New Species Records and Incidence of Bark Beetles and Ambrosia Beetles (Coleoptera: Scolytidae) from the Barrens of Middle Tennessee, USA

Nineteen species of bark beetles and ambrosia beetles (Coleoptera: Scolytidae) were collected from 8 of 11 sites located on Arnold Air Force Base within the barrens of the southeastern Highland Rim in middle Tennessee, USA. These barrens resemble the perennial grass-dominated prairies of the midwestern United States and are inhabited by many rare and disjunct plant species. Although much is known about the plant species in this unique area of biodiversity, little information is available on insect species. No previous reports have documented scolytid species in this unique habitat. During this study, only ca. 7% (7 of 102) of the bark beetles known from eastern North America were found on Arnold Air Force Base, while 25% (12 of 48) of the eastern North American ambrosia beetles were collected. Seven species of ambrosia beetles (Ambrosiodmus tachygraphus [Zimmermann], A. obliquus [LeConte], Xyleborus affinis Eichhoff, X. ferrugineus [F.], X. pubescens [Zimmermann]), and two exotic species (X. pelliculosus Eichhoff and Xylosandrus crassiusculus [Motschulsky]) and one species of bark beetle (Dryocoetes granicollis [LeConte]) represent new state records for Tennessee. Four of the 12 ambrosia beetles collected (Xyleborinus saxesini [Ratzerburg], Xyleborus atratus Eichhoff, X. pelliculosus, and Xylosandrus crassiusculus) are exotic species introduced from eastern Asia. The number of species collected at each site ranged from 11 at Sinking Pond to 1 from the three grassland-type habitats. Five of eight sampling methods yielded scolytid beetles; however, several species were captured only when we used specific sampling methods, illustrating the importance of incorporating diverse approaches to collecting scolytids to assess species composition. Diecinueve especies de escarabajos (Coleoptera: Scolytidae) fueron colectados en 8 de 11 sitios localizados en Arnold Air Force Base dentro de los 'barrens' del sureste de Highland Rim en el centro de Tennessee, USA. Estos 'barrens' se asemejan a las praderas dominadas por pastos del centro oeste de los Estados Unidos y son habitadas por muchas especies de plantas raras y de distribución desjunta. Aunque mucho se sabe de las especies de plantas de estos lugares de biodiversidad únicos, poca información está disponible sobre las especies de insectos. No existen reportes previos que hayandocumentado especies de la familia Scolytidae en este hábitat único. Durante este estudio, sólo aproximadamente el 7% (7 de 102) de los esca