a faint thin band. The hind tibiae (lower legs) are blue gray and the eye is banded. It is one of the smallest species in the genus. Males range in length from 0.5-0.6 in (1.3-1.5 cm); females are larger, ranging in length from 0.7-0.8 in (1.8-2.0 cm).

The Zayante band-winged grasshopper is one of 56 species in the genus Trimerotropis. This species is similar in appearance to T. occulans and T. koebelei; neither of these species is known to the Zayante sand hills region. T. thalassica and T. pallidipennis pallidipennis have been caught nearby but are not considered sympatric.

Behavior

The flight season of the Zayante band-winged grasshopper extends from late May through August with peak activity during July and August. Specimens have been collected as late as November 1. When flushed, individuals generally fly 3-7 ft (91.4-213.3 cm), stridulating (producing a buzzing sound) in flight. Band-winged grasshoppers often alight on bare ground, and they are conspicuous in flight because of the color of the hind wings and the crackling sound made by the wings. No additional information on the life cycle of this species is available.

Habitat

The habitat of the Zayante band-winged grasshopper was originally described as sandy substrate sparsely covered with lotus and grasses at the base of pines. Subsequent reports describe the habitat as open sandy areas with sparse low annual and perennial herbs on high ridges with sparse ponderosa pine. Such descriptions are consistent with those of sand parkland. Surveys also report that the Zayante band-winged grasshopper co-occurs with Erysimum teretifolium (Ben Lomond wallflower), a federally endangered plant. The significance of such an association is unknown.

Distribution

The Zayante band-winged grasshopper is narrowly restricted to sand parkland habitat found on ridges and hills within the Zayante sand hills ecosystem. The species was described from specimens collected in 1977 on sparsely vegetated sandy soil above the Olympia sand quarry. Earlier specimens were labeled only "Santa Cruz Mts., no date;" "Alma, 1928;" "Felton, 1959;" and "Santa Cruz, 1941." Because no specific location or habitat descriptions accompanied the original historic specimens, they were not considered in the assessment of current range and status of the species. The "Alma 1928" record may suggest distributional outliers, but no subsequent collections have been recorded to substantiate the current existence of such a population. Furthermore, the town of Alma has been inundated by a reservoir, and the cited specimens cannot be located in the listed depository for verification.

Between 1989 and 1994, Zayante band-winged grasshoppers were found at 10 of 39 sites sampled during two independent regional surveys. All 10 collection locations were on Zayante series soils. The habitat at these sites was consistently described as sparsely vegetated sandy substrate or sand parkland. The association and restriction of the Zayante band-winged grasshopper to sand parkland was further corroborated by an overlay of collection locations on maps delineating sand parkland habitat. All 10 collection locations fell within seven discrete areas of sand parkland habitat.

Threats

The Zayante band-winged grasshopper is primarily threatened by habitat destruction through sand mining and urban development. Other lesser sources of habitat loss and alteration are recreational activities and agriculture.

The vast majority of habitat loss can be attributed to sand mining and urban development; over 60% of historic sand parkland is estimated to have been lost through and altered by the above human activities. Only 49 acres (19.6 hectares) of sand parkland habitat are publicly owned: 3 acres (1.2 hectares) of high quality and 6 acres (2.4 hectares) of low quality habitat are protected within the Quail Hollow Ranch, owned by the County of Santa Cruz; 20 acres (8.0 hectares) of low quality sand parkland are protected in the Bonny Doon Ecological Preserve, managed by the California Department of Fish and Game; and approximately 20 acres (8.0 hectares) of low quality habitat occur in Henry Cowell Redwoods State Park. The Zayante band-winged grasshopper does not occur in the Bonny Doon Ecological Preserve or Henry Cowell Redwoods State Park. The remaining 143 acres (57.2 hectares) of sand parkland are privately owned and at risk of loss to sand mining and urban development. Nine of the 10 Zayante band-winged grasshopper collection sites are adjacent to areas used for sand mining, and these insects are susceptible to the same elimination through crushing and exposure as the Mount Hermon June beetle. One site where Zayante band-winged grasshoppers were previously collected is now a parking lot. Two known locations of Zayante band-winged grasshoppers are adjacent to residential, commercial, and public developments.

Collection of the Zayante band-winged grass-hopper has occurred during surveys for this and other invertebrate species, but overutilization by collection is not a current threat.

One Zayante band-winged grasshopper specimen was observed to be parasitized by a tachinid fly. However, the significance of parasitization on populations of this species is unknown.

Pesticides could pose a threat to the Zayante band-winged grasshopper. Pesticide application is expected at existing and planned golf courses and may also occur on a limited basis at vineyards in the area. Local landowners may use pesticides to control targeted invertebrate species around homes and businesses. These pesticides may drift and kill nontargeted species such as the Zayante band-winged grasshopper.

Conservation and Recovery

The seven discrete areas of sand parkland containing the 10 currently known collection sites have been secured through fee-title acquisition, conservation easements, or habitat conservation plans for Graniterock Quarry, Kaiser Sand and Gravel Felton Plant, and the County of Santa Cruz. A management plan for Quail Hollow County Park has been developed and is being implemented, and the population numbers are stable or increasing.

Contact

Regional Office of Endangered Species
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

Reference

U. S. Fish and Wildlife Service. 1998. "Recovery Plan for Insect and Plant Taxa from the Santa Cruz Mountains in California." U.S. Fish and Wildlife Service, Portland.