Faunal study of velvet ants (Hymenoptera: Mutillidae) and their activity pat-terns and habitat preference at Ash Meadows National Wildlife Refuge, Nye County, Nevada, USA

The diversity of velvet ants at Ash Meadows National Wildlife Refuge (AMNWR) is investigated along with seasonal flight time and habitat preference for each species. Of the 45 (SD ± 2) species expected to occur at AMNWR via first order jackknife estimator, 42 species were found to occur based on 8843 specimens. Variation in flight times between specieswere minor and revealed a unique pattern of niche partitioning in only one species, Dasymutilla arenivaga Mickel. Habitat preferences were observed for seven species at AMNWR. Dasymutilla arenivaga, Odontophotopsis melicausa (Blake), and Sphaeropthalma orestes (Fox) were found to be more abundant in sand dune habitats than in non-sand dune habitats. While four other species, Odontophotopsis mamata Schuster, O. microdonta Ferguson, O. serca Viereck, and Sphaeropthalma mendica (Blake), were found to be more abundant in non-sand dune habitats. The diversity of velvet ants found at AMNWR was compared to the diversity of velvet ants found at the Nevada Test Site (NTS) located approximately 25 mile northeast of Ash Meadows. This comparison identified six velvet ant species that occurred at the NTS, but were not found at AMNWR. The status of Photopsis nana Ashmead 1896 is reinstanted. New synonymy is proposed for Photopsis nana Ashmead 1896 (=Mutilla acontius Fox, 1899, syn. nov.). Diagnoses and a key are provided for the velvet ants of AMNWR. The hitherto unknown female of Sphaeropthalma megagnathos Schuster is described, and an updated key to the females is provided for S. imperialis species-group. Lectotypes are designated for twelve species.

Holocene dune formation at Ash Meadows National Wildlife Area, Nevada, USA

Small isolated dune fields in the northern Mojave Desert are important centers of biodiversity and archaeological occupation sites. Currently dunes at Ash Meadows, Nevada, are stabilized by vegetation and are experiencing erosion of their upwind margins, indicating a negative sediment budget. New OSL ages from dunes at Ash Meadows indicate continuous eolian accumulation from 1.5 to 0.8 ka, with further accumulation around 0.2 ka. Prior studies (e.g., Mehringer and Warren, 1976) indicate periods of dune accumulation prior to 3.3 ka; 1.9–1 ka; and after 0.9 ka. These periods of eolian accumulation are largely synchronous with those identified elsewhere in the Mojave Desert. The composition of the Ash Meadows dunes indicates their derivation from regional fluvial sources, most likely during periods when axial washes were active as a result of enhanced winter precipitation.