The camel cricket, Utabaenetes tanneri Tinkham, has been little studied. This study gathered information on thebasic life history and behavior of this species, which is found only in the San Rafael Desert and adjacent Colorado Plateau in areas of loose sand or active dunes. The daily activity pattern is matutinal, and individuals construct burrows fro shelter in the afternoon. The diet of U. tanneri is omnivorous, composed of plant material, detritus, and conspecific crickets. Utabaenetes tanneri has been found in the diet of several predatory species, although the total number of observed predation instances is low. Utabaenetes tanneri might be a Batesian mimic of sympatric tenebrionid beetles, which might explain the small number of observed predation attempts on this species. Utabaenetes tanneri can be very abundant where it occurs. Abundance and density of crickets was determined for three study plots in Grafield County, Utah. Plot 1 had a mean abundance of 482 crickets, determined by mark and resight analyses, and a mean density of 0.23 individuals per square meter. Only one cricket was found in Plot 2, and no mark and resight analysis was performed. Plot 3 had a mean abundance of 50 crickets, and a mean density of 0.022 individuals per square meter. The bulk density of the soil was compared between the three sites, but no significant difference was found (Kruskal-Wallace X2 = 0.932, df = 2, P = 0.627), and therefore is probably not the reason for the differences in abundances between the three plots. Studies on similar species of sand treaders have indicated that they are important detritivores within arid ecosystems. They are also preyed on by numerous species, and are usually one of the most abundant arthropods where they occur. Utabaenetes tanneri probably functions in a similar ecological role to these
other species of sand treaders. In addition to these observations of U. tanneri, a morphological description of the species is provided. The first key to the subfamilies of Rhaphidophoridae in the United States and Canada is presented, along with a key to the genera of the subfamily Ceuthophilinae.
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